0.3.12-alpha: version and release notes

Opening AntennaPod while Metrolist played switched Gearslip's player to
AntennaPod, so the nav bar lost the music and its buttons drove the wrong app.
Leaving an app where nothing started goes back to the one that kept playing.

.github/release-notes.md

@@ -1,15 +1,20 @@
-Gearslip 0.3.01 connects wirelessly on more phones and dongles.
+Gearslip 0.3.12 gives the car screen a fresh look and fixes the wireless loop 0.3.02 caused on some head units.
 
-## Fixed
-- Wireless works with dongles that send their Wi-Fi details before their address.
-- A VPN no longer stops a wireless drive without a word. Gearslip tries the phone's ordinary route around it, and if the VPN still blocks the car, Gearslip says so. To fix it for good, exclude Gearslip in your VPN app.
-- When Android won't ask for the Nearby devices permission, a button opens Gearslip's settings, where you can turn it on.
+## New
+- Navigation cards sit down the left side, with a bigger turn card that shows your lane. The map keeps the right side.
+- The car screen and the phone app take their colors from your phone's Material You palette.
+- The car's settings sit on the phone's home screen, each group on its own screen.
+- Put the home screen's player left or right of the map.
+- The browser shows the page title, and it has an address bar, forward, reload, and a start page.
+- If Gearslip lacks call permissions, the car's Phone screen asks for them on the phone.
 
 ## Changed
-- An app that someone else has re-signed, such as a modified Waze, no longer shows the red X when it accepts Gearslip.
-- Support Gearslip through Liberapay, Buy Me a Coffee, or Monero, in Settings.
-- Gearslip now belongs to Twink Software LLC, and its code lives at github.com/twinksoftware/gearslip. Old links still work.
-- The README lists Gearslip's signing certificate, so you can check your copy with AppVerifier.
+- Gearslip uses Car App Library 1.8. Map apps show the right turn arrows and route times, and Vela works fully.
+- Setup ends with recommended apps, then the button picker, then usage notes.
 
-## Known issues
-- Phone calls are unstable right now and may drop or fail to connect.
+## Fixed
+- Some head units, such as ZLink adapters, sent their Wi-Fi details twice. Gearslip rejoined the network each time and dropped the connection. It now ignores the repeat.
+- Gearslip no longer crashes when a wireless connection ends.
+- Opening a second music app without playing anything keeps the player on the song that's still playing.
+- Vela's speed sign is full size again.
+- RF Sentinel and other non-media car apps get their own tile in the launcher.

README.md

@@ -31,25 +31,27 @@ screen-sharing mode.
 |---|---|
 | ![The launcher, with every car app on the phone and the route in the bar below](docs/screenshots/launcher.png) | ![Vela Maps showing the route, with the music player beside the map](docs/screenshots/navigation.png) |
 | Your car apps in one place. A red X marks the ones that don't work yet. | Vela Maps navigating, with the player beside it. |
-| ![ViVi Music's song, art, and controls in Gearslip's player](docs/screenshots/music.png) | ![A new message card over Organic Maps](docs/screenshots/message.png) |
-| ViVi Music in Gearslip's player. | A new message, read aloud at a tap, over the map. |
-| ![The dashboard, with the weather, the next calendar event, and recent notifications](docs/screenshots/dashboard.png) | ![DuckDuckGo open in Gearslip's web browser](docs/screenshots/web.png) |
-| The weather, your next event, and what you missed. | Browse the web while parked. |
-| ![The voice assistant listening over Organic Maps](docs/screenshots/assistant.png) | ![Coffee shops near you in Vela Maps, with the music player beside the map](docs/screenshots/places.png) |
-| Ask for a place, a song, or an app. | Find coffee nearby without leaving the map. |
+| ![Metrolist's song, art, and controls in Gearslip's player](docs/screenshots/music.png) | ![A new message card over Vela Maps](docs/screenshots/message.png) |
+| Metrolist in Gearslip's player. | A new message, read aloud at a tap, over the map. |
+| ![The dashboard, with the weather, the week ahead, and recent notifications](docs/screenshots/dashboard.png) | ![DuckDuckGo open in Gearslip's web browser](docs/screenshots/web.png) |
+| The weather, your week, and what you missed. | Browse the web while parked. |
+| ![The voice assistant listening over Vela Maps](docs/screenshots/assistant.png) | ![Three routes to a coffee shop in Vela Maps, each with its time and distance](docs/screenshots/places.png) |
+| Ask for a place, a song, or an app. | Pick a route to coffee nearby. Each one shows its time and distance. |
 
 ## Features
 
 - **Phone calls.** Dial from a keypad, or search your contacts, then confirm before the
-  call goes out. When a call comes in, answer or decline it on the car screen.
+  call goes out. When a call comes in, answer or decline it on the car screen. During a
+  call, the nav bar shows who you're talking to, and you mute or hang up from there.
 - **Navigation.** Gearslip hosts real Car App Library map apps on the car screen.
-  Organic Maps, OsmAnd, and Flitsmeister work today. Vela runs, with rough
-  edges.
+  Organic Maps, Vela, OsmAnd, Flitsmeister, MAPS.ME, and MapQuest work today. While you
+  navigate, a big turn card on the left shows the arrow, the distance, and your lane, and
+  the map keeps the right side.
 - **Music.** Browse, play, and queue tracks from a car-enabled media app, with a Now
   Playing view, an Up Next queue, and lyrics. Type a search, and apps that accept one
   play the best match.
-- **The web.** A browser template with its own on-screen keyboard, for anything that
-  doesn't ship a car interface of its own.
+- **The web.** A browser with an address bar, back and forward, and its own on-screen
+  keyboard, for anything that doesn't ship a car interface of its own.
 - **Weather and the day ahead.** A dashboard screen shows the week's calendar next to
   the current and coming weather.
 - **Voice.** Tap the mic, or press the talk button on the wheel, and say "navigate to the
@@ -63,30 +65,35 @@ screen-sharing mode.
 - **Your apps, your order.** The launcher groups apps by kind: phone, maps, music,
   messaging, and the rest. Press and hold an app to move it.
 - **Car controls.** Steering wheel buttons, control knobs, and D-pads all work.
+- **Your phone's colors.** The car screen and the phone app take their colors from your
+  phone's Material You palette, and every card and button matches.
 - **Themes.** Choose flat buttons or skeuomorphic ones that look like real keys.
+- **Settings on the phone.** The car's settings sit on the phone's home screen too, so you
+  can set things up before you drive. A change on either screen shows on both.
 
 ## Status
 
 - **Wired or wireless.** Plug the phone into the car's USB port, or, in a car with wireless
   Android Auto, tap Connect wirelessly and pick the car. Pair the phone with the car over
-  Bluetooth first.
+  Bluetooth first. After the first wireless drive, Android asks once whether Gearslip may
+  watch for that car; from then on, Gearslip connects whenever the car's Bluetooth does.
 - **Setup walks you through it.** First launch asks for the Android Auto certificate,
   then one permission at a time, each with a plain reason and an Allow or Skip. A help
   screen inside the car answers anything setup didn't cover.
-- **Templated apps work.** Gearslip renders all 16 template types that the Car App
-  Library defines, and it draws its own keyboard for search, sign-in, and text fields.
-  It has been tested against several real navigation and media apps.
+- **Templated apps work.** Gearslip renders the Car App Library's templates on the car
+  screen, and it draws its own keyboard for search, sign-in, and text fields. It has been
+  tested against several real navigation and media apps.
 - **Gearslip works with [LIVI](https://github.com/f-io/LIVI),** the open-source head unit
   used in homemade car dashboards.
 - **Some apps refuse Gearslip.** Spotify, Waze, and Google Messages use a version of
   Google's car library that accepts only Android Auto itself. Spotify still plays through
-  Gearslip's own player.
+  Gearslip's own player. TIDAL lets only approved apps browse its library.
 - **Calls use the car's Bluetooth,** as they do in Android Auto. Pair the phone with the
   car to hear calls through its speakers.
 - **Music reaches the car over Bluetooth or USB.** Setup asks which. Bluetooth is the
   default: Android never asks for permission, and your map app's voice reaches the car
-  too. USB sounds a little clearer, with no delay, but Android shows a screen-share
-  consent dialog once per drive. Gearslip never reads the screen; capturing playback is
+  too. USB sounds a little clearer, with no delay, but each drive Android asks you to
+  share your screen, which lets Gearslip send the sound. Gearslip never reads the screen; capturing playback is
   the only way an ordinary app can pass another app's audio along.
 - **Gearslip needs no adb, root, or Shizuku.** Every feature relies on an ordinary
   Android permission or an on-device consent dialog. For USB audio, setup offers two

gearslip/build.gradle.kts

@@ -38,9 +38,9 @@ android {
         applicationId = "app.seb3thehacker.gearslip"
         minSdk = 31
         targetSdk = 37
-        versionCode = 10
+        versionCode = 12
         // -PgearslipVersionName=0.1.99-test makes a build that thinks it's older, to try the updater.
-        versionName = project.findProperty("gearslipVersionName")?.toString() ?: "0.3.01-alpha"
+        versionName = project.findProperty("gearslipVersionName")?.toString() ?: "0.3.12-alpha"
         manifestPlaceholders["appLabel"] = "Gearslip"
         // Where opted-in phones send their daily usage note: the stats-worker/ Worker's address,
         // set as gearslipStatsUrl in gradle.properties. Left empty, nothing is ever sent.
@@ -74,8 +74,9 @@ android {
             applicationIdSuffix = ".dev"
             signingConfigs.findByName("release")?.let { signingConfig = it }
             manifestPlaceholders["appLabel"] = "Gearslip Debug"
-            // -Pr8 shrinks a debug build like a release one, to test R8 in the debug install.
-            if (project.hasProperty("r8")) {
+            // Shrunk with R8 like a release, so a debug install behaves like what ships (a keep
+            // rule missing for release shows up here first). -PnoR8 skips it for a quicker build.
+            if (!project.hasProperty("noR8")) {
                 isMinifyEnabled = true
                 isShrinkResources = true
                 proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
@@ -105,9 +106,10 @@ android {
 
 }
 
-// Renames the produced APK and moves it to the root build/ folder (<root>/build/Gearslip-debug.apk)
-// after the fact rather than fighting AGP's variant-output API across versions - simpler and
-// doesn't break when that API moves again.
+// Copies the produced APK to the root build/ folder (<root>/build/Gearslip-debug.apk) after the
+// fact rather than fighting AGP's variant-output API across versions - simpler and doesn't break
+// when that API moves again. A copy, not a move: AGP packages incrementally into the APK it left
+// last time, and with that file gone a build came out holding nothing but classes.dex.
 tasks.register("renameApk") {
     doLast {
         val rootBuildDir = rootProject.layout.buildDirectory.get().asFile
@@ -117,7 +119,6 @@ tasks.register("renameApk") {
             .forEach { apk ->
                 val renamed = File(rootBuildDir, "Gearslip-${apk.parentFile.name}.apk")
                 apk.copyTo(renamed, overwrite = true)
-                apk.delete()
             }
     }
 }

gearslip/src/main/AndroidManifest.xml

@@ -25,6 +25,9 @@
         hands over its Wi-Fi details; Gearslip then joins that network to reach the car.
     -->
     <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
+    <!-- Wireless auto-connect: Android tells Gearslip when a car it manages connects. -->
+    <uses-permission android:name="android.permission.REQUEST_OBSERVE_COMPANION_DEVICE_PRESENCE" />
+    <uses-feature android:name="android.software.companion_device_setup" android:required="false" />
     <uses-permission android:name="android.permission.BLUETOOTH" android:maxSdkVersion="30" />
     <uses-permission
         android:name="android.permission.NEARBY_WIFI_DEVICES"
@@ -159,6 +162,12 @@
           activity so Settings can switch off just this (AppSettings.setGearslipEnabled) and leave
           the head unit to Android Auto, without disabling the screen the switch is on.
         -->
+        <activity
+            android:name=".PermissionActivity"
+            android:exported="false"
+            android:excludeFromRecents="true"
+            android:theme="@style/Theme.Gearslip.Invisible" />
+
         <activity-alias
             android:name=".GearslipUsbAccessory"
             android:targetActivity=".GearslipActivity"
@@ -244,5 +253,15 @@
                 <action android:name="android.telecom.CallScreeningService" />
             </intent-filter>
         </service>
+
+        <!-- Told when a car approved for wireless auto-connect comes up over Bluetooth. -->
+        <service
+            android:name=".wireless.CarPresenceService"
+            android:exported="true"
+            android:permission="android.permission.BIND_COMPANION_DEVICE_SERVICE">
+            <intent-filter>
+                <action android:name="android.companion.CompanionDeviceService" />
+            </intent-filter>
+        </service>
     </application>
 </manifest>

gearslip/src/main/java/app/seb3thehacker/gearslip/FrameStretcher.kt

@@ -0,0 +1,190 @@
+package app.seb3thehacker.gearslip
+
+import android.graphics.SurfaceTexture
+import android.opengl.EGL14
+import android.opengl.EGLConfig
+import android.opengl.EGLContext
+import android.opengl.EGLDisplay
+import android.opengl.EGLExt
+import android.opengl.EGLSurface
+import android.opengl.GLES11Ext
+import android.opengl.GLES20
+import android.os.Handler
+import android.os.HandlerThread
+import android.view.Surface
+import java.nio.ByteBuffer
+import java.nio.ByteOrder
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.TimeUnit
+
+/**
+ * Stretches a [width] x [height] picture over the whole of an [outWidth] x [outHeight] encoder
+ * frame.
+ *
+ * For a head unit that squashes the frame onto a screen of another shape: Gearslip draws for the
+ * screen's real shape into [input], this stretches it the other way, and the car's squash brings
+ * it back. It works on the composited picture, so a map app's own surface is stretched with
+ * everything else - scaling Gearslip's UI alone would leave the map squashed.
+ */
+class FrameStretcher(
+    private val output: Surface,
+    val width: Int,
+    val height: Int,
+    private val outWidth: Int,
+    private val outHeight: Int,
+) {
+
+    private val thread = HandlerThread("gearslip-stretch").apply { start() }
+    private val handler = Handler(thread.looper)
+
+    private var display: EGLDisplay = EGL14.EGL_NO_DISPLAY
+    private var context: EGLContext = EGL14.EGL_NO_CONTEXT
+    private var eglSurface: EGLSurface = EGL14.EGL_NO_SURFACE
+    private var program = 0
+    private var texture: SurfaceTexture? = null
+    private val transform = FloatArray(16)
+
+    /** Where to draw. Valid once [start] returns true. */
+    lateinit var input: Surface
+        private set
+
+    /** Sets up on its own thread and waits for it; false if the GPU wouldn't play along. */
+    fun start(): Boolean {
+        val done = CountDownLatch(1)
+        var ok = false
+        handler.post {
+            ok = runCatching { setUp() }
+                .onFailure { GearslipLog.e("stretch: could not set up", it) }
+                .isSuccess
+            done.countDown()
+        }
+        done.await(2, TimeUnit.SECONDS)
+        if (!ok) release()
+        return ok
+    }
+
+    fun release() {
+        handler.post {
+            runCatching { if (::input.isInitialized) input.release() }
+            runCatching { texture?.release() }
+            texture = null
+            if (display != EGL14.EGL_NO_DISPLAY) {
+                EGL14.eglMakeCurrent(display, EGL14.EGL_NO_SURFACE, EGL14.EGL_NO_SURFACE, EGL14.EGL_NO_CONTEXT)
+                if (eglSurface != EGL14.EGL_NO_SURFACE) EGL14.eglDestroySurface(display, eglSurface)
+                if (context != EGL14.EGL_NO_CONTEXT) EGL14.eglDestroyContext(display, context)
+                EGL14.eglTerminate(display)
+            }
+            display = EGL14.EGL_NO_DISPLAY
+            thread.quitSafely()
+        }
+    }
+
+    private fun setUp() {
+        display = EGL14.eglGetDisplay(EGL14.EGL_DEFAULT_DISPLAY)
+        val version = IntArray(2)
+        check(EGL14.eglInitialize(display, version, 0, version, 1)) { "eglInitialize failed" }
+        val configs = arrayOfNulls<EGLConfig>(1)
+        val count = IntArray(1)
+        val attributes = intArrayOf(
+            EGL14.EGL_RED_SIZE, 8, EGL14.EGL_GREEN_SIZE, 8, EGL14.EGL_BLUE_SIZE, 8,
+            EGL14.EGL_RENDERABLE_TYPE, EGL14.EGL_OPENGL_ES2_BIT,
+            EGL_RECORDABLE_ANDROID, 1,
+            EGL14.EGL_NONE,
+        )
+        check(EGL14.eglChooseConfig(display, attributes, 0, configs, 0, 1, count, 0) && count[0] > 0) {
+            "no EGL config"
+        }
+        context = EGL14.eglCreateContext(
+            display, configs[0], EGL14.EGL_NO_CONTEXT,
+            intArrayOf(EGL14.EGL_CONTEXT_CLIENT_VERSION, 2, EGL14.EGL_NONE), 0,
+        )
+        eglSurface = EGL14.eglCreateWindowSurface(display, configs[0], output, intArrayOf(EGL14.EGL_NONE), 0)
+        check(EGL14.eglMakeCurrent(display, eglSurface, eglSurface, context)) { "eglMakeCurrent failed" }
+
+        program = link(VERTEX, FRAGMENT)
+        val ids = IntArray(1)
+        GLES20.glGenTextures(1, ids, 0)
+        GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, ids[0])
+        GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_LINEAR)
+        GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR)
+        GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_CLAMP_TO_EDGE)
+        GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_CLAMP_TO_EDGE)
+
+        texture = SurfaceTexture(ids[0]).apply {
+            setDefaultBufferSize(width, height)
+            setOnFrameAvailableListener({ draw() }, handler)
+        }
+        input = Surface(texture)
+        GearslipLog.i("stretch: drawing ${width}x$height, stretched to fill ${outWidth}x$outHeight")
+    }
+
+    private fun draw() {
+        val tex = texture ?: return
+        runCatching {
+            tex.updateTexImage()
+            tex.getTransformMatrix(transform)
+            GLES20.glViewport(0, 0, outWidth, outHeight)
+            GLES20.glUseProgram(program)
+            val position = GLES20.glGetAttribLocation(program, "aPosition")
+            val coord = GLES20.glGetAttribLocation(program, "aCoord")
+            GLES20.glEnableVertexAttribArray(position)
+            GLES20.glVertexAttribPointer(position, 2, GLES20.GL_FLOAT, false, 0, QUAD)
+            GLES20.glEnableVertexAttribArray(coord)
+            GLES20.glVertexAttribPointer(coord, 2, GLES20.GL_FLOAT, false, 0, COORDS)
+            GLES20.glUniformMatrix4fv(GLES20.glGetUniformLocation(program, "uTransform"), 1, false, transform, 0)
+            GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4)
+            EGLExt.eglPresentationTimeANDROID(display, eglSurface, tex.timestamp)
+            EGL14.eglSwapBuffers(display, eglSurface)
+        }.onFailure { GearslipLog.e("stretch: draw failed", it) }
+    }
+
+    private fun link(vertex: String, fragment: String): Int {
+        fun compile(type: Int, source: String): Int = GLES20.glCreateShader(type).also {
+            GLES20.glShaderSource(it, source)
+            GLES20.glCompileShader(it)
+            val status = IntArray(1)
+            GLES20.glGetShaderiv(it, GLES20.GL_COMPILE_STATUS, status, 0)
+            check(status[0] != 0) { "shader: ${GLES20.glGetShaderInfoLog(it)}" }
+        }
+        return GLES20.glCreateProgram().also {
+            GLES20.glAttachShader(it, compile(GLES20.GL_VERTEX_SHADER, vertex))
+            GLES20.glAttachShader(it, compile(GLES20.GL_FRAGMENT_SHADER, fragment))
+            GLES20.glLinkProgram(it)
+            val status = IntArray(1)
+            GLES20.glGetProgramiv(it, GLES20.GL_LINK_STATUS, status, 0)
+            check(status[0] != 0) { "program: ${GLES20.glGetProgramInfoLog(it)}" }
+        }
+    }
+
+    private companion object {
+        /** EGL_RECORDABLE_ANDROID: the config must be able to feed a video encoder. */
+        const val EGL_RECORDABLE_ANDROID = 0x3142
+
+        val QUAD = floats(-1f, -1f, 1f, -1f, -1f, 1f, 1f, 1f)
+        val COORDS = floats(0f, 0f, 1f, 0f, 0f, 1f, 1f, 1f)
+
+        fun floats(vararg values: Float) = ByteBuffer.allocateDirect(values.size * 4)
+            .order(ByteOrder.nativeOrder()).asFloatBuffer().apply { put(values); position(0) }
+
+        const val VERTEX = """
+            attribute vec4 aPosition;
+            attribute vec4 aCoord;
+            uniform mat4 uTransform;
+            varying vec2 vCoord;
+            void main() {
+                gl_Position = aPosition;
+                vCoord = (uTransform * aCoord).xy;
+            }
+        """
+
+        const val FRAGMENT = """
+            #extension GL_OES_EGL_image_external : require
+            precision mediump float;
+            varying vec2 vCoord;
+            uniform samplerExternalOES sTexture;
+            void main() {
+                gl_FragColor = texture2D(sTexture, vCoord);
+            }
+        """
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/Framing.kt

@@ -1,20 +1,10 @@
 package app.seb3thehacker.gearslip
 
 import java.io.ByteArrayOutputStream
+import java.io.IOException
+import java.io.OutputStream
 
-/**
- * Android Auto frame layout, transcribed from aasdk.
- *
- * FrameHeader::getData (src/Messenger/FrameHeader.cpp:47-55),
- * FrameSize::getData (src/Messenger/FrameSize.cpp:49-62) and
- * MessageOutStream::compoundFrame (src/Messenger/MessageOutStream.cpp:100-120):
- *
- *   byte 0     channel id
- *   byte 1     frameType | encryption | messageType
- *   bytes 2-3  uint16 BE  payload length of THIS frame
- *   bytes 4-7  uint32 BE  total message length - present ONLY when frameType == FIRST
- *   payload    uint16 BE message id, then the body
- */
+/** Android Auto framing with plaintext fragmentation before per-frame encryption. */
 object Frames {
 
     const val CHANNEL_CONTROL = 0
@@ -36,8 +26,11 @@ object Frames {
     const val MESSAGE_SPECIFIC = 0
     const val MESSAGE_CONTROL = 1 shl 2
 
-    /** aasdk splits at this size (MessageOutStream.hpp:62). Nothing the spike sends is close. */
-    const val MAX_FRAME_PAYLOAD = 0x4000
+    // Android Auto's default fragment budget includes the framing header. TLS adds overhead.
+    private const val FRAGMENT_SIZE = 0x3f00
+    private const val HEADER_SIZE = 4
+    private const val FIRST_HEADER_SIZE = 8
+    const val MAX_FRAME_PAYLOAD = FRAGMENT_SIZE - HEADER_SIZE
 
     class Frame(
         val channel: Int,
@@ -45,6 +38,7 @@ object Frames {
         val encrypted: Boolean,
         val messageType: Int,
         val payload: ByteArray,
+        val totalSize: Int? = null,
     )
 
     /**
@@ -60,6 +54,11 @@ object Frames {
         frameType: Int = TYPE_BULK,
         totalSize: Int? = null,
     ): ByteArray {
+        require(channel in 0..255 && payload.size <= 0xffff)
+        require(frameType in TYPE_MIDDLE..TYPE_BULK)
+        require(messageType == MESSAGE_SPECIFIC || messageType == MESSAGE_CONTROL)
+        require((frameType == TYPE_FIRST) == (totalSize != null))
+        require(totalSize == null || totalSize in 2..MAX_MESSAGE_SIZE)
         val flags = frameType or messageType or (if (encrypted) ENCRYPTED else 0)
         val header = byteArrayOf(
             channel.toByte(),
@@ -67,7 +66,7 @@ object Frames {
             ((payload.size shr 8) and 0xFF).toByte(),
             (payload.size and 0xFF).toByte(),
         )
-        if (frameType != TYPE_FIRST || totalSize == null) return header + payload
+        if (totalSize == null) return header + payload
         val extended = byteArrayOf(
             ((totalSize shr 24) and 0xFF).toByte(),
             ((totalSize shr 16) and 0xFF).toByte(),
@@ -77,6 +76,43 @@ object Frames {
         return header + extended + payload
     }
 
+    /** Splits plaintext before encryption; FIRST carries the complete plaintext length. */
+    fun writeMessage(
+        output: OutputStream,
+        channel: Int,
+        encrypted: Boolean,
+        messageType: Int,
+        message: ByteArray,
+        encrypt: (ByteArray) -> ByteArray,
+    ): Int {
+        require(message.size in 2..MAX_MESSAGE_SIZE)
+        val fragmented = message.size > FRAGMENT_SIZE - HEADER_SIZE
+        require(messageType != MESSAGE_CONTROL || !fragmented) { "Channel control messages cannot be fragmented" }
+        var offset = 0
+        var frames = 0
+        while (offset < message.size) {
+            val first = fragmented && offset == 0
+            val headerSize = if (first) FIRST_HEADER_SIZE else HEADER_SIZE
+            val end = minOf(offset + FRAGMENT_SIZE - headerSize, message.size)
+            val type = when {
+                !fragmented -> TYPE_BULK
+                first -> TYPE_FIRST
+                end == message.size -> TYPE_LAST
+                else -> TYPE_MIDDLE
+            }
+            val chunk = message.copyOfRange(offset, end)
+            output.write(build(channel, encrypted, if (encrypted) encrypt(chunk) else chunk,
+                messageType, type, if (type == TYPE_FIRST) message.size else null))
+            offset = end
+            frames++
+        }
+        return frames
+    }
+
+    // Local resource limits, not protocol constants. No supported media packet needs more.
+    private const val MAX_MESSAGE_SIZE = 16 * 1024 * 1024
+    private const val MAX_BUFFERED_SIZE = 32 * 1024 * 1024
+
     /**
      * Pulls whole frames out of an accumulating buffer.
      *
@@ -87,6 +123,8 @@ object Frames {
         private var pending = ByteArray(0)
 
         fun append(data: ByteArray, length: Int) {
+            require(length in 0..data.size)
+            if (length > MAX_BUFFERED_SIZE - pending.size) throw IOException("Frame buffer limit exceeded")
             val grown = ByteArray(pending.size + length)
             System.arraycopy(pending, 0, grown, 0, pending.size)
             System.arraycopy(data, 0, grown, pending.size, length)
@@ -106,30 +144,53 @@ object Frames {
             val total = headerLength + frameSize
             if (pending.size < total) return null
 
+            val messageSize = if (frameType == TYPE_FIRST) {
+                var size = 0L
+                for (i in 4..7) size = (size shl 8) or (pending[i].toLong() and 0xff)
+                if (size !in 2..MAX_MESSAGE_SIZE.toLong()) throw IOException("Invalid fragmented message length: $size")
+                size.toInt()
+            } else null
             val payload = pending.copyOfRange(headerLength, total)
             pending = pending.copyOfRange(total, pending.size)
             return Frame(
-                channel, frameType, (flags and ENCRYPTED) != 0, flags and MESSAGE_CONTROL, payload,
+                channel, frameType, (flags and ENCRYPTED) != 0, flags and MESSAGE_CONTROL, payload, messageSize,
             )
         }
     }
 
-    /** Rejoins FIRST/MIDDLE/LAST runs. Payloads arrive already decrypted. */
+    /** Rejoins messages on independent channels, validating their plaintext length and flags. */
     class Assembler {
-        private val partial = HashMap<Int, ByteArrayOutputStream>()
+        private class Partial(val first: Frame, val data: ByteArrayOutputStream = ByteArrayOutputStream())
+        private val partial = HashMap<Int, Partial>()
+        private var buffered = 0
 
-        fun offer(frame: Frame, payload: ByteArray): ByteArray? = when (frame.frameType) {
-            TYPE_BULK -> payload
-            TYPE_FIRST -> {
-                partial[frame.channel] = ByteArrayOutputStream().apply { write(payload) }
-                null
+        fun offer(frame: Frame, payload: ByteArray): ByteArray? {
+            if (frame.frameType == TYPE_BULK) {
+                if (partial.containsKey(frame.channel)) fail("Complete message interrupted fragments")
+                return payload
             }
-            TYPE_MIDDLE -> {
-                partial[frame.channel]?.write(payload)
-                null
-            }
-            TYPE_LAST -> partial.remove(frame.channel)?.apply { write(payload) }?.toByteArray()
-            else -> null
+            val message = if (frame.frameType == TYPE_FIRST) {
+                if (frame.totalSize == null || partial.containsKey(frame.channel)) fail("Invalid first fragment")
+                Partial(frame).also { partial[frame.channel] = it }
+            } else partial[frame.channel] ?: fail("Fragment without a first frame")
+            val first = message.first
+            if (first.encrypted != frame.encrypted || first.messageType != frame.messageType) fail("Fragment flags changed")
+            val expected = first.totalSize ?: fail("Missing total size")
+            if (expected !in 2..MAX_MESSAGE_SIZE || payload.size > expected - message.data.size()) fail("Fragment exceeds message length")
+            if (payload.size > MAX_BUFFERED_SIZE - buffered) fail("Fragment buffer limit exceeded")
+            message.data.write(payload)
+            buffered += payload.size
+            if (frame.frameType != TYPE_LAST) return null
+            if (message.data.size() != expected) fail("Truncated fragmented message")
+            partial.remove(frame.channel)
+            buffered -= message.data.size()
+            return message.data.toByteArray()
+        }
+
+        private fun fail(message: String): Nothing {
+            partial.clear()
+            buffered = 0
+            throw IOException(message)
         }
     }
 }

gearslip/src/main/java/app/seb3thehacker/gearslip/GearslipActivity.kt

@@ -14,7 +14,6 @@ import android.os.ParcelFileDescriptor
 import android.provider.Settings
 import android.view.MotionEvent
 import android.view.Surface
-import android.view.WindowManager
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.compose.runtime.collectAsState
@@ -117,6 +116,17 @@ class GearslipActivity : ComponentActivity(), Projection {
         }
     }
 
+    /** Android's one-time "Allow" for a car to connect by itself; see [WirelessAuto]. */
+    private var approvingCar: String? = null
+    private val carApproval = registerForActivityResult(
+        androidx.activity.result.contract.ActivityResultContracts.StartIntentSenderForResult(),
+    ) { result ->
+        val address = approvingCar ?: return@registerForActivityResult
+        approvingCar = null
+        if (result.resultCode == RESULT_OK) app.seb3thehacker.gearslip.wireless.WirelessAuto.approved(this, address)
+        else app.seb3thehacker.gearslip.wireless.WirelessAuto.declined(this, address)
+    }
+
     /** Setting Gearslip as the phone's caller ID and spam app - what lets it decline a ringing call. */
     private val callScreeningRole = registerForActivityResult(StartActivityForResult()) { result ->
         if (result.resultCode != RESULT_OK) GearslipLog.w("calls: call screening role declined")
@@ -130,7 +140,6 @@ class GearslipActivity : ComponentActivity(), Projection {
         // is both a bad first impression and unreliable: Android does not consistently show more
         // than one system permission dialog fired back-to-back, which was silently dropping some.
         enableEdgeToEdge()
-        window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
 
         GearslipLog.init(this)
         GearslipLog.installCrashHandler()
@@ -138,6 +147,12 @@ class GearslipActivity : ComponentActivity(), Projection {
         app.seb3thehacker.gearslip.wireless.WirelessLink.onConnected = { socket ->
             runOnUiThread { startWireless(socket) }
         }
+        app.seb3thehacker.gearslip.wireless.WirelessAuto.showApproval = { chooser, address ->
+            runOnUiThread {
+                approvingCar = address
+                carApproval.launch(androidx.activity.result.IntentSenderRequest.Builder(chooser).build())
+            }
+        }
         CarSettings.init(this)
         AppSettings.applyGearslipEnabled(this)
         // A capture that died without tidying up would leave notifications exposed to every
@@ -216,6 +231,7 @@ class GearslipActivity : ComponentActivity(), Projection {
     override fun onDestroy() {
         super.onDestroy()
         app.seb3thehacker.gearslip.wireless.WirelessLink.onConnected = null
+        app.seb3thehacker.gearslip.wireless.WirelessAuto.showApproval = null
         runCatching { unregisterReceiver(detachReceiver) }
         PhoneMirror.onStartRequested = null
         PhoneMirror.onTokenReady = null
@@ -304,6 +320,10 @@ class GearslipActivity : ComponentActivity(), Projection {
     }
 
     private fun handleIntent(intent: Intent?) {
+        if (intent?.action == app.seb3thehacker.gearslip.wireless.WirelessAuto.ACTION_CAR_NEARBY) {
+            connectToNearbyCar(intent.getStringExtra(app.seb3thehacker.gearslip.wireless.WirelessAuto.EXTRA_ADDRESS))
+            return
+        }
         if (intent?.action != UsbManager.ACTION_USB_ACCESSORY_ATTACHED) return
         // Switched off in Settings: the system shouldn't route the car here at all, but if it
         // does, leave the accessory alone.
@@ -321,6 +341,39 @@ class GearslipActivity : ComponentActivity(), Projection {
         start(accessory)
     }
 
+    /** A known car came up over Bluetooth: connect wirelessly, unless USB or another try is already on it. */
+    private fun connectToNearbyCar(address: String?) {
+        if (address == null) return
+        if (!AppSettings.gearslipEnabled(this)) {
+            GearslipLog.i("auto-connect: Gearslip is switched off - not connecting")
+            return
+        }
+        if (descriptor != null) {
+            GearslipLog.i("auto-connect: the car is on USB already - staying on USB")
+            return
+        }
+        // Only a session that's still running counts. One the car ended (a ByeBye, a dropped
+        // network) leaves its runner behind, since only Gearslip ending a session clears it, and
+        // that used to make every later auto-connect quietly do nothing.
+        if (worker?.isAlive == true || app.seb3thehacker.gearslip.wireless.WirelessLink.busy) {
+            GearslipLog.i("auto-connect: a session is already running")
+            return
+        }
+        if (runner != null) closeAccessory(stopWireless = false)
+        if (checkSelfPermission(android.Manifest.permission.BLUETOOTH_CONNECT) != android.content.pm.PackageManager.PERMISSION_GRANTED) {
+            GearslipLog.w("auto-connect: needs the Nearby devices permission")
+            return
+        }
+        val adapter = getSystemService(android.bluetooth.BluetoothManager::class.java)?.adapter
+        val device = adapter?.let { runCatching { it.getRemoteDevice(address) }.getOrNull() }
+        if (device == null) {
+            GearslipLog.w("auto-connect: Bluetooth couldn't hand over the car")
+            return
+        }
+        GearslipLog.i("auto-connect: connecting")
+        app.seb3thehacker.gearslip.wireless.WirelessLink.start(this, device)
+    }
+
     private fun start(accessory: UsbAccessory) {
         // A fresh ATTACHED intent means the system wants a new session, whatever state the old
         // one is in - closing first guarantees openAccessory() below never fights a descriptor

gearslip/src/main/java/app/seb3thehacker/gearslip/GearslipLog.kt

@@ -52,6 +52,46 @@ object GearslipLog {
         file = File(dir, "gearslip-$name.log")
         i("log file: ${file?.absolutePath}")
         SessionReport.init(context)
+        // One file per launch adds up; the newest are the ones anyone asks for.
+        io.execute { logFiles(dir).drop(KEEP_FILES).forEach { it.delete() } }
+    }
+
+    private const val KEEP_FILES = 30
+
+    private fun logFiles(dir: File): List<File> =
+        dir.listFiles { f -> f.isFile && f.name.startsWith("gearslip-") && f.name.endsWith(".log") }
+            ?.sortedByDescending { it.name }.orEmpty()
+
+    /** A log from an earlier launch: when it started, and what a glance at it tells. */
+    class PastLog(val file: File, val started: Date?, val crashed: Boolean, val car: String?)
+
+    /**
+     * Earlier launches' logs, newest first. Each launch starts a fresh file, so after a crash the
+     * one that saw it is here rather than on the live screen.
+     */
+    fun pastLogs(context: Context): List<PastLog> {
+        val dir = context.getExternalFilesDir(null) ?: return emptyList()
+        val parse = SimpleDateFormat("yyyyMMdd-HHmmss", Locale.US)
+        return logFiles(dir).filter { it != file }.map { f ->
+            val text = runCatching { f.readText() }.getOrDefault("")
+            PastLog(
+                file = f,
+                started = runCatching { parse.parse(f.name.removePrefix("gearslip-").removeSuffix(".log")) }.getOrNull(),
+                crashed = "FATAL uncaught" in text,
+                car = Regex("""car="([^"]+)"""").findAll(text).lastOrNull()?.groupValues?.get(1),
+            )
+        }
+    }
+
+    /** An earlier launch's log, copied to the cache dir for sharing like [shareableFile]. */
+    fun shareableFile(context: Context, past: File): android.net.Uri {
+        val dir = File(context.cacheDir, "shared").apply { mkdirs() }
+        dir.listFiles()?.forEach { it.delete() }
+        val out = File(dir, "gearslip-log-${past.name.removePrefix("gearslip-").removeSuffix(".log")}.txt")
+        past.copyTo(out, overwrite = true)
+        return androidx.core.content.FileProvider.getUriForFile(
+            context, "${context.packageName}.logshare", out,
+        )
     }
 
     fun snapshot(): List<String> = synchronized(live) { live.toList() }

gearslip/src/main/java/app/seb3thehacker/gearslip/GearslipRunner.kt

@@ -2,6 +2,7 @@ package app.seb3thehacker.gearslip
 
 import android.os.Build
 import app.seb3thehacker.gearslip.audio.AudioLink
+import app.seb3thehacker.gearslip.audio.CarAudio
 import app.seb3thehacker.gearslip.audio.CarMic
 import app.seb3thehacker.gearslip.media.CarMediaStatus
 import app.seb3thehacker.gearslip.car.BluetoothAudioCheck
@@ -12,12 +13,18 @@ import app.seb3thehacker.gearslip.car.DirectionsVoice
 import app.seb3thehacker.gearslip.car.CarAssistant
 import app.seb3thehacker.gearslip.car.CarEnvironment
 import app.seb3thehacker.gearslip.car.CarKeys
+import app.seb3thehacker.gearslip.car.ScreenFit
 import app.seb3thehacker.gearslip.car.CarSensors
 import app.seb3thehacker.gearslip.car.CarServices
 import app.seb3thehacker.gearslip.car.CarSettings
+import java.io.IOException
+import app.seb3thehacker.gearslip.protocol.InputProtocol
 import java.io.InputStream
 import java.io.OutputStream
+import java.util.concurrent.Executors
 import java.util.concurrent.FutureTask
+import java.util.concurrent.RejectedExecutionException
+import java.util.concurrent.TimeUnit
 
 /**
  * Drives the phone side of the control-channel handshake far enough to answer one question:
@@ -59,6 +66,7 @@ class GearslipRunner(
     /** Waits for the certificate only when TLS is first needed; see [run]. */
     private val tls: PhoneTls by lazy { identityTask.get() }
     private var authenticationFailed = false
+    private var drainWriterOnExit = false
     @Volatile private var stopped = false
 
     @Volatile private var state = State.WAIT_VERSION
@@ -71,6 +79,12 @@ class GearslipRunner(
     private var vehicleProfile: VehicleProfile? = null
     @Volatile private var videoStarted = false
     private var videoSource: VideoSource? = null
+
+    /** Between the car UI and the encoder when the car squashes the frame (see [screenShape]). */
+    private var stretcher: FrameStretcher? = null
+
+    /** What the car UI draws at when [stretcher] is on; touches are scaled into it. */
+    @Volatile private var drawSize: Pair<Int, Int>? = null
     @Volatile private var inFlight = 0
     /** Guards [inFlight]: the encoder thread waits on it for the head unit's acks. */
     private val ackLock = Object()
@@ -146,6 +160,8 @@ class GearslipRunner(
             reportDisconnect()
         } finally {
             running = false
+            writer.shutdown()
+            if (drainWriterOnExit) writer.awaitTermination(2, TimeUnit.SECONDS)
             writer.shutdownNow()
             log.flush()
         }
@@ -160,6 +176,9 @@ class GearslipRunner(
         synchronized(ackLock) { ackLock.notifyAll() } // free an encoder waiting on an ack
         videoSource?.stop()
         videoSource = null
+        stretcher?.release()
+        stretcher = null
+        CarAudio.openSink = null
         audioLink?.close()
         audioLink = null
         guidanceLink?.close()
@@ -181,7 +200,7 @@ class GearslipRunner(
 
     private fun handleFrame(frame: Frames.Frame) {
         // A rejected handshake cannot consume later messages as if authentication succeeded.
-        if (authenticationFailed || stopped) return
+        if (authenticationFailed || stopped || !running) return
         val payload = if (frame.encrypted) {
             if (!tls.handshakeComplete) {
                 log.w("encrypted frame arrived before the handshake finished - ignoring")
@@ -192,7 +211,10 @@ class GearslipRunner(
             frame.payload
         }
 
-        val message = assembler.offer(frame, payload) ?: return
+        val message = if (frame.messageType == Frames.MESSAGE_CONTROL) {
+            if (frame.frameType != Frames.TYPE_BULK) throw IOException("Fragmented channel control message")
+            payload
+        } else assembler.offer(frame, payload) ?: return
         if (message.size < 2) {
             log.w("runt message on channel ${frame.channel}")
             return
@@ -204,6 +226,7 @@ class GearslipRunner(
         lastProgress = System.currentTimeMillis()
 
         if (frame.channel != Frames.CHANNEL_CONTROL) {
+            if (state != State.DONE || !frame.encrypted) return
             if (frame.channel == videoChannelId) {
                 onVideoMessage(messageId, body)
             } else if (frame.channel == inputChannelId) {
@@ -239,6 +262,9 @@ class GearslipRunner(
             }
             return
         }
+        if (messageId !in setOf(MSG_VERSION_REQUEST, MSG_ENCAPSULATED_SSL, MSG_AUTH_COMPLETE,
+                MSG_BYEBYE_REQUEST, MSG_UNEXPECTED_MESSAGE, MSG_FRAMING_ERROR) &&
+            (!frame.encrypted || state != State.DONE && state != State.WAIT_SDR)) return
 
         when (messageId) {
             MSG_VERSION_REQUEST -> onVersionRequest(body)
@@ -247,11 +273,25 @@ class GearslipRunner(
             MSG_SERVICE_DISCOVERY_RESPONSE -> onServiceDiscoveryResponse(body)
             MSG_PING_REQUEST -> onPingRequest(body)
             MSG_BYEBYE_REQUEST -> onByeByeRequest(body)
-            AudioLink.MSG_FOCUS_RESPONSE -> audioLink?.onFocus(Protobuf.readInt32Field(body, 1) ?: 0)
+            MSG_UNEXPECTED_MESSAGE, MSG_FRAMING_ERROR -> onProtocolError(messageId)
+            AudioLink.MSG_FOCUS_RESPONSE -> {
+                // One answer for both sinks: it is the directions' while they wait on one.
+                val state = Protobuf.readInt32Field(body, 1) ?: 0
+                val guidance = guidanceLink
+                if (guidance != null && guidance.expectsFocusAnswer()) guidance.onFocus(state) else audioLink?.onFocus(state)
+            }
             else -> log.i("unhandled control message id=$messageId (${body.size} bytes) - continuing")
         }
     }
 
+    private fun onProtocolError(messageId: Int) {
+        val detail = if (messageId == MSG_FRAMING_ERROR) "framing error" else "unexpected message"
+        log.w("head unit terminated the protocol: $detail")
+        SessionReport.fail(SessionReport.Category.UNKNOWN, detail, state.name, "protocol $messageId")
+        SessionStatus.failed("Protocol error", "The head unit reported a $detail.")
+        running = false
+    }
+
     /**
      * The head unit asking to end the session. It drops USB a few seconds later whether or not
      * we answer, so the point here is the reason: an Audi MIB2+ sent this about a second after
@@ -265,16 +305,23 @@ class GearslipRunner(
             3 -> "NOT_SUPPORTED"
             4 -> "NOT_CURRENTLY_SUPPORTED"
             5 -> "PROBE_SUPPORTED"
+            6 -> "WIRELESS_PROJECTION_DISABLED"
+            7 -> "POWER_DOWN"
+            8 -> "USER_PROFILE_SWITCH"
             else -> "unknown"
         }
         log.w("<- ByeByeRequest: reason=$reason ($name) in state $state")
         log.hex("   byebye raw", body)
         SessionReport.fail(SessionReport.Category.BYEBYE, "ByeByeRequest reason=$reason ($name)", state.name, "bye $reason")
-        send(MSG_BYEBYE_RESPONSE, ByteArray(0), encrypted = true)
+        send(MSG_BYEBYE_RESPONSE, ByteArray(0), encrypted = state == State.WAIT_SDR || state == State.DONE)
         log.i("-> ByeByeResponse")
+        drainWriterOnExit = true
+        running = false
+        SessionStatus.disconnected()
     }
 
     private fun onVersionRequest(body: ByteArray) {
+        if (state != State.WAIT_VERSION) return
         if (body.size < 4) {
             log.w("VersionRequest too short (${body.size} bytes)")
             return
@@ -284,24 +331,16 @@ class GearslipRunner(
         log.i("<- VersionRequest: head unit speaks $major.$minor")
         SessionReport.protocolVersion(major, minor)
 
-        // Always 1.3, on purpose. Every car that accepts Gearslip was tested this way, 1.5 units
-        // included. Echoing the car's own version was tried too: a 4.3 unit rejected the
-        // certificate either way, so the version doesn't decide acceptance. The log says so, since
-        // a car offering 1.5 and getting 1.3 back looks like a bug to anyone reading it.
-        val claim = CLAIM_VERSION ?: (major to minor)
-        val response = byteArrayOf(
-            ((claim.first shr 8) and 0xFF).toByte(), (claim.first and 0xFF).toByte(),
-            ((claim.second shr 8) and 0xFF).toByte(), (claim.second and 0xFF).toByte(),
-            0, 0, // STATUS_SUCCESS
-        )
-        send(MSG_VERSION_RESPONSE, response, encrypted = false)
-        log.i(
-            "-> VersionResponse: ${claim.first}.${claim.second} status=0 (STATUS_SUCCESS)" +
-                if (CLAIM_VERSION != null && claim != (major to minor)) {
-                    " - intended: Gearslip always answers ${claim.first}.${claim.second}, which cars " +
-                        "offering $major.$minor accept too"
-                } else "",
-        )
+        val response = ProtocolVersion.respond(major, minor)
+        send(MSG_VERSION_RESPONSE, response.bytes, encrypted = false)
+        log.i("-> VersionResponse: ${response.major}.${response.minor}, supported=${response.supported}")
+        if (!response.supported) {
+            authenticationFailed = true
+            drainWriterOnExit = true
+            running = false
+            SessionStatus.failed("Unsupported protocol", "The head unit requested protocol $major.$minor.")
+            return
+        }
         state = State.TLS_HANDSHAKE
         SessionStatus.connecting("Securing the link")
         log.i("awaiting ClientHello - the head unit is the TLS client, we are the server")
@@ -318,17 +357,13 @@ class GearslipRunner(
             if (stopped) return
             log.e("TLS handshake threw", t)
             SessionReport.fail(SessionReport.Category.TLS, "handshake threw", t, state.name)
-            log.verdict(
-                "NOT VIABLE (TLS rejected)",
-                "The head unit aborted the TLS handshake. A bad_certificate / unknown_ca / " +
-                    "handshake_failure alert here means it validates the phone's certificate.",
-            )
             SessionStatus.failed(
-                "Head unit rejected the certificate",
-                "The head unit aborted the secure handshake. It validates the phone's certificate.",
+                "Secure connection failed",
+                "The secure handshake could not be completed. Check the session log for details.",
             )
             state = State.DONE
             authenticationFailed = true
+            running = false
             SessionReport.print()
             return
         }
@@ -345,7 +380,7 @@ class GearslipRunner(
 
     private fun onAuthComplete(body: ByteArray) {
         val status = Protobuf.readInt32Field(body, 1)
-        if (state != State.WAIT_AUTH && !(state == State.TLS_HANDSHAKE && status in listOf(-2, -3))) return
+        if (state != State.WAIT_AUTH && !(state == State.TLS_HANDSHAKE && status != null && status != 0)) return
         log.i("<- AuthComplete: status=$status")
         status?.let { SessionReport.auth(it) }
 
@@ -356,17 +391,17 @@ class GearslipRunner(
                 SessionStatus.connecting("Certificate accepted - discovering services")
                 sendServiceDiscoveryRequest()
             }
-            -2 -> {
-                SessionReport.fail(SessionReport.Category.CERTIFICATE, "AuthComplete status -2 (certificate error)", state.name, "auth -2")
-                log.verdict(
-                    "NOT VIABLE (STATUS_CERTIFICATE_ERROR)",
-                    "The head unit explicitly rejected the phone's self-signed certificate. " +
-                        "This is a definitive no - it validates the phone against a trust chain " +
-                        "we cannot issue from.",
-                )
+            -2, -23, -24 -> {
+                val reason = when (status) {
+                    -23 -> "The phone's certificate is not valid yet."
+                    -24 -> "The phone's certificate has expired."
+                    else -> "The head unit refused the phone's certificate."
+                }
+                SessionReport.fail(SessionReport.Category.CERTIFICATE, "AuthComplete status $status", state.name, "auth $status")
+                log.w("certificate rejected: $reason")
                 SessionStatus.failed(
                     "Head unit rejected the certificate",
-                    "The head unit refused the phone's certificate (certificate error).",
+                    reason,
                 )
                 state = State.DONE
                 authenticationFailed = true
@@ -397,6 +432,7 @@ class GearslipRunner(
                 authenticationFailed = true
             }
         }
+        if (authenticationFailed) running = false
     }
 
     private fun sendServiceDiscoveryRequest() {
@@ -407,6 +443,7 @@ class GearslipRunner(
     }
 
     private fun onServiceDiscoveryResponse(body: ByteArray) {
+        if (state != State.WAIT_SDR) return
         log.i("<- ServiceDiscoveryResponse (${body.size} bytes, decrypted successfully)")
         // Field 5 is the car's serial number, and the Bluetooth service carries the car's
         // Bluetooth address. Either one identifies the car, and logs get shared, so both stay out.
@@ -527,7 +564,17 @@ class GearslipRunner(
             // as Android Auto does, instead of letting it play on to no one.
             onTakenBack = { CarServices.pausePhoneMedia("the car switched to another source") },
         )
-        openChannel(media.serviceId)
+        if (CarSettings.pipeAudio.value) {
+            openChannel(media.serviceId)
+        } else {
+            // Many cars switch their source to Android Auto the moment this channel opens, which
+            // cut off music the driver chose to play over Bluetooth. Open it only if they switch.
+            log.i("music goes over Bluetooth: the media channel stays closed, so the car keeps its own source")
+            CarAudio.openSink = {
+                CarAudio.openSink = null
+                openChannel(media.serviceId)
+            }
+        }
     }
 
     /** The car's directions channel, where [DirectionsVoice] reads out each turn. */
@@ -545,7 +592,7 @@ class GearslipRunner(
             tag = "guidance",
             sessionId = GUIDANCE_SESSION_ID,
             asksFocus = false,
-            onReady = { DirectionsVoice.attach(it) },
+            onReady = { DirectionsVoice.attach(it) { audioLink?.streaming == true } },
             onClose = { DirectionsVoice.detach(it) },
         )
         openChannel(guidance.serviceId)
@@ -619,12 +666,15 @@ class GearslipRunner(
 
     /** Turn-by-turn for the instrument cluster: the next turn, its road, and how far. */
     private fun startClusterNavChannel(serviceDiscoveryResponse: ByteArray) {
-        val channel = ServiceDiscovery.findNavStatusChannel(serviceDiscoveryResponse) ?: run {
+        val navigation = ServiceDiscovery.findNavStatusService(serviceDiscoveryResponse) ?: run {
             log.i("no navigation status channel - the cluster won't show turns")
             return
         }
+        val channel = navigation.serviceId
         log.i("navigation status channel: $channel")
-        clusterNav = ClusterNav(channel) { id, body -> send(id, body, encrypted = true, channel = channel) }
+        clusterNav = ClusterNav(channel, navigation.minimumIntervalMs.toLong()) { id, body ->
+            send(id, body, encrypted = true, channel = channel)
+        }
         openChannel(channel)
     }
 
@@ -680,7 +730,7 @@ class GearslipRunner(
      */
     private fun onNightSensor(body: ByteArray) {
         val night = Wire.bytes(Wire.fields(body), SENSOR_NIGHT) ?: return
-        val isNight = Wire.varint(Wire.fields(night), 1) == 1L
+        val isNight = (Wire.varint(Wire.fields(night), 1) ?: 0L) != 0L
         if (isNight != lastSensorNight) {
             lastSensorNight = isNight
             log.i("car says it's ${if (isNight) "night" else "day"}")
@@ -763,59 +813,60 @@ class GearslipRunner(
             MSG_KEY_BINDING_RESPONSE ->
                 log.i("<- KeyBindingResponse: status=${Protobuf.readInt32Field(body, 1)}")
 
-            MSG_INPUT_REPORT -> {
-                val report = Wire.fields(body)
-                // The 2018 Uconnect agrees to Exit but keeps showing our last frame and sending
-                // touches, which looked like a crash. A touch means our screen is still up there.
-                if (videoStarted && !videoProjected && Wire.bytes(report, 3) != null) {
-                    log.w("the car said it took its screen back but still sends touches - showing ours again")
-                    onVideoFocus(VIDEO_FOCUS_PROJECTED)
-                }
-                Wire.bytes(report, 4)?.let(::onKeyEvent)
-                Wire.bytes(report, 6)?.let(::onRelativeEvent)
-                val touch = Wire.bytes(report, 3) ?: Wire.bytes(report, 7)
-                if (touch == null) {
-                    return
-                }
-                val touchFields = Wire.fields(touch)
-                val action = Wire.varint(touchFields, 3)?.toInt() ?: 0
-                val pointers = Wire.allBytes(touchFields, 1)
-                if (pointers.isEmpty()) return
-                val config = videoConfigs.getOrNull(selectedConfigIndex ?: 0)
-                val size = config?.pixelSize()
-                // The car crops its margin off the frame and measures taps from the corner of what
-                // it shows, so they come in short by half the margin: the 2024 VW (margin 240) sent
-                // y=6, which is inside the cropped band, and the Uconnect's never passed 351 on a
-                // 480-high frame with a 130 margin. Without this every tap landed 120 px too high
-                // and the VW couldn't press past its first screen.
-                val shift = config?.marginInsets() ?: Insets.NONE
-                val points = pointers.mapIndexedNotNull { index, pointer ->
-                    val fields = Wire.fields(pointer)
-                    val rawX = Wire.varint(fields, 1)?.toInt() ?: return@mapIndexedNotNull null
-                    val rawY = Wire.varint(fields, 2)?.toInt() ?: return@mapIndexedNotNull null
-                    val id = Wire.varint(fields, 3)?.toInt() ?: index
-                    TouchPoint(id, clamp(rawX + shift.left, size?.first), clamp(rawY + shift.top, size?.second))
-                }
-                if (points.isEmpty()) return
-                val actionIndex = (Wire.varint(touchFields, 2)?.toInt() ?: 0).coerceIn(0, points.size - 1)
-                if (points.size > 1 && touchesSeen < 3) {
-                    log.i("multi-touch: ${points.size} pointers, action=$action index=$actionIndex")
-                }
-
-                touchesSeen++
-                if (touchesSeen <= 10 || action == ACTION_DOWN || action == ACTION_UP) {
-                    val at = points[actionIndex]
-                    log.i("<- Touch action=$action at (${at.x.toInt()},${at.y.toInt()}) pointers=${points.size}")
-                }
-                // Time the next frame against this tap: see [reportTouchLatency].
-                if (action == ACTION_DOWN || action == ACTION_UP) touchAtUs = System.nanoTime() / 1000
-                projection?.onTouch(action, actionIndex, points)
-            }
+            MSG_INPUT_REPORT -> onInputReport(body)
 
             else -> log.i("<- unhandled input message id=$messageId (${body.size} bytes)")
         }
     }
 
+    private fun onInputReport(body: ByteArray) {
+        val report = Wire.fields(body)
+        if (Wire.varint(report, 1) == null) return
+        Wire.bytes(report, 4)?.let(::onKeyEvent)
+        Wire.bytes(report, 6)?.let(::onRelativeEvent)
+        // Touchpads (field 7) need a separate gesture pipeline; their coordinates are not
+        // positions on the projected screen.
+        val touch = Wire.bytes(report, 3)
+        if (touch == null) {
+            return
+        }
+        // The 2018 Uconnect agrees to Exit but keeps showing our last frame and sending
+        // touches, which looked like a crash. A touch means our screen is still up there.
+        if (videoStarted && !videoProjected) {
+            log.w("the car said it took its screen back but still sends touches - showing ours again")
+            onVideoFocus(VIDEO_FOCUS_PROJECTED)
+        }
+        val config = videoConfigs.getOrNull(selectedConfigIndex ?: 0)
+        // The car crops its margin off the frame and measures taps from the corner of what it
+        // shows, so they come in short by half the margin: the 2024 VW (margin 240) sent y=6,
+        // inside the cropped band, and the Uconnect's never passed 351 on a 480-high frame with a
+        // 130 margin. Without this every tap landed 120 px too high.
+        val shift = config?.let(::marginsFor) ?: Insets.NONE
+        val size = config?.pixelSize()
+        // A stretched frame (see [screenShape]): the car's tap is on the frame, the UI is drawn smaller.
+        val drawn = drawSize
+        val stretched = drawn != null && size != null
+        val (action, actionIndex, raw) =
+            (if (stretched) InputProtocol.touch(touch, size) else InputProtocol.touch(touch, size, shift.left, shift.top)) ?: return
+        val points = if (drawn != null && size != null) {
+            raw.map { TouchPoint(it.id, it.x * drawn.first / size.first, it.y * drawn.second / size.second) }
+        } else {
+            raw
+        }
+        if (points.size > 1 && touchesSeen < 3) {
+            log.i("multi-touch: ${points.size} pointers, action=$action index=$actionIndex")
+        }
+
+        touchesSeen++
+        if (touchesSeen <= 10 || action == ACTION_DOWN || action == ACTION_UP) {
+            val at = points[actionIndex]
+            log.i("<- Touch action=$action at (${at.x.toInt()},${at.y.toInt()}) pointers=${points.size}")
+        }
+        // Time the next frame against this tap: see [reportTouchLatency].
+        if (action == ACTION_DOWN || action == ACTION_UP) touchAtUs = System.nanoTime() / 1000
+        projection?.onTouch(action, actionIndex, points)
+    }
+
     /**
      * Asks the head unit to forward its buttons. Many units send nothing from the steering wheel
      * until the phone names the keys it wants. What the unit offered is asked for; a unit that
@@ -967,6 +1018,37 @@ class GearslipRunner(
         return wide.minByOrNull(::pixels) ?: known.maxByOrNull(::pixels)
     }
 
+    /**
+     * The part of a [frameWidth] x [frameHeight] frame shaped like the screen size set in
+     * Settings, centred and in even pixels; null when none is set or it is the frame's own shape.
+     * Some head units report the wrong size, then crop or squash the frame onto their real screen.
+     */
+    private fun screenShape(frameWidth: Int, frameHeight: Int): Pair<Int, Int>? {
+        val screen = CarSettings.screenSize.value ?: return null
+        val wider = screen.width.toLong() * frameHeight >= screen.height.toLong() * frameWidth
+        val shape = if (wider) {
+            frameWidth to (frameWidth.toLong() * screen.height / screen.width).toInt()
+        } else {
+            (frameHeight.toLong() * screen.width / screen.height).toInt() to frameHeight
+        }
+        val even = (shape.first / 2 * 2).coerceAtLeast(2) to (shape.second / 2 * 2).coerceAtLeast(2)
+        return even.takeIf { it != (frameWidth to frameHeight) }
+    }
+
+    /**
+     * The strips of the frame the car doesn't show: the head unit's own margins, or, when a screen
+     * size is set to crop, whatever lies outside [screenShape]. The UI keeps out of them and taps
+     * are measured from inside them.
+     */
+    private fun marginsFor(config: ServiceDiscovery.VideoConfig): Insets {
+        val (width, height) = config.pixelSize() ?: return config.marginInsets()
+        if (CarSettings.screenFit.value != ScreenFit.CROP) return config.marginInsets()
+        val (w, h) = screenShape(width, height) ?: return config.marginInsets()
+        val sideX = width - w
+        val sideY = height - h
+        return Insets(top = sideY / 2, bottom = sideY - sideY / 2, left = sideX / 2, right = sideX - sideX / 2)
+    }
+
     private fun startVideoSource() {
         lastKeyframeSentAt = System.currentTimeMillis() // frame #1 is always a keyframe
         val index = selectedConfigIndex ?: 0
@@ -987,18 +1069,37 @@ class GearslipRunner(
         log.i("-> Start(session_id=$SESSION_ID, configuration_index=$index -> $config)")
         // The car crops its margins off the frame, so keep the UI out of them unless a vehicle
         // profile has its own tuned insets.
-        if (vehicleProfile?.insets.let { it == null || it == Insets.NONE }) {
-            val insets = config.marginInsets()
+        stretcher?.release()
+        stretcher = null
+        drawSize = null
+        val shape = screenShape(width, height)
+        val squash = shape != null && CarSettings.screenFit.value == ScreenFit.SQUASH
+        if (shape != null) {
+            log.i(
+                "screen size set to ${CarSettings.screenSize.value} in Settings: " +
+                    "${if (squash) "drawing" else "cropping to"} ${shape.first}x${shape.second} of the ${width}x$height frame",
+            )
+        }
+        if (squash) {
+            CarEnvironment.setInsets(Insets.NONE)
+        } else if (vehicleProfile?.insets.let { it == null || it == Insets.NONE }) {
+            val insets = marginsFor(config)
             CarEnvironment.setInsets(insets)
             if (insets != Insets.NONE) log.i("keeping the UI clear of the car's margins: $insets")
         }
 
         val useProjection = projection != null
+        // 60fps only over a cable: over Wi-Fi it doubles the data for little the driver sees.
+        videoFrameRate = if (config.frameRate == 1 && !wireless) 60 else 30
+        smoothWindows = 0
+        lastCut = null
+        decoderBound = false
+        adaptiveVideo = CarSettings.experimentalFeaturesEnabled.value && CarSettings.adaptiveVideoEnabled.value
+        if (adaptiveVideo) log.i("video: adaptive bitrate on (experimental)")
         videoSource = VideoSource(
             width = width,
             height = height,
-            // 60fps only over a cable: over Wi-Fi it doubles the data for little the driver sees.
-            frameRate = if (config.frameRate == 1 && !wireless) 60 else 30,
+            frameRate = videoFrameRate,
             mode = if (useProjection) VideoSource.Mode.SURFACE else VideoSource.Mode.TEST_CARD,
             wireless = wireless,
             onCodecConfig = { csd ->
@@ -1015,7 +1116,16 @@ class GearslipRunner(
                 source.start()
                 val surface = source.inputSurface
                 if (projection != null && surface != null) {
-                    projection.onSurfaceReady(surface, width, height, config.density)
+                    val stretch = shape?.takeIf { squash }?.let { (w, h) ->
+                        FrameStretcher(surface, w, h, width, height).takeIf { it.start() }
+                    }
+                    stretcher = stretch
+                    if (stretch != null) {
+                        drawSize = stretch.width to stretch.height
+                        projection.onSurfaceReady(stretch.input, stretch.width, stretch.height, config.density)
+                    } else {
+                        projection.onSurfaceReady(surface, width, height, config.density)
+                    }
                     SessionStatus.projecting()
                     BluetoothAudioCheck.onProjecting()
                     LocationCheck.onProjecting()
@@ -1156,18 +1266,15 @@ class GearslipRunner(
         log.i("touch -> frame: ${draw + encode}ms (draw ${draw}ms, encode and wait ${encode}ms)")
     }
 
-    private fun clamp(value: Int, limit: Int?): Float = when {
-        limit == null -> value.toFloat()
-        value < 0 -> 0f
-        value >= limit -> (limit - 1).toFloat()
-        else -> value.toFloat()
-    }
-
     private fun onPingRequest(body: ByteArray) {
         // The timestamp is an int64 and has to come back unchanged. Read as an int32 it was cut
         // short, and a car that checks the echo (an Audi MIB2+) gave up at its second ping.
-        val timestamp = Protobuf.readInt64Field(body, 1) ?: System.nanoTime()
-        send(MSG_PING_RESPONSE, Protobuf.varintField(1, timestamp), encrypted = tls.handshakeComplete)
+        val fields = Wire.fields(body)
+        val timestamp = Wire.varint(fields, 1) ?: return
+        val payload = Wire.bytes(fields, 3)
+        val response = Protobuf.varintField(1, timestamp) +
+            (payload?.let { Protobuf.bytesField(2, it) } ?: byteArrayOf())
+        send(MSG_PING_RESPONSE, response, encrypted = tls.handshakeComplete)
         log.i("<- PingRequest(timestamp=$timestamp) / -> PingResponse (keeping the session alive)")
     }
 
@@ -1189,41 +1296,16 @@ class GearslipRunner(
         try {
             writer.execute {
                 try {
-                    if (payload.size <= Frames.MAX_FRAME_PAYLOAD) {
-                        val framePayload = if (encrypted) tls.encrypt(payload) else payload
-                        output.write(Frames.build(channel, encrypted, framePayload, messageType))
-                    } else {
-                        // Split exactly as aasdk does: chunk the *plaintext*, encrypt each chunk
-                        // separately, and carry the total plaintext length in the FIRST frame.
-                        // Video keyframes for anything busier than a test card exceed 16 KB routinely.
-                        var offset = 0
-                        while (offset < payload.size) {
-                            val size = minOf(Frames.MAX_FRAME_PAYLOAD, payload.size - offset)
-                            val chunk = payload.copyOfRange(offset, offset + size)
-                            val frameType = when {
-                                offset == 0 -> Frames.TYPE_FIRST
-                                offset + size >= payload.size -> Frames.TYPE_LAST
-                                else -> Frames.TYPE_MIDDLE
-                            }
-                            val framePayload = if (encrypted) tls.encrypt(chunk) else chunk
-                            output.write(
-                                Frames.build(
-                                    channel, encrypted, framePayload, messageType, frameType,
-                                    if (frameType == Frames.TYPE_FIRST) payload.size else null,
-                                ),
-                            )
-                            offset += size
-                        }
-                        splitMessages++
-                    }
+                    val frameCount = Frames.writeMessage(output, channel, encrypted, messageType, payload) { tls.encrypt(it) }
+                    if (frameCount > 1) splitMessages++
                     output.flush()
-                } catch (e: java.io.IOException) {
+                } catch (e: IOException) {
                     if (running) log.w("send failed, stopping: ${e.message}")
                     running = false
                     videoSource?.stop()
                 }
             }
-        } catch (e: java.util.concurrent.RejectedExecutionException) {
+        } catch (e: RejectedExecutionException) {
             // The session is over; nothing more goes out.
         }
     }
@@ -1302,8 +1384,10 @@ class GearslipRunner(
                     SessionReport.stream("${"%.1f".format(fps)} fps, sent=$sent acked=$acksSeen")
                     log.i(
                         "video: ${"%.1f".format(fps)} fps over 5s | sent=$sent waited=${waited}ms " +
-                            "acked=$acksSeen inFlight=$inFlight split=$splitMessages",
+                            "acked=$acksSeen inFlight=$inFlight split=$splitMessages " +
+                            "kbps=${(videoSource?.bitRate ?: 0) / 1000}",
                     )
+                    adaptBitRate(fps, waited)
 
                     // Self-healing safety net: force a fresh keyframe periodically regardless
                     // of whether we think one is owed. Protects against any future case where
@@ -1318,13 +1402,65 @@ class GearslipRunner(
         }.apply { isDaemon = true }.start()
     }
 
+    /** The frame rate the stream was set up for, which adaptive bitrate measures against. */
+    @Volatile private var videoFrameRate = 30
+
+    /** Five-second windows in a row the stream kept up, towards climbing back up. */
+    private var smoothWindows = 0
+    /** The bitrate and frame rate before the last cut, to see whether cutting helped. */
+    private var lastCut: Pair<Int, Double>? = null
+    /** Experimental: read once per stream, so flipping the switch mid-drive changes nothing. */
+    @Volatile private var adaptiveVideo = false
+    /** Set once a cut didn't help: this car's decoder, not the link, sets the pace. */
+    private var decoderBound = false
+
+    /**
+     * Adaptive bitrate. A window where the encoder spent most of its time held back by the
+     * car's acks while the frame rate sagged means the car, or the Wi-Fi to it, can't take
+     * frames this size: a quarter comes off. Two easy windows in a row put a tenth back, up to
+     * where the stream started. A still screen (few frames, no waiting) changes nothing.
+     */
+    private fun adaptBitRate(fps: Double, waitedMs: Long) {
+        if (!adaptiveVideo) return
+        val source = videoSource ?: return
+        val target = videoFrameRate.toDouble()
+        val behind = waitedMs > ADAPT_WINDOW_MS / 2 && fps < target * 0.8
+        val easy = waitedMs < ADAPT_WINDOW_MS / 10
+        when {
+            behind && !decoderBound -> {
+                smoothWindows = 0
+                val cut = lastCut
+                if (cut != null && fps < cut.second * 1.05) {
+                    // The last cut bought no frames: the car's decoder is the limit, not the
+                    // link, and smaller frames would only look worse. Undo it and stop here.
+                    decoderBound = true
+                    source.setBitRate(cut.first)
+                    log.i("video: a lower bitrate didn't help the car keep up - back to ${cut.first / 1000} kbps, adapting off")
+                    return
+                }
+                val before = source.bitRate
+                source.setBitRate((before * 0.75).toInt())
+                if (source.bitRate != before) {
+                    lastCut = before to fps
+                    log.i("video: car falling behind - bitrate ${before / 1000} -> ${source.bitRate / 1000} kbps")
+                }
+            }
+            easy && source.bitRate < source.fullBitRate -> {
+                lastCut = null
+                if (++smoothWindows >= 2) {
+                    smoothWindows = 0
+                    val before = source.bitRate
+                    source.setBitRate((before * 1.1).toInt() + 1)
+                    log.i("video: keeping up - bitrate ${before / 1000} -> ${source.bitRate / 1000} kbps")
+                }
+            }
+            else -> smoothWindows = 0
+        }
+    }
+
     private companion object {
-        /**
-         * The protocol version Gearslip answers every car with, as (major, minor), or null to echo
-         * the head unit's. Kept at 1.3 because every working car was tested with it; see
-         * onVersionRequest.
-         */
-        val CLAIM_VERSION: Pair<Int, Int>? = 1 to 3
+        /** The stats window adaptive bitrate reads, matching the watchdog's sleep. */
+        const val ADAPT_WINDOW_MS = 5_000L
 
         // protobuf/aap_protobuf/service/control/ControlMessageType.proto:7-17
         const val MSG_VERSION_REQUEST = 1
@@ -1338,6 +1474,8 @@ class GearslipRunner(
         const val MSG_BYEBYE_REQUEST = 15
         const val MSG_BYEBYE_RESPONSE = 16
         const val MSG_VOICE_SESSION_NOTIFICATION = 17
+        const val MSG_UNEXPECTED_MESSAGE = 255
+        const val MSG_FRAMING_ERROR = 65535
         const val MSG_CHANNEL_OPEN_REQUEST = 7
         const val MSG_CHANNEL_OPEN_RESPONSE = 8
 

gearslip/src/main/java/app/seb3thehacker/gearslip/PermissionActivity.kt

@@ -0,0 +1,49 @@
+package app.seb3thehacker.gearslip
+
+import android.app.Activity
+import android.app.ActivityOptions
+import android.content.Context
+import android.content.Intent
+import android.os.Bundle
+import android.view.Display
+
+/**
+ * Asks for runtime permissions on the phone's own screen, for a car screen that can't show
+ * Android's dialog itself. It has no look of its own: the dialog appears, the answer is given,
+ * and it finishes.
+ */
+class PermissionActivity : Activity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        val wanted = intent.getStringArrayExtra(EXTRA_PERMISSIONS)
+            ?.filter { checkSelfPermission(it) != android.content.pm.PackageManager.PERMISSION_GRANTED }
+            .orEmpty()
+        if (wanted.isEmpty() || savedInstanceState != null) {
+            if (wanted.isEmpty()) finish()
+            return
+        }
+        requestPermissions(wanted.toTypedArray(), REQUEST)
+    }
+
+    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {
+        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
+        GearslipLog.i("permissions: ${permissions.zip(grantResults.toList()).joinToString { (p, r) -> "${p.substringAfterLast('.')}=${r == 0}" }}")
+        finish()
+    }
+
+    companion object {
+        private const val EXTRA_PERMISSIONS = "permissions"
+        private const val REQUEST = 1
+
+        /** Shows the permission dialog on the phone, whichever screen [context] belongs to. */
+        fun ask(context: Context, permissions: Array<String>) {
+            val intent = Intent(context, PermissionActivity::class.java)
+                .putExtra(EXTRA_PERMISSIONS, permissions)
+                .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+            val options = ActivityOptions.makeBasic().setLaunchDisplayId(Display.DEFAULT_DISPLAY)
+            runCatching { context.startActivity(intent, options.toBundle()) }
+                .onFailure { GearslipLog.w("permissions: could not ask on the phone: ${it.message}") }
+        }
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/PhoneTls.kt

@@ -1,5 +1,6 @@
 package app.seb3thehacker.gearslip
 
+import java.io.ByteArrayOutputStream
 import java.net.Socket
 import java.nio.ByteBuffer
 import java.security.KeyStore
@@ -11,23 +12,10 @@ import javax.net.ssl.SSLEngine
 import javax.net.ssl.SSLEngineResult
 import javax.net.ssl.SSLEngineResult.HandshakeStatus
 import javax.net.ssl.SSLPeerUnverifiedException
+import javax.net.ssl.SSLException
 import javax.net.ssl.X509ExtendedTrustManager
 
-/**
- * The phone end of the Android Auto TLS session.
- *
- * Two things here are the opposite of what aasdk does, because aasdk implements the head
- * unit and the head unit is the TLS *client*: it calls TLS_client_method() and
- * SSL_set_connect_state (src/Transport/SSLWrapper.cpp:97-140, src/Messenger/Cryptor.cpp:87),
- * and SSL_set_accept_state appears nowhere in that codebase. So the phone is the TLS
- * **server** and its certificate goes out as the server certificate - sent unconditionally
- * on every handshake, which is precisely what we are testing.
- *
- * TLS here is not layered over the socket: handshake bytes travel inside
- * MESSAGE_ENCAPSULATED_SSL control messages (id 3). That rules out SSLSocket and makes
- * SSLEngine - a buffer-to-buffer engine, the JSSE counterpart of aasdk's memory BIO pair -
- * the right tool.
- */
+/** TLS server for projection. Handshake records travel in control message 3, not a TLS socket. */
 class PhoneTls(keyStore: KeyStore, password: CharArray) {
     private val log = GearslipLog.tagged("TLS")
 
@@ -36,7 +24,7 @@ class PhoneTls(keyStore: KeyStore, password: CharArray) {
     private var appBuffer = ByteBuffer.allocate(32 * 1024)
     private var netBuffer = ByteBuffer.allocate(32 * 1024)
 
-    var handshakeComplete: Boolean = false
+    @Volatile var handshakeComplete: Boolean = false
         private set
 
     init {
@@ -52,6 +40,7 @@ class PhoneTls(keyStore: KeyStore, password: CharArray) {
             useClientMode = false
             // want, not need: we ask the head unit for its certificate so the run also tells
             // us what real units present, but we never make the session depend on getting one.
+            // Homemade head units may have none.
             wantClientAuth = true
             enabledProtocols = arrayOf("TLSv1.2") // aasdk pins TLS 1.2
         }
@@ -88,7 +77,7 @@ class PhoneTls(keyStore: KeyStore, password: CharArray) {
                     if (netBuffer.hasRemaining()) {
                         outgoing += ByteArray(netBuffer.remaining()).also { netBuffer.get(it) }
                     }
-                    if (result.status == SSLEngineResult.Status.CLOSED) break@loop
+                    if (result.status == SSLEngineResult.Status.CLOSED) throw SSLException("TLS closed during handshake")
                 }
 
                 HandshakeStatus.NEED_UNWRAP -> {
@@ -100,7 +89,7 @@ class PhoneTls(keyStore: KeyStore, password: CharArray) {
                             appBuffer = ByteBuffer.allocate(appBuffer.capacity() * 2)
                             continue@loop
                         }
-                        SSLEngineResult.Status.CLOSED -> break@loop
+                        SSLEngineResult.Status.CLOSED -> throw SSLException("TLS closed during handshake")
                         else -> Unit
                     }
                 }
@@ -124,7 +113,7 @@ class PhoneTls(keyStore: KeyStore, password: CharArray) {
     /** Wraps a control-channel payload for an ENCRYPTED frame. */
     fun encrypt(plain: ByteArray): ByteArray {
         val source = ByteBuffer.wrap(plain)
-        val out = java.io.ByteArrayOutputStream()
+        val out = ByteArrayOutputStream()
         while (source.hasRemaining()) {
             netBuffer.clear()
             val result = engine.wrap(source, netBuffer)
@@ -132,6 +121,9 @@ class PhoneTls(keyStore: KeyStore, password: CharArray) {
                 netBuffer = ByteBuffer.allocate(netBuffer.capacity() * 2)
                 continue
             }
+            if (result.status != SSLEngineResult.Status.OK || result.bytesConsumed() == 0) {
+                throw SSLException("TLS could not encrypt application data: ${result.status}")
+            }
             netBuffer.flip()
             val chunk = ByteArray(netBuffer.remaining())
             netBuffer.get(chunk)
@@ -140,14 +132,10 @@ class PhoneTls(keyStore: KeyStore, password: CharArray) {
         return out.toByteArray()
     }
 
-    /**
-     * Unwraps one ENCRYPTED frame's payload. aasdk decrypts per frame
-     * (MessageOutStream::compoundFrame encrypts per frame), so each frame's payload is
-     * self-contained ciphertext.
-     */
+    /** Each encrypted projection frame contains complete TLS records. */
     fun decrypt(cipher: ByteArray): ByteArray {
         val source = ByteBuffer.wrap(cipher)
-        val out = java.io.ByteArrayOutputStream()
+        val out = ByteArrayOutputStream()
         while (source.hasRemaining()) {
             appBuffer.clear()
             val result = engine.unwrap(source, appBuffer)
@@ -157,10 +145,9 @@ class PhoneTls(keyStore: KeyStore, password: CharArray) {
                     continue
                 }
                 SSLEngineResult.Status.BUFFER_UNDERFLOW -> {
-                    log.w("decrypt: record split across frames (${source.remaining()} bytes left over)")
-                    break
+                    throw SSLException("Incomplete TLS record in an encrypted frame")
                 }
-                SSLEngineResult.Status.CLOSED -> break
+                SSLEngineResult.Status.CLOSED -> throw SSLException("TLS peer closed the connection")
                 else -> Unit
             }
             appBuffer.flip()

gearslip/src/main/java/app/seb3thehacker/gearslip/Protobuf.kt

@@ -2,14 +2,7 @@ package app.seb3thehacker.gearslip
 
 import java.io.ByteArrayOutputStream
 
-/**
- * Just enough protobuf to run the spike, hand-rolled so there is no protoc step.
- *
- * Only three messages are ever written (AuthResponse is only read):
- *   ServiceDiscoveryRequest { optional string label_text = 4; optional string device_name = 5; }
- *   PingResponse            { required int64 timestamp = 1; }
- *   AuthResponse            { required int32 status = 1; }
- */
+/** Protobuf field encoding and diagnostic rendering for the projection protocol. */
 object Protobuf {
 
     fun varint(value: Long): ByteArray {
@@ -41,29 +34,7 @@ object Protobuf {
     fun readInt32Field(data: ByteArray, field: Int): Int? = readInt64Field(data, field)?.toInt()
 
     /** Reads a varint field whole, for int64s such as a ping's timestamp. */
-    fun readInt64Field(data: ByteArray, field: Int): Long? {
-        var pos = 0
-        while (pos < data.size) {
-            val (tag, afterTag) = readVarint(data, pos) ?: return null
-            pos = afterTag
-            val number = (tag ushr 3).toInt()
-            when ((tag and 7L).toInt()) {
-                0 -> {
-                    val (value, afterValue) = readVarint(data, pos) ?: return null
-                    pos = afterValue
-                    if (number == field) return value
-                }
-                2 -> {
-                    val (len, afterLen) = readVarint(data, pos) ?: return null
-                    pos = afterLen + len.toInt()
-                }
-                5 -> pos += 4
-                1 -> pos += 8
-                else -> return null
-            }
-        }
-        return null
-    }
+    fun readInt64Field(data: ByteArray, field: Int): Long? = Wire.varint(Wire.fields(data), field)
 
     /**
      * Shallow field dump. Used on ServiceDiscoveryResponse: its make/model/year strings
@@ -71,6 +42,7 @@ object Protobuf {
      * proof that the session is live and we are decrypting correctly.
      */
     fun describe(data: ByteArray, indent: String = "  "): String {
+        if (indent.length > 32) return "$indent(nested message)\n"
         val sb = StringBuilder()
         var pos = 0
         while (pos < data.size) {
@@ -89,6 +61,7 @@ object Protobuf {
                 }
                 2 -> {
                     val (len, afterLen) = readVarint(data, pos) ?: break
+                    if (len < 0 || len > data.size - afterLen) break
                     val end = afterLen + len.toInt()
                     if (end > data.size) break
                     val body = data.copyOfRange(afterLen, end)
@@ -117,6 +90,7 @@ object Protobuf {
         var pos = start
         while (pos < data.size && shift <= 63) {
             val b = data[pos].toInt() and 0xFF
+            if (shift == 63 && b > 1) return null
             result = result or ((b and 0x7F).toLong() shl shift)
             pos++
             if (b and 0x80 == 0) return result to pos
@@ -135,45 +109,68 @@ object Wire {
         val out = mutableListOf<Field>()
         var pos = 0
         while (pos < data.size) {
-            val tag = readVarint(data, pos) ?: break
+            val tag = readVarint(data, pos) ?: return emptyList()
             pos = tag.second
             val number = (tag.first ushr 3).toInt()
+            if (tag.first ushr 3 !in 1..0x1fff_ffffL) return emptyList()
             when ((tag.first and 7L).toInt()) {
                 0 -> {
-                    val v = readVarint(data, pos) ?: break
+                    val v = readVarint(data, pos) ?: return emptyList()
                     pos = v.second
                     out += Field(number, 0, v.first, null)
                 }
-                1 -> { if (pos + 8 > data.size) break; pos += 8 }
+                1 -> { if (data.size - pos < 8) return emptyList(); pos += 8 }
                 2 -> {
-                    val len = readVarint(data, pos) ?: break
+                    val len = readVarint(data, pos) ?: return emptyList()
+                    if (len.first < 0 || len.first > data.size - len.second) return emptyList()
                     val end = len.second + len.first.toInt()
-                    if (end > data.size || end < len.second) break
+                    if (end > data.size || end < len.second) return emptyList()
                     out += Field(number, 2, 0, data.copyOfRange(len.second, end))
                     pos = end
                 }
-                5 -> { if (pos + 4 > data.size) break; pos += 4 }
-                else -> break
+                5 -> { if (data.size - pos < 4) return emptyList(); pos += 4 }
+                else -> return emptyList()
             }
         }
         return out
     }
 
     fun varint(fields: List<Field>, number: Int): Long? =
-        fields.firstOrNull { it.number == number && it.wireType == 0 }?.varint
+        fields.lastOrNull { it.number == number && it.wireType == 0 }?.varint
 
     fun bytes(fields: List<Field>, number: Int): ByteArray? =
-        fields.firstOrNull { it.number == number && it.wireType == 2 }?.bytes
+        fields.lastOrNull { it.number == number && it.wireType == 2 }?.bytes
 
     fun allBytes(fields: List<Field>, number: Int): List<ByteArray> =
         fields.filter { it.number == number && it.wireType == 2 }.mapNotNull { it.bytes }
 
+    /** Protobuf readers accept both packed and unpacked repeated numeric fields. */
+    fun repeatedInts(fields: List<Field>, number: Int): List<Int> =
+        repeatedLongs(fields, number)?.map(Long::toInt).orEmpty()
+
+    /** Null means a packed field contained an incomplete or overflowing varint. */
+    fun repeatedLongs(fields: List<Field>, number: Int): List<Long>? = buildList {
+        for (field in fields.filter { it.number == number }) {
+            if (field.wireType == 0) add(field.varint)
+            else if (field.wireType == 2) {
+                val bytes = field.bytes ?: continue
+                var position = 0
+                while (position < bytes.size) {
+                    val (value, next) = readVarint(bytes, position) ?: return null
+                    add(value)
+                    position = next
+                }
+            }
+        }
+    }
+
     private fun readVarint(data: ByteArray, start: Int): Pair<Long, Int>? {
         var result = 0L
         var shift = 0
         var pos = start
         while (pos < data.size && shift <= 63) {
             val b = data[pos].toInt() and 0xFF
+            if (shift == 63 && b > 1) return null
             result = result or ((b and 0x7F).toLong() shl shift)
             pos++
             if (b and 0x80 == 0) return result to pos

gearslip/src/main/java/app/seb3thehacker/gearslip/ProtocolVersion.kt

@@ -0,0 +1,17 @@
+package app.seb3thehacker.gearslip
+
+/**
+ * Advertises our supported 1.x version, as Android Auto does for older head units. Head units that
+ * offer a newer major version (LIVI asks for 6.1, a RAV4 and the DHU for 4.2) still accept a 1.x
+ * answer, so only a major version of 0 is refused.
+ */
+internal object ProtocolVersion {
+    data class Response(val major: Int, val minor: Int, val supported: Boolean) {
+        val bytes: ByteArray get() = byteArrayOf(
+            (major ushr 8).toByte(), major.toByte(), (minor ushr 8).toByte(), minor.toByte(),
+            if (supported) 0 else -1, if (supported) 0 else -1,
+        )
+    }
+
+    fun respond(major: Int, minor: Int): Response = Response(1, 7, major >= 1 && minor in 0..0xffff)
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/ScreenProjector.kt

@@ -51,7 +51,7 @@ class ScreenProjector(private val context: Context) {
      * preview passes "gearslip-preview".
      */
     fun start(
-        surface: Surface,
+        surface: Surface?,
         width: Int,
         height: Int,
         densityDpi: Int,
@@ -219,6 +219,14 @@ class ScreenProjector(private val context: Context) {
         target.dispatchKeyEvent(event)
     }
 
+    /**
+     * Points the display at another surface, or none, without restarting what it shows. The
+     * preview's SurfaceView comes and goes as the phone turns; the car UI on it carries on.
+     */
+    fun setSurface(surface: Surface?) {
+        virtualDisplay?.surface = surface
+    }
+
     fun stop() {
         runCatching { presentation?.dismiss() }
         runCatching { owner?.destroy() }

gearslip/src/main/java/app/seb3thehacker/gearslip/ServiceDiscovery.kt

@@ -76,7 +76,7 @@ object ServiceDiscovery {
     fun findAudioServices(response: ByteArray): List<AudioService> = buildList {
         for (channel in Wire.allBytes(Wire.fields(response), 1)) {
             val service = Wire.fields(channel)
-            val id = Wire.varint(service, 1)?.toInt() ?: continue
+            val id = serviceId(service) ?: continue
             val sink = Wire.bytes(service, 3) ?: continue
             val sinkFields = Wire.fields(sink)
             val audioConfigs = Wire.allBytes(sinkFields, 3)
@@ -116,13 +116,26 @@ object ServiceDiscovery {
      */
     fun findMediaStatusChannel(response: ByteArray): Int? = findChannelWith(response, 9)
 
-    /** The instrument cluster's turn-by-turn channel (NavigationStatusService, Service field 8). */
-    fun findNavStatusChannel(response: ByteArray): Int? = findChannelWith(response, 8)
+    class NavStatusService(val serviceId: Int, val minimumIntervalMs: Int)
+
+    /** The cluster advertises its minimum update interval in NavigationStatusService field 1. */
+    fun findNavStatusService(response: ByteArray): NavStatusService? =
+        Wire.allBytes(Wire.fields(response), 1).firstNotNullOfOrNull { channel ->
+            val service = Wire.fields(channel)
+            val id = serviceId(service) ?: return@firstNotNullOfOrNull null
+            val navigation = Wire.bytes(service, 8) ?: return@firstNotNullOfOrNull null
+            val interval = Wire.varint(Wire.fields(navigation), 1) ?: return@firstNotNullOfOrNull null
+            if (interval !in 0L..Int.MAX_VALUE.toLong()) return@firstNotNullOfOrNull null
+            NavStatusService(id, interval.toInt())
+        }
+
+    private fun serviceId(fields: List<Wire.Field>): Int? =
+        Wire.varint(fields, 1)?.takeIf { it in 1L..255L }?.toInt()
 
     private fun findChannelWith(response: ByteArray, serviceField: Int): Int? =
         Wire.allBytes(Wire.fields(response), 1).firstNotNullOfOrNull { channel ->
             val service = Wire.fields(channel)
-            if (service.any { it.number == serviceField }) Wire.varint(service, 1)?.toInt() else null
+            if (Wire.bytes(service, serviceField) != null) serviceId(service) else null
         }
 
     /**
@@ -134,7 +147,7 @@ object ServiceDiscovery {
     fun findMicService(response: ByteArray): AudioService? {
         for (channel in Wire.allBytes(Wire.fields(response), 1)) {
             val service = Wire.fields(channel)
-            val id = Wire.varint(service, 1)?.toInt() ?: continue
+            val id = serviceId(service) ?: continue
             val source = Wire.fields(Wire.bytes(service, 5) ?: continue)
             val f = Wire.fields(Wire.bytes(source, 2) ?: continue)
             return AudioService(
@@ -179,9 +192,7 @@ object ServiceDiscovery {
             val fields = Wire.fields(Wire.bytes(service, 6) ?: continue)
             val address = Wire.bytes(fields, 1)?.let { String(it, Charsets.UTF_8) } ?: continue
             // Packed as declared, though a car may send each method as its own varint.
-            val methods = fields.filter { it.number == 2 }.flatMap { f ->
-                f.bytes?.let(::packedVarints) ?: listOf(f.varint.toInt())
-            }
+            val methods = Wire.repeatedInts(fields, 2)
             return BluetoothService(id, address, methods)
         }
         return null
@@ -215,8 +226,8 @@ object ServiceDiscovery {
      *                         repeated TouchScreen touchscreen = 2; ... }
      *   TouchScreen { required int32 width = 1; required int32 height = 2; type = 3; }
      *
-     * Touch coordinates arrive in this space (1258x708 on the 2018 Uconnect) and must be
-     * scaled to the projected video size before injection. [keycodesSupported] is what the
+     * Touch reports use projected video coordinates; these dimensions describe the input
+     * hardware and help select a video configuration. [keycodesSupported] is what the
      * head unit says it will actually send over the Input channel as key events (steering-wheel
      * buttons, etc.) - not every unit reports the same set, so it's kept for diagnostics and to
      * know ahead of time whether a button like voice/PTT is even wired up on this hardware.
@@ -245,38 +256,18 @@ object ServiceDiscovery {
     private fun inputServices(response: ByteArray): List<InputService> = buildList {
         for (channel in Wire.allBytes(Wire.fields(response), 1)) {
             val service = Wire.fields(channel)
-            val id = Wire.varint(service, 1)?.toInt() ?: continue
+            val id = serviceId(service) ?: continue
             val input = Wire.bytes(service, 4) ?: continue
             val inputFields = Wire.fields(input)
             // A unit with only a knob and buttons has no touchscreen entry; it still has keys.
             val touchFields = Wire.bytes(inputFields, 2)?.let { Wire.fields(it) }.orEmpty()
             val width = Wire.varint(touchFields, 1)?.toInt() ?: 0
             val height = Wire.varint(touchFields, 2)?.toInt() ?: 0
-            // Declared packed, but some units send each keycode as its own field.
-            val keycodes = inputFields.filter { it.number == 1 }.flatMap { f ->
-                f.bytes?.let(::packedVarints) ?: listOf(f.varint.toInt())
-            }
+            val keycodes = Wire.repeatedInts(inputFields, 1)
             add(InputService(id, width, height, keycodes, Wire.varint(inputFields, 5)?.toInt() ?: 0))
         }
     }
 
-    /** Decodes a `[packed=true]` repeated varint field's raw bytes into individual values. */
-    private fun packedVarints(data: ByteArray): List<Int> = buildList {
-        var pos = 0
-        while (pos < data.size) {
-            var result = 0L
-            var shift = 0
-            while (pos < data.size) {
-                val b = data[pos].toInt() and 0xFF
-                result = result or ((b and 0x7F).toLong() shl shift)
-                pos++
-                if (b and 0x80 == 0) break
-                shift += 7
-            }
-            add(result.toInt())
-        }
-    }
-
     /**
      * The main screen's video sink. A head unit with a second screen, such as LIVI with a
      * cluster display, offers a sink for each; the one without a display id (0) is the main one.
@@ -289,7 +280,7 @@ object ServiceDiscovery {
     private fun videoServices(response: ByteArray): List<VideoService> = buildList {
         for (channel in Wire.allBytes(Wire.fields(response), 1)) {
             val service = Wire.fields(channel)
-            val id = Wire.varint(service, 1)?.toInt() ?: continue
+            val id = serviceId(service) ?: continue
             val sink = Wire.bytes(service, 3) ?: continue
 
             val sinkFields = Wire.fields(sink)
@@ -316,16 +307,15 @@ object ServiceDiscovery {
      *   SensorSourceService { repeated Sensor sensors = 1; }
      *   Sensor { required SensorType sensor_type = 1; }
      *
-     * Field numbers for what actually rides inside each SensorEvent once subscribed are not
-     * pinned down here - unlike video/audio/input, there's no independent source to check them
-     * against, so [CarSensors] shows the raw decode instead of trusting a guessed field map.
+     * SensorBatch contains repeated messages in fields 1 through 22 matching these type ids.
+     * The vehicle data screen keeps their raw contents for diagnostics.
      */
     class SensorService(val serviceId: Int, val types: List<Int>)
 
     fun findSensorService(response: ByteArray): SensorService? {
         for (channel in Wire.allBytes(Wire.fields(response), 1)) {
             val service = Wire.fields(channel)
-            val id = Wire.varint(service, 1)?.toInt() ?: continue
+            val id = serviceId(service) ?: continue
             val sensorSource = Wire.bytes(service, 2) ?: continue
             val types = Wire.allBytes(Wire.fields(sensorSource), 1).mapNotNull {
                 Wire.varint(Wire.fields(it), 1)?.toInt()

gearslip/src/main/java/app/seb3thehacker/gearslip/TlsSelfTest.kt

@@ -4,33 +4,25 @@ import java.net.Socket
 import java.nio.ByteBuffer
 import java.security.SecureRandom
 import java.security.cert.X509Certificate
+import javax.net.ssl.KeyManagerFactory
 import javax.net.ssl.SSLContext
 import javax.net.ssl.SSLEngine
 import javax.net.ssl.SSLEngineResult
 import javax.net.ssl.SSLEngineResult.HandshakeStatus
 import javax.net.ssl.X509ExtendedTrustManager
 
-/**
- * Runs [PhoneTls] against an in-process TLS client and checks that a full handshake plus a
- * data round trip works.
- *
- * This exists because of one specific hazard: a bug in the certificate, the key manager or
- * the engine wiring produces a dead connection in the car that is indistinguishable from a
- * head unit rejecting us - and the whole point of the spike is a trustworthy go/no-go
- * signal. Run this on the bench first; if it passes, a failure in the car is about the head
- * unit, not about this code.
- */
+/** Checks mutual TLS and an encrypted data round trip with an in-process head-unit peer. */
 object TlsSelfTest {
     private val log = GearslipLog.tagged("TLS")
 
-    fun run(identity: CertProvider.Identity): Boolean {
+    fun run(identity: CertProvider.Identity, withClientCertificate: Boolean = true): Boolean {
         log.i("=== TLS self-test starting ===")
         log.i("cert source: ${identity.source}")
         log.i("  subject = ${identity.certificate.subjectX500Principal}")
         log.i("  issuer  = ${identity.certificate.issuerX500Principal}")
         return try {
             val server = PhoneTls(identity.keyStore, identity.password)
-            val client = Driver(clientEngine())
+            val client = Driver(clientEngine(withClientCertificate))
 
             var outbound = client.pump(null) // ClientHello
             var rounds = 0
@@ -49,8 +41,7 @@ object TlsSelfTest {
                 return false
             }
 
-            // Data round trip, exercising the same encrypt path the spike uses for
-            // ServiceDiscoveryRequest.
+            // Exercise the same encrypt path used by ServiceDiscoveryRequest.
             val plaintext = "gearslip round trip".toByteArray()
             val decrypted = client.decrypt(server.encrypt(plaintext))
             if (!decrypted.contentEquals(plaintext)) {
@@ -66,9 +57,15 @@ object TlsSelfTest {
         }
     }
 
-    private fun clientEngine(): SSLEngine {
+    private fun clientEngine(withCertificate: Boolean): SSLEngine {
         val context = SSLContext.getInstance("TLSv1.2")
-        context.init(null, arrayOf(TrustAll()), SecureRandom())
+        val keyManagers = if (withCertificate) {
+            val client = SelfSignedCert.generate(commonName = "Self-test head unit")
+            KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm()).apply {
+                init(client.keyStore, SelfSignedCert.PASSWORD)
+            }.keyManagers
+        } else null
+        context.init(keyManagers, arrayOf(TrustAll()), SecureRandom())
         return context.createSSLEngine().apply {
             useClientMode = true
             enabledProtocols = arrayOf("TLSv1.2")

gearslip/src/main/java/app/seb3thehacker/gearslip/VideoSource.kt

@@ -42,6 +42,14 @@ class VideoSource(
         private set
 
     private var codec: MediaCodec? = null
+
+    /** The bitrate the encoder started at, the most [setBitRate] ever goes back up to. */
+    var fullBitRate = 0
+        private set
+
+    /** What the encoder is asked for right now. */
+    @Volatile var bitRate = 0
+        private set
     private var worker: Thread? = null
     @Volatile private var running = false
     private var frameIndex = 0L
@@ -51,6 +59,8 @@ class VideoSource(
         val bitRate = defaultBitRate(width, height, frameRate, level).let {
             if (wireless) (it * WIRELESS_SHARE).toInt().coerceAtMost(WIRELESS_MAX_BIT_RATE) else it
         }
+        fullBitRate = bitRate
+        this.bitRate = bitRate
         fun format(tuned: Boolean) = MediaFormat.createVideoFormat(MIME, width, height).apply {
             setInteger(
                 MediaFormat.KEY_COLOR_FORMAT,
@@ -128,9 +138,28 @@ class VideoSource(
         }.onFailure { log.w("requestSyncFrame failed: ${it.message}") }
     }
 
+    /**
+     * Changes the bitrate while streaming, without a new keyframe or a restart. Used to back off
+     * when the car (or the Wi-Fi to it) can't keep up, and to climb back once it can.
+     */
+    fun setBitRate(bps: Int) {
+        val target = bps.coerceIn(fullBitRate / 4, fullBitRate)
+        if (target == bitRate) return
+        runCatching {
+            codec?.setParameters(Bundle().apply { putInt(MediaCodec.PARAMETER_KEY_VIDEO_BITRATE, target) })
+            bitRate = target
+        }.onFailure { log.w("setBitRate failed: ${it.message}") }
+    }
+
     fun stop() {
         running = false
-        worker?.join(1_000)
+        // Stop is called from threads that are themselves being shut down. An interrupt here
+        // used to escape as an uncaught exception and take the whole app down with the session.
+        try {
+            worker?.join(1_000)
+        } catch (e: InterruptedException) {
+            Thread.currentThread().interrupt()
+        }
         runCatching { inputSurface?.release() }
         inputSurface = null
         runCatching { codec?.stop() }

gearslip/src/main/java/app/seb3thehacker/gearslip/audio/AudioLink.kt

@@ -4,6 +4,8 @@ import app.seb3thehacker.gearslip.GearslipLog
 import app.seb3thehacker.gearslip.Protobuf
 import app.seb3thehacker.gearslip.ServiceDiscovery
 import app.seb3thehacker.gearslip.Wire
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.TimeUnit
 
 /**
  * The phone end of the head unit's media audio sink, the audio twin of the video channel:
@@ -25,7 +27,10 @@ class AudioLink(
     /** Log name: "audio" for the media sink, "guidance" for the directions sink. */
     private val tag: String = "audio",
     private val sessionId: Int = SESSION_ID,
-    /** Media asks the car for focus; directions just start, and the car ducks music under them. */
+    /**
+     * Media asks the car for focus when it starts. Directions ask only around each announcement,
+     * through [askForSpeakers], and only when the music isn't already ours.
+     */
     private val asksFocus: Boolean = true,
     private val onReady: (AudioLink) -> Unit = { CarAudio.attach(it) },
     private val onClose: (AudioLink) -> Unit = { CarAudio.detach(it) },
@@ -58,6 +63,47 @@ class AudioLink(
 
     val channelId get() = service.serviceId
 
+    /** Sending audio now, which for media means the car has handed us the speakers. */
+    val streaming get() = started
+
+    @Volatile private var holdsSpeakers = false
+    @Volatile private var focusAnswer: CountDownLatch? = null
+    @Volatile private var answerDueBy = 0L
+
+    /** True just after [askForSpeakers] or [handBackSpeakers], when the car's next focus answer is ours. */
+    fun expectsFocusAnswer() = System.currentTimeMillis() < answerDueBy
+
+    /**
+     * For directions when nothing of ours is playing, so the car's speakers belong to the radio
+     * or a Bluetooth phone. Android Auto asks for them before each announcement, letting the
+     * other source duck, and hands them back afterwards. Speaking without asking left a 2025
+     * Nissan's Bosch head unit rebooting mid-drive (issue #35).
+     *
+     * Waits briefly for the car's answer and speaks anyway without one, as some cars never answer.
+     */
+    fun askForSpeakers() {
+        if (holdsSpeakers) return
+        val answer = CountDownLatch(1)
+        focusAnswer = answer
+        answerDueBy = System.currentTimeMillis() + FOCUS_WAIT_MS
+        holdsSpeakers = true
+        sendControl(MSG_FOCUS_REQUEST, Protobuf.varintField(1, FOCUS_GAIN_TRANSIENT_MAY_DUCK.toLong()))
+        GearslipLog.i("$tag: -> AudioFocusRequest(GAIN_TRANSIENT_MAY_DUCK)")
+        if (!answer.await(FOCUS_WAIT_MS, TimeUnit.MILLISECONDS)) {
+            GearslipLog.i("$tag: no focus answer after ${FOCUS_WAIT_MS}ms - speaking anyway")
+        }
+        focusAnswer = null
+    }
+
+    /** Gives back what [askForSpeakers] took, so the other source comes back to full volume. */
+    fun handBackSpeakers() {
+        if (!holdsSpeakers) return
+        holdsSpeakers = false
+        answerDueBy = System.currentTimeMillis() + FOCUS_WAIT_MS
+        runCatching { sendControl(MSG_FOCUS_REQUEST, Protobuf.varintField(1, FOCUS_RELEASE.toLong())) }
+        GearslipLog.i("$tag: -> AudioFocusRequest(RELEASE)")
+    }
+
     fun opened(status: Int) {
         GearslipLog.i("$tag: <- ChannelOpenResponse: status=$status")
         if (status != 0) {
@@ -161,6 +207,12 @@ class AudioLink(
     fun onFocus(state: Int) {
         val name = FOCUS_STATES[state] ?: "unknown($state)"
         GearslipLog.i("$tag: <- AudioFocusResponse state=$name")
+        if (!asksFocus) {
+            // Directions speak whatever the answer: a lost turn is worse than a loud one.
+            answerDueBy = 0L
+            focusAnswer?.countDown()
+            return
+        }
         val had = focusGranted
         focusGranted = state == FOCUS_STATE_GAIN || state == FOCUS_STATE_GAIN_TRANSIENT ||
             state == FOCUS_STATE_GAIN_MEDIA_ONLY
@@ -181,7 +233,19 @@ class AudioLink(
         startStream()
     }
 
+    /**
+     * Guards starting and stopping. [start] starts the stream at once for head units that never
+     * answer the focus request, and the car's answer arrives on another thread and starts it
+     * too: without this both got through, so the car got Start twice and two AAC encoders, and a
+     * 2014 head unit dropped the connection on the first audio.
+     */
+    private val startLock = Any()
+
     private fun startStream() {
+        synchronized(startLock) { startStreamLocked() }
+    }
+
+    private fun startStreamLocked() {
         if (!ready || started) return
         sendOnChannel(
             MSG_START,
@@ -200,6 +264,10 @@ class AudioLink(
     }
 
     override fun stop() {
+        synchronized(startLock) { stopLocked() }
+    }
+
+    private fun stopLocked() {
         if (!started) return
         started = false
         synchronized(ackLock) { ackLock.notifyAll() }
@@ -286,6 +354,7 @@ class AudioLink(
         configTimer?.interrupt()
         configTimer = null
         stop()
+        handBackSpeakers()
         ready = false
         onClose(this)
     }
@@ -303,7 +372,9 @@ class AudioLink(
         private const val MSG_SETUP_ANSWER = 255
         private const val STATUS_READY = 2
         private const val FOCUS_GAIN = 1
+        private const val FOCUS_GAIN_TRANSIENT_MAY_DUCK = 3
         private const val FOCUS_RELEASE = 4
+        private const val FOCUS_WAIT_MS = 500L
         private const val FOCUS_STATE_GAIN = 1
         private const val FOCUS_STATE_GAIN_TRANSIENT = 2
         private const val FOCUS_STATE_GAIN_MEDIA_ONLY = 6

gearslip/src/main/java/app/seb3thehacker/gearslip/audio/CarAudio.kt

@@ -44,6 +44,9 @@ object CarAudio {
 
     @Volatile private var link: Link? = null
 
+    /** Opens the car's media channel, left closed while music went over Bluetooth; null once open. */
+    @Volatile var openSink: (() -> Unit)? = null
+
     /** Rate and channel count the capture should use: the car's, or a sensible default. */
     val sampleRate get() = link?.sampleRate ?: 48_000
     val channels get() = link?.channels ?: 2
@@ -71,6 +74,7 @@ object CarAudio {
         when (_capture.value) {
             Capture.ON, Capture.ASKING, Capture.DENIED -> return
             Capture.OFF -> if (link == null) {
+                openSink?.invoke()
                 GearslipLog.i("audio: waiting for the car to offer an audio sink")
             } else {
                 ask()

gearslip/src/main/java/app/seb3thehacker/gearslip/call/CarCalls.kt

@@ -23,19 +23,19 @@ data class Caller(val number: String, val name: String?) {
 sealed interface CallUiState {
     data object None : CallUiState
     data class Ringing(val caller: Caller, val canDecline: Boolean) : CallUiState
-    data class Active(val caller: Caller?) : CallUiState
+    /** [since] is the uptime the call went off-hook, for the timer. */
+    data class Active(val caller: Caller?, val since: Long) : CallUiState
 }
 
 /**
- * Tracks the phone's call state for the car screen, and answers or declines through the two
+ * Tracks the phone's call state for the car screen, and answers or declines through the
  * doors a sideloaded app can use: [android.telecom.TelecomManager.acceptRingingCall] to answer,
- * and [GearslipCallScreening]'s response to decline one that is still ringing.
+ * [GearslipCallScreening]'s response to decline one that is still ringing, and
+ * [android.telecom.TelecomManager.endCall] to hang up, which needs only ANSWER_PHONE_CALLS for an
+ * ordinary carrier call. Mute is the phone's microphone mute, put back when the call ends.
  *
- * Ending a call already answered needs MODIFY_PHONE_STATE, a privileged permission Gearslip
- * cannot hold, so a call taken here is finished the way it would be without Gearslip at all -
- * from the phone itself, a paired headset, or the car's own Bluetooth if it has any. Call audio
- * stays on the phone's normal voice path too; nothing here sends it over the USB link, which
- * only ever carries media playback.
+ * Call audio stays on the phone's normal voice path; nothing here sends it over the USB link,
+ * which only ever carries media playback.
  */
 object CarCalls {
 
@@ -47,9 +47,14 @@ object CarCalls {
     private var pendingRespond: ((allow: Boolean) -> Unit)? = null
     private var ringingCaller: Caller? = null
 
+    private val _muted = MutableStateFlow(false)
+    val muted: StateFlow<Boolean> = _muted.asStateFlow()
+    private var audio: android.media.AudioManager? = null
+
     fun start(context: Context) {
         if (watcher != null) return
         if (context.checkSelfPermission(Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) return
+        audio = context.getSystemService(android.media.AudioManager::class.java)
         val manager = context.getSystemService(TelephonyManager::class.java) ?: return
         val callback = object : TelephonyCallback(), TelephonyCallback.CallStateListener {
             override fun onCallStateChanged(state: Int) = onPhoneState(state)
@@ -66,6 +71,7 @@ object CarCalls {
         watcher = null
         pendingRespond = null
         ringingCaller = null
+        unmute()
         _state.value = CallUiState.None
     }
 
@@ -74,11 +80,15 @@ object CarCalls {
             TelephonyManager.CALL_STATE_IDLE -> {
                 pendingRespond = null
                 ringingCaller = null
+                // A mute left on would silence the microphone for everything after the call.
+                unmute()
                 _state.value = CallUiState.None
             }
             TelephonyManager.CALL_STATE_OFFHOOK -> {
                 pendingRespond = null
-                _state.value = CallUiState.Active(ringingCaller)
+                if (_state.value !is CallUiState.Active) {
+                    _state.value = CallUiState.Active(ringingCaller, android.os.SystemClock.uptimeMillis())
+                }
             }
             TelephonyManager.CALL_STATE_RINGING -> {
                 // The number itself only ever arrives through the screening service; if this
@@ -109,6 +119,39 @@ object CarCalls {
         runCatching { respond(false) }.onFailure { GearslipLog.w("calls: decline failed: ${it.message}") }
     }
 
+    /** A call Gearslip itself is placing, so the call pill can say who it's to. */
+    fun outgoingCall(context: Context, number: String) {
+        ringingCaller = Caller(number, lookUpName(context, number))
+    }
+
+    fun end(context: Context) {
+        if (context.checkSelfPermission(Manifest.permission.ANSWER_PHONE_CALLS) != PackageManager.PERMISSION_GRANTED) {
+            GearslipLog.w("calls: ending a call needs ANSWER_PHONE_CALLS, which was never granted")
+            return
+        }
+        val telecom = context.getSystemService(TelecomManager::class.java) ?: return
+        @Suppress("DEPRECATION")
+        runCatching { telecom.endCall() }
+            .onSuccess { if (!it) GearslipLog.w("calls: the phone wouldn't end the call") }
+            .onFailure { GearslipLog.w("calls: end failed: ${it.message}") }
+    }
+
+    fun toggleMute() {
+        val manager = audio ?: return
+        val want = !_muted.value
+        runCatching { manager.isMicrophoneMute = want }
+            .onFailure { GearslipLog.w("calls: mute failed: ${it.message}") }
+        // Read back rather than trusted: some phones let the call app overrule it.
+        _muted.value = manager.isMicrophoneMute
+        if (_muted.value != want) GearslipLog.w("calls: the phone didn't take the mute change")
+    }
+
+    private fun unmute() {
+        if (!_muted.value) return
+        runCatching { audio?.isMicrophoneMute = false }
+        _muted.value = false
+    }
+
     fun answer(context: Context) {
         if (context.checkSelfPermission(Manifest.permission.ANSWER_PHONE_CALLS) != PackageManager.PERMISSION_GRANTED) {
             GearslipLog.w("calls: answer needs ANSWER_PHONE_CALLS, which was never granted")

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CallOverlay.kt

@@ -33,21 +33,17 @@ import app.seb3thehacker.gearslip.call.CallUiState
 import app.seb3thehacker.gearslip.call.CarCalls
 
 /**
- * Sits above whatever the car is showing while a call is ringing or under way. Ringing takes the
- * whole screen, because nothing else matters more right now; an active call is a thin band along
- * the top, since from here the driver can only see who it is, not end it - see [CarCalls].
+ * Takes the whole car screen while a call is ringing, because nothing else matters more right
+ * now. A call under way moves into the nav bar instead (see NavCallPill), so it covers nothing.
  */
 @Composable
-fun CallOverlay(modifier: Modifier = Modifier) {
+fun CallOverlay() {
     val state by CarCalls.state.collectAsState()
     val context = LocalContext.current.applicationContext
 
     when (val s = state) {
-        // Covers the box regardless of where the caller aligned it, so the alignment below is
-        // only ever felt by the active-call banner, which is the one that isn't full-screen.
         is CallUiState.Ringing -> IncomingCall(s, onAnswer = { CarCalls.answer(context) }, onDecline = CarCalls::decline)
-        is CallUiState.Active -> ActiveCallBanner(s, modifier)
-        CallUiState.None -> {}
+        else -> {}
     }
 }
 
@@ -110,25 +106,3 @@ private fun CallButton(icon: ImageVector, label: String, color: Color, enabled:
         Text(label, style = MaterialTheme.typography.labelLarge)
     }
 }
-
-@Composable
-private fun ActiveCallBanner(s: CallUiState.Active, modifier: Modifier = Modifier) {
-    Surface(
-        color = MaterialTheme.colorScheme.primaryContainer,
-        contentColor = MaterialTheme.colorScheme.onPrimaryContainer,
-        modifier = modifier.fillMaxWidth(),
-    ) {
-        Row(
-            Modifier.padding(horizontal = 20.dp, vertical = 10.dp),
-            horizontalArrangement = Arrangement.Center,
-        ) {
-            Icon(Icons.Filled.Call, contentDescription = null, modifier = Modifier.size(20.dp))
-            Spacer(Modifier.height(0.dp))
-            Text(
-                "  On a call" + (s.caller?.let { " with ${it.label}" } ?: ""),
-                style = MaterialTheme.typography.labelLarge,
-                fontWeight = FontWeight.SemiBold,
-            )
-        }
-    }
-}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarAppStage.kt

@@ -16,6 +16,7 @@ import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.height
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
@@ -34,8 +35,11 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.layout.boundsInWindow
+import androidx.compose.ui.layout.onGloballyPositioned
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
+import androidx.compose.material.icons.filled.Close
 import androidx.compose.ui.viewinterop.AndroidView
 import app.seb3thehacker.gearslip.GearslipLog
 import app.seb3thehacker.gearslip.host.CarAppConnection
@@ -59,13 +63,22 @@ fun CarAppStage(
 ) {
     val template by connection.template.collectAsStateWithLifecycle()
 
+    val cover = remember { ChromeCover() }
+    val navBar = LocalNavBarInset.current
+
     Box(Modifier.fillMaxSize()) {
         // The app's own drawing goes underneath; everything else is the host's rendering of
         // the template it described, laid over the top.
-        if (status.surfaceRequested) {
-            AppSurface(connection, frame, template, Modifier.fillMaxSize())
+        androidx.compose.runtime.CompositionLocalProvider(LocalChromeCover provides cover, LocalCarAppConnection provides connection) {
+            if (status.surfaceRequested) {
+                AppSurface(connection, frame, template, Modifier.fillMaxSize())
+            }
+            TemplateChrome(
+                template,
+                Modifier.fillMaxSize().padding(top = if (embedded) 0.dp else CHROME_BAR, bottom = navBar),
+            )
+            BottomCover(navBar, Modifier.align(Alignment.BottomCenter))
         }
-        TemplateChrome(template, Modifier.fillMaxSize().padding(top = if (embedded) 0.dp else CHROME_BAR))
         if (!embedded) ChromeBar(status, onDisconnect, Modifier.align(Alignment.TopCenter))
     }
 }
@@ -84,14 +97,25 @@ private fun AppSurface(
     modifier: Modifier = Modifier,
 ) {
     var size by remember { mutableStateOf(0 to 0) }
+    var bounds by remember { mutableStateOf<androidx.compose.ui.geometry.Rect?>(null) }
+    val cover = LocalChromeCover.current
 
-    // The app lays its map out around whatever the host covers, so a template change moves the
-    // visible area even though the surface itself hasn't changed.
-    LaunchedEffect(template, size) {
-        val (width, height) = size
+    // The app lays its map out around whatever the host covers, so a template change or a card
+    // changing size moves the visible area even though the surface itself hasn't changed.
+    val (width, height) = size
+    val measured = bounds?.takeIf { width > 0 && height > 0 }?.let { cover?.visibleWithin(it, width, height) }
+    // The card column moves the map's centre but isn't taken out of the stable area: apps size
+    // their own overlays from it, and Vela's speedometer shrank to fit the strip right of the cards.
+    val measuredStable = bounds?.takeIf { width > 0 && height > 0 }?.let { cover?.visibleWithin(it, width, height, skip = CoverEdge.START) }
+    LaunchedEffect(template, size, measured, measuredStable) {
         if (width > 0 && height > 0) {
-            val visible = visibleAreaFor(template, width, height)
-            connection.reportAreas(visible = visible, stable = visible)
+            val visible = visibleAreaFor(template, width, height, measured)
+            val stable = if (!isContentTemplate(template)) {
+                visibleAreaFor(template, width, height, measuredStable)
+            } else {
+                visible
+            }
+            connection.reportAreas(visible = visible, stable = stable)
         }
     }
 
@@ -101,7 +125,9 @@ private fun AppSurface(
     // new one on it before releasing the old: the old display's disconnect then takes the new one's
     // connection with it and the map freezes for good. The nav bar hiding for the search keyboard
     // and the lyrics pane opening both resize this area.
-    androidx.compose.foundation.layout.BoxWithConstraints(modifier) {
+    androidx.compose.foundation.layout.BoxWithConstraints(
+        modifier.onGloballyPositioned { bounds = it.boundsInWindow() },
+    ) {
         val epoch by connection.surfaceEpoch.collectAsState()
         androidx.compose.runtime.key(constraints.maxWidth, constraints.maxHeight, epoch) {
             SurfaceHost(connection, frame, onSize = { size = it }, Modifier.fillMaxSize())
@@ -189,28 +215,31 @@ private fun ChromeBar(
     onDisconnect: () -> Unit,
     modifier: Modifier = Modifier,
 ) {
+    // The app's name and a way out, nothing else: which template is showing, or whether the
+    // app has drawn yet, is for the log, not the driver.
     Surface(
-        color = Color.Black.copy(alpha = 0.55f),
-        contentColor = Color.White,
-        modifier = modifier.fillMaxWidth(),
+        color = MaterialTheme.colorScheme.surfaceContainer,
+        contentColor = MaterialTheme.colorScheme.onSurface,
+        modifier = modifier.fillMaxWidth().height(CHROME_BAR),
     ) {
         Row(
-            Modifier.padding(horizontal = 16.dp, vertical = 6.dp),
+            Modifier.padding(horizontal = 16.dp),
             verticalAlignment = Alignment.CenterVertically,
         ) {
-            Column(Modifier.weight(1f)) {
-                Text(
-                    status.app ?: "Car app",
-                    style = MaterialTheme.typography.titleSmall,
-                    fontWeight = FontWeight.SemiBold,
-                )
-                val detail = buildList {
-                    status.template?.let { add(it) }
-                    add(if (status.surfaceAttached) "drawing" else "waiting for the app")
-                }.joinToString(" - ")
-                Text(detail, style = MaterialTheme.typography.bodySmall)
-            }
-            GsButton(onClick = onDisconnect, tone = GsTone.Tonal) { Text("Stop") }
+            Text(
+                status.app ?: "Car app",
+                style = MaterialTheme.typography.titleSmall,
+                fontWeight = FontWeight.SemiBold,
+                modifier = Modifier.weight(1f),
+            )
+            GsIconButton(
+                androidx.compose.material.icons.Icons.Filled.Close,
+                "Close ${status.app ?: "the app"}",
+                onDisconnect,
+                size = 36.dp,
+                iconSize = 20.dp,
+                shape = androidx.compose.foundation.shape.CircleShape,
+            )
         }
     }
 }
@@ -220,3 +249,6 @@ private val CHROME_BAR = 44.dp
 
 /** Slower than this when the finger lifts and it was a drag that stopped, not a fling. */
 private const val FLING_MIN_PX_S = 400f
+
+/** The app connection a template on screen belongs to: the map app's, or the one opened from the launcher. */
+internal val LocalCarAppConnection = androidx.compose.runtime.staticCompositionLocalOf { CarServices.nav }

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarFullscreen.kt

@@ -0,0 +1,51 @@
+package app.seb3thehacker.gearslip.car
+
+import android.os.SystemClock
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
+
+/**
+ * Full screen for the screen that asks for it (the browser, or a video in it): no header and no
+ * nav bar. A swipe in from the top or bottom edge brings the nav bar back for a few seconds,
+ * with a button to leave full screen; [revealed] says when.
+ */
+object CarFullscreen {
+
+    var active by mutableStateOf(false)
+        private set
+
+    var revealed by mutableStateOf(false)
+        private set
+
+    private var lastTouch = 0L
+
+    fun enter() {
+        active = true
+        revealed = false
+    }
+
+    fun exit() {
+        active = false
+        revealed = false
+    }
+
+    /** A swipe in from an edge: show the nav bar and the way out. */
+    fun reveal() {
+        if (!active) return
+        lastTouch = SystemClock.uptimeMillis()
+        revealed = true
+    }
+
+    /** Any touch keeps a revealed bar up, so it doesn't slide away under a finger reaching for it. */
+    fun touch() {
+        if (revealed) lastTouch = SystemClock.uptimeMillis()
+    }
+
+    /** Called on a timer; hides the bar again after [REVEAL_MS] without a touch. */
+    fun tick() {
+        if (revealed && SystemClock.uptimeMillis() - lastTouch >= REVEAL_MS) revealed = false
+    }
+
+    private const val REVEAL_MS = 4_000L
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarHomeScreen.kt

@@ -93,13 +93,14 @@ fun CarHome() {
         if (onHome) seenHome[0] = true
     }
     val splitScreen = phase == CarMedia.Phase.READY && now.isActive && panel != SidePanel.NONE
+    val playerLeft by CarSettings.playerLeft.collectAsStateWithLifecycle()
 
-    // No outer padding on any side, split screen or not - only the gap between the two panes
-    // when the player is sharing the screen with the map.
-    Row(
-        Modifier.fillMaxSize(),
-        horizontalArrangement = Arrangement.spacedBy(8.dp),
-    ) {
+    // No padding anywhere, split screen or not: the player sits flush against the map.
+    Row(Modifier.fillMaxSize()) {
+        val side = Modifier.weight(1f).fillMaxHeight().padding(bottom = LocalNavBarInset.current)
+        if (splitScreen && playerLeft) {
+            if (panel == SidePanel.LYRICS) SideLyrics(now, side) else DockedPlayer(now, side)
+        }
         Box(
             Modifier
                 .weight(if (splitScreen) 2.1f else 1f)
@@ -107,8 +108,7 @@ fun CarHome() {
         ) {
             MapPane(navStatus, frame)
         }
-        if (splitScreen) {
-            val side = Modifier.weight(1f).fillMaxHeight()
+        if (splitScreen && !playerLeft) {
             if (panel == SidePanel.LYRICS) SideLyrics(now, side) else DockedPlayer(now, side)
         }
     }

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarKeyboard.kt

@@ -44,6 +44,12 @@ object CarKeyboardVisibility {
     val state = mutableStateOf(false)
 }
 
+/**
+ * True for the car UI the phone's own car preview draws. The phone is in hand there, so a
+ * [CarKeyboard] draws nothing and the phone's keyboard does the typing instead (see [PhoneTyping]).
+ */
+val LocalCarPreview = compositionLocalOf { false }
+
 /**
  * A keyboard the host draws itself.
  *
@@ -73,10 +79,11 @@ fun CarKeyboard(
 ) {
     var symbols by remember { mutableStateOf(false) }
     var shifted by remember { mutableStateOf(false) }
+    val preview = LocalCarPreview.current
 
-    DisposableEffect(Unit) {
-        CarKeyboardVisibility.state.value = true
-        onDispose { CarKeyboardVisibility.state.value = false }
+    DisposableEffect(preview) {
+        if (!preview) CarKeyboardVisibility.state.value = true
+        onDispose { if (!preview) CarKeyboardVisibility.state.value = false }
     }
 
     // The same field on the phone, for typing on its own keyboard: see [PhoneTyping].
@@ -88,6 +95,7 @@ fun CarKeyboard(
     }
     DisposableEffect(phoneField) { onDispose { PhoneTyping.close(phoneField) } }
     LaunchedEffect(text) { PhoneTyping.carText(phoneField, text) }
+    if (preview) return
 
     val rows = if (symbols) SYMBOL_ROWS else LETTER_ROWS
     val keyHeight = keyHeight(LocalConfiguration.current.screenHeightDp)

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarLauncher.kt

@@ -119,35 +119,61 @@ internal object LauncherCache {
             context.packageManager.getApplicationIcon(pkg).toBitmap(128, 128).asImageBitmap()
         }.getOrNull()
 
-        val navApps = CarAppCatalog.installed(context)
-        val mediaApps = MediaCatalog.installed(context)
-        // Some apps (Spotify among them) ship both a Car App Library template and a legacy
-        // MediaBrowserService, which otherwise land as two identically-labeled tiles with no
-        // way to tell them apart. They're genuinely different screens - browsing versus Now
-        // Playing - so only the label needs disambiguating, not the tile itself.
-        val mediaPackages = mediaApps.map { it.component.packageName }.toSet()
+        val carApps = CarAppCatalog.installed(context).associateBy { it.component.packageName }
+        val mediaApps = MediaCatalog.installed(context).associateBy { it.component.packageName }
+        val messagingApps = MessagingCatalog.installed(context).associateBy { it.packageName }
 
-        val messagingApps = MessagingCatalog.installed(context)
-        // Google Messages ships its own car app, which won't start under Gearslip. Gearslip's
-        // own Messages screen does the same job, so a messenger gets only that tile.
-        val messagingPackages = messagingApps.map { it.packageName }.toSet()
-
-        val nav = navApps
-            .filter { it.component.packageName !in messagingPackages }
-            // An app whose template screen is rejected but whose player works through Gearslip
-            // (Spotify) shows only its player tile - a "· Browse" tile beside it would just report
-            // that the car screen isn't supported.
-            .filter { !(KnownApps.screenBroken(it.component.packageName) && KnownApps.playerWorks(it.component.packageName)) }
-            .map {
-                val label = if (it.component.packageName in mediaPackages) "${it.label} · Browse" else it.label
-                Entry(label, iconOf(it.component.packageName), template = it)
+        // One decision per app over everything it offers a car - a car screen, a player, car
+        // notifications - rather than a filter per kind that has to know about the others.
+        val tiles = (carApps.keys + mediaApps.keys + messagingApps.keys).flatMap { pkg ->
+            val icon by lazy { iconOf(pkg) }
+            tilesFor(carApps[pkg], mediaApps[pkg], messagingApps[pkg]).map { tile ->
+                when (tile) {
+                    is AppTile.Screen -> Entry(tile.label, icon, template = tile.app)
+                    is AppTile.Player -> Entry(tile.app.label, icon, media = tile.app)
+                    is AppTile.Messages -> Entry(tile.app.label, icon, messaging = tile.app)
+                }
             }
-        val media = mediaApps.map { Entry(it.label, iconOf(it.component.packageName), media = it) }
-        // A messenger that is also a car media app keeps only its player tile.
-        val messaging = messagingApps
-            .filter { it.packageName !in mediaPackages }
-            .map { Entry(it.label, iconOf(it.packageName), messaging = it) }
-        return (nav + media + messaging).sortedBy { it.label.lowercase() }.also { flow.value = it }
+        }
+        return tiles.sortedBy { it.label.lowercase() }.also { flow.value = it }
+    }
+}
+
+/** What one app gets on the launcher. */
+private sealed interface AppTile {
+    class Screen(val app: TemplateApp, val label: String) : AppTile
+    class Player(val app: app.seb3thehacker.gearslip.media.MediaApp) : AppTile
+    class Messages(val app: app.seb3thehacker.gearslip.notify.MessagingApp) : AppTile
+}
+
+/**
+ * The tiles for one app, from what it offers.
+ *
+ * - A car screen that is something other than media or messaging (RF Sentinel's POI screen) is
+ *   the app: its media service only makes sound, and its notifications are alerts, so it gets the
+ *   one tile under its own name.
+ * - A media app with both a car screen and a player (Spotify) gets both, the screen labelled
+ *   "· Browse", since they really are different screens - unless the screen is known to refuse
+ *   Gearslip while the player works, when the Browse tile would only report that.
+ * - A messenger's own car screen (Google Messages) won't start under Gearslip, and Gearslip's
+ *   Messages screen does the job, so it gets only that - and a messenger that is also a media
+ *   app keeps only its player.
+ */
+private fun tilesFor(
+    car: TemplateApp?,
+    media: app.seb3thehacker.gearslip.media.MediaApp?,
+    messaging: app.seb3thehacker.gearslip.notify.MessagingApp?,
+): List<AppTile> {
+    if (car != null && !car.isMediaScreen && car.kind != "messaging") return listOf(AppTile.Screen(car, car.label))
+    val pkg = car?.component?.packageName ?: media?.component?.packageName ?: messaging?.packageName ?: return emptyList()
+    return buildList {
+        val screenRefused = KnownApps.screenBroken(pkg) && KnownApps.playerWorks(pkg)
+        val messengerScreen = messaging != null && (car?.kind == "messaging" || car?.kind == "app")
+        if (car != null && !messengerScreen && !(media != null && screenRefused)) {
+            add(AppTile.Screen(car, if (media != null) "${car.label} · Browse" else car.label))
+        }
+        if (media != null) add(AppTile.Player(media))
+        else if (messaging != null) add(AppTile.Messages(messaging))
     }
 }
 

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarNavBar.kt

@@ -0,0 +1,664 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.compose.material.icons.filled.Call
+import app.seb3thehacker.gearslip.call.CarCalls
+import app.seb3thehacker.gearslip.call.CallUiState
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.LocalIndication
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.BoxWithConstraints
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.offset
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.background
+import androidx.compose.foundation.gestures.detectTapGestures
+import androidx.compose.ui.graphics.lerp
+import androidx.compose.ui.graphics.Brush
+import androidx.compose.foundation.layout.widthIn
+import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.border
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.foundation.layout.BoxScope
+import androidx.car.app.model.CarIcon
+import androidx.car.app.navigation.model.NavigationTemplate
+import androidx.car.app.navigation.model.RoutingInfo
+import app.seb3thehacker.gearslip.host.CarAppConnection
+import app.seb3thehacker.gearslip.host.display
+import app.seb3thehacker.gearslip.host.text
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material.icons.filled.PlayArrow
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.dynamicDarkColorScheme
+import androidx.compose.material3.dynamicLightColorScheme
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.ui.hapticfeedback.HapticFeedback
+import androidx.compose.ui.hapticfeedback.HapticFeedbackType
+import androidx.compose.ui.platform.LocalHapticFeedback
+import androidx.compose.ui.platform.LocalView
+import androidx.compose.runtime.State
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.produceState
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
+import androidx.compose.animation.animateContentSize
+import android.media.session.PlaybackState
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.input.pointer.PointerEventPass
+import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.asImageBitmap
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.res.vectorResource
+import androidx.compose.ui.text.style.TextOverflow
+import app.seb3thehacker.gearslip.R
+import app.seb3thehacker.gearslip.car.theme.GsColors
+import app.seb3thehacker.gearslip.car.theme.withTintedSurfaces
+import app.seb3thehacker.gearslip.car.theme.GsIconBox
+import app.seb3thehacker.gearslip.car.theme.GsIconButton
+import app.seb3thehacker.gearslip.car.theme.GsButton
+import app.seb3thehacker.gearslip.car.theme.GsTone
+import app.seb3thehacker.gearslip.car.theme.gsColors
+import app.seb3thehacker.gearslip.car.theme.GsThemes
+import app.seb3thehacker.gearslip.car.theme.LocalGsTheme
+import app.seb3thehacker.gearslip.media.CarMedia
+import app.seb3thehacker.gearslip.media.MediaArt
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.platform.LocalDensity
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.Density
+import androidx.compose.ui.unit.dp
+import app.seb3thehacker.gearslip.notify.CarNotifications
+import androidx.core.graphics.drawable.toBitmap
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.withContext
+import java.text.DateFormat
+import java.util.Date
+
+// The nav bar along the bottom of the car screen: home, apps, the assistant, running apps,
+// the next turn or a call, the player, and the clock. Split out of CarUi.kt.
+
+/**
+ * "Home > Apps > Settings", like a file manager's address bar: hidden at Home itself (nothing to
+ * show yet), and grows by one crumb for every screen pushed from there. The back arrow undoes one
+ * step; a crumb jumps straight to it, dropping everything after - this is the only on-screen way
+ * back at all, since a car touchscreen has no hardware button for it.
+ */
+@Composable
+private fun BreadcrumbBar(navigator: CarNavigator) {
+    val trail = navigator.trail
+    if (trail.size <= 1) return
+    Row(
+        Modifier.fillMaxWidth().height(40.dp).padding(start = 2.dp, end = 10.dp),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        GsIconButton(Icons.AutoMirrored.Filled.ArrowBack, "Back", navigator::back, size = 32.dp, iconSize = 20.dp)
+        Spacer(Modifier.width(2.dp))
+        trail.forEachIndexed { index, crumb ->
+            val isLast = index == trail.lastIndex
+            Text(
+                crumb.label,
+                style = MaterialTheme.typography.labelLarge,
+                fontWeight = if (isLast) FontWeight.SemiBold else FontWeight.Normal,
+                color = if (isLast) MaterialTheme.colorScheme.onSurface else MaterialTheme.colorScheme.onSurfaceVariant,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis,
+                modifier = if (isLast) Modifier else Modifier
+                    .clip(RoundedCornerShape(6.dp))
+                    .clickable { navigator.jumpTo(index) }
+                    .padding(horizontal = 4.dp, vertical = 2.dp),
+            )
+            if (!isLast) {
+                Text(
+                    "›",
+                    style = MaterialTheme.typography.labelLarge,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    modifier = Modifier.padding(horizontal = 2.dp),
+                )
+            }
+        }
+    }
+}
+
+/**
+ * Apps and open/pinned shortcuts on the left; now-playing pill against them; clock (tap for
+ * calendar and weather), phone battery and the darkness signal on the right. Icon-only: a driver
+ * reads a glyph faster than a label, and it keeps the bar short enough to leave the app underneath
+ * more room.
+ */
+@Composable
+internal fun CarNavBar(navigator: CarNavigator) {
+    val battery by CarEnvironment.battery.collectAsState()
+    val now by rememberNow()
+    val weather by Weather.state.collectAsState()
+    val weatherData = (weather as? WeatherState.Ready)?.data
+
+    val pinnedIds by CarSettings.pinnedApps.collectAsState()
+    val entries = rememberAllEntries()
+    val pinnedEntries = remember(entries, pinnedIds) {
+        pinnedIds.mapNotNull { id -> entries.find { it.componentId == id } }
+    }
+    val frame by CarEnvironment.frame.collectAsState()
+    val running = rememberRunningApps()
+
+    Surface(color = MaterialTheme.colorScheme.surfaceContainer) {
+        BoxWithConstraints(Modifier.fillMaxWidth().height(NAV_BAR_HEIGHT).padding(horizontal = 10.dp)) {
+            Row(Modifier.fillMaxSize(), verticalAlignment = Alignment.CenterVertically) {
+                // Home and Apps are two different places now, not a toggle on one button - the
+                // breadcrumb trail is how you retrace your steps, but reaching for either of
+                // these two from three screens deep in a media app shouldn't mean reading it
+                // first.
+                NavHomeButton(navigator, entries, running)
+                Spacer(Modifier.width(6.dp))
+                NavItem(MediaIcons.Apps, navigator.current == CarScreen.Apps) { navigator.apps() }
+                Spacer(Modifier.width(6.dp))
+                NavAssistantIcon()
+
+                // Pinned shortcuts, then whatever else is open right now. A pinned app that's also
+                // open stays in its pinned spot, marked with a dot, instead of showing up twice.
+                // The map app lives on the Home button, so it never gets a second icon here.
+                val runningEntries = running.keys
+                    .filter { it !in pinnedIds && running[it] != RunningSlot.NAV }
+                    .mapNotNull { id -> entries.find { it.componentId == id } }
+                val shownPins = pinnedEntries.filter { running[it.componentId] != RunningSlot.NAV }
+                if (shownPins.isNotEmpty() || runningEntries.isNotEmpty()) NavDivider()
+                shownPins.forEach { entry -> NavEntryIcon(entry, running, navigator, frame) }
+                if (shownPins.isNotEmpty() && runningEntries.isNotEmpty()) NavDivider()
+                runningEntries.forEach { entry -> NavEntryIcon(entry, running, navigator, frame) }
+
+                // Next turn first, off the map only; the player shares the space when it fits,
+                // and gives way to the turn when it doesn't.
+                // A call takes the player's place until it ends.
+                val turn = rememberNextTurn().takeIf { navigator.current != CarScreen.Home }
+                val call = CarCalls.state.collectAsState().value as? CallUiState.Active
+                BoxWithConstraints(Modifier.weight(1f).padding(horizontal = 16.dp), contentAlignment = Alignment.Center) {
+                    val roomForBoth = maxWidth >= TURN_AND_PLAYER_MIN_WIDTH
+                    Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(10.dp)) {
+                        if (call == null || roomForBoth) turn?.let { NavTurnPill(it) { navigator.home() } }
+                        if (call != null) {
+                            NavCallPill(call, Modifier.weight(1f, fill = false))
+                        } else if (turn == null || roomForBoth) {
+                            NavNowPlaying(navigator, selected = navigator.current == CarScreen.Media, modifier = Modifier.weight(1f, fill = false))
+                        }
+                    }
+                }
+
+                // Weather no longer has its own chip - the temperature alone (no icon, no room
+                // for one) sits where "Night"/"Day" used to, freeing a whole chip's width for the
+                // Home button above.
+                // The clock is also the notifications button: the dashboard lists them under the
+                // calendar and weather, and a dot here marks anything unread.
+                val unread by CarNotifications.unread.collectAsState()
+                NavChip(
+                    navigator.current == CarScreen.Dashboard || navigator.current is CarScreen.Notifications,
+                    { navigator.dashboard() },
+                ) {
+                    if (unread > 0) {
+                        Box(
+                            Modifier
+                                .align(Alignment.TopEnd)
+                                .offset(x = 8.dp, y = (-2).dp)
+                                .size(8.dp)
+                                .clip(CircleShape)
+                                .background(MaterialTheme.colorScheme.primary),
+                        )
+                    }
+                    Column(horizontalAlignment = Alignment.End) {
+                        Text(
+                            DateFormat.getTimeInstance(DateFormat.SHORT).format(Date(now)),
+                            style = MaterialTheme.typography.titleMedium,
+                            fontWeight = FontWeight.SemiBold,
+                        )
+                        Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(3.dp)) {
+                            if (battery.percent >= 0) {
+                                Text(
+                                    "${battery.percent}%",
+                                    style = MaterialTheme.typography.labelMedium,
+                                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                                )
+                                if (battery.charging) {
+                                    ChargingGlyph(Modifier.size(13.dp))
+                                }
+                            }
+                            weatherData?.let { w ->
+                                Text(
+                                    "  ·  ${w.temp}°",
+                                    style = MaterialTheme.typography.labelMedium,
+                                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                                )
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+/**
+ * Home: the map, with the player or lyrics beside it. While a map app runs, the button wears that
+ * app's icon and a long press offers to close it, so the app needs no icon of its own on the bar.
+ */
+@Composable
+private fun NavHomeButton(navigator: CarNavigator, entries: List<Entry>, running: Map<String, RunningSlot>) {
+    val selected = navigator.current == CarScreen.Home
+    val navId = running.entries.firstOrNull { it.value == RunningSlot.NAV }?.key
+    val navEntry = navId?.let { id -> entries.find { it.componentId == id } }
+    GsIconBox(
+        { navigator.home() },
+        colors = navColors(selected),
+        latched = selected,
+        onLongClick = navId?.let { id -> { navigator.showAppMenu(id) } },
+    ) {
+        val icon = navEntry?.icon
+        if (icon != null) {
+            Box(Modifier.padding(NAV_ITEM_PADDING).size(28.dp), contentAlignment = Alignment.Center) {
+                Image(icon, navEntry.label, Modifier.size(28.dp).clip(RoundedCornerShape(7.dp)))
+            }
+        } else {
+            Icon(
+                ImageVector.vectorResource(R.drawable.navigation_24), contentDescription = "Home",
+                modifier = Modifier.padding(NAV_ITEM_PADDING).size(28.dp),
+            )
+        }
+    }
+}
+
+/** Splits the nav bar's sections: Home and Apps, pinned apps, open apps. */
+@Composable
+private fun NavDivider() {
+    Box(
+        Modifier
+            .padding(horizontal = 10.dp)
+            .width(1.dp)
+            .height(28.dp)
+            .background(MaterialTheme.colorScheme.outlineVariant),
+    )
+}
+
+/**
+ * A pinned or open app on the nav bar. Tapping brings it back without reconnecting if it's
+ * already open; a long press opens its menu (pin, unpin, close).
+ */
+@Composable
+private fun NavEntryIcon(
+    entry: Entry,
+    running: Map<String, RunningSlot>,
+    navigator: CarNavigator,
+    frame: CarEnvironment.Frame,
+) {
+    val id = entry.componentId ?: return
+    val slot = running[id]
+    Box(Modifier.padding(horizontal = 3.dp)) {
+        NavAppIcon(
+            entry,
+            open = slot != null,
+            showing = slot != null && slot.isShowing(navigator.current),
+            onLongClick = { navigator.showAppMenu(id) },
+        ) { openApp(entry, slot, navigator, frame) }
+    }
+}
+
+/** One open or pinned app's icon on the nav bar - the same fixed size and shape either way. */
+@Composable
+private fun NavAppIcon(
+    entry: Entry,
+    open: Boolean,
+    showing: Boolean,
+    onLongClick: () -> Unit,
+    onClick: () -> Unit,
+) {
+    val scheme = MaterialTheme.colorScheme
+    GsIconBox(
+        onClick,
+        Modifier.size(44.dp),
+        colors = if (showing) GsColors(scheme.secondaryContainer, scheme.onSecondaryContainer)
+        else GsColors(scheme.surfaceVariant, scheme.onSurfaceVariant),
+        latched = showing,
+        onLongClick = onLongClick,
+    ) {
+        entry.icon?.let { Image(it, entry.label, Modifier.size(30.dp).clip(RoundedCornerShape(8.dp))) }
+        entry.builtIn?.let { Icon(it.glyph, entry.label, Modifier.size(26.dp)) }
+        // Only running apps get the line along the bottom edge, the usual taskbar mark for it.
+        if (open) {
+            Box(
+                Modifier
+                    .align(Alignment.BottomCenter)
+                    .padding(bottom = 2.dp)
+                    .size(width = 12.dp, height = 3.dp)
+                    .clip(RoundedCornerShape(50))
+                    .background(scheme.primary),
+            )
+        }
+    }
+}
+
+/** A tappable group in the bar that stays highlighted while its screen is open, like [NavItem]. */
+@Composable
+private fun NavChip(selected: Boolean, onClick: () -> Unit, content: @Composable BoxScope.() -> Unit) {
+    GsIconBox(onClick, colors = navColors(selected), latched = selected) {
+        Box(Modifier.padding(horizontal = 10.dp, vertical = 2.dp)) { content() }
+    }
+}
+
+/** Every nav bar item is raised, so it reads as pressable; the current screen's takes the accent colour. */
+@Composable
+private fun navColors(selected: Boolean): GsColors {
+    val s = MaterialTheme.colorScheme
+    return if (selected) GsColors(s.secondaryContainer, s.onSecondaryContainer)
+    else GsColors(s.surfaceContainerHighest, s.onSurface)
+}
+
+/**
+ * Between Apps and whatever's actually open, not with the clock/battery group on the right - a
+ * driver reaches for it right after deciding "not a tap for this", same gesture family as the
+ * two buttons beside it.
+ */
+@Composable
+private fun NavAssistantIcon() {
+    val state by CarAssistant.state.collectAsState()
+    val active = state.phase != CarAssistant.Phase.IDLE
+    GsIconBox({ CarAssistant.start() }, colors = navColors(active), latched = active) {
+        MicGlyph(Modifier.padding(NAV_ITEM_PADDING).size(28.dp))
+    }
+}
+
+/** Inner padding of every icon on the nav bar, leaving each button room inside the 56dp bar. */
+private val NAV_ITEM_PADDING = 8.dp
+
+@Composable
+private fun NavItem(icon: ImageVector, selected: Boolean, onClick: () -> Unit) {
+    GsIconBox(onClick, colors = navColors(selected), latched = selected) {
+        Icon(icon, contentDescription = null, modifier = Modifier.padding(NAV_ITEM_PADDING).size(28.dp))
+    }
+}
+
+/** Wall-clock time, ticking on the minute: no reason to redraw (and re-encode) more often. */
+@Composable
+internal fun rememberNow(): State<Long> = produceState(System.currentTimeMillis()) {
+    while (true) {
+        value = System.currentTimeMillis()
+        delay(60_000 - value % 60_000)
+    }
+}
+
+/** How long the pill shows a new song's title before settling to just the controls. */
+private const val TITLE_SHOWN_MS = 3_000L
+
+/** Below this, the nav bar's middle only has room for the turn, not the player beside it. */
+private val TURN_AND_PLAYER_MIN_WIDTH = 520.dp
+
+/** The next manoeuvre, as the running nav app last described it. */
+private class NextTurn(val icon: CarIcon?, val distance: String, val road: String)
+
+/**
+ * Read straight off the nav app's own template: a navigation app keeps sending its routing card
+ * while it's running, whether or not the map is the screen being shown.
+ */
+@Composable
+private fun rememberNextTurn(): NextTurn? {
+    val status by CarServices.nav.status.collectAsState()
+    val template by CarServices.nav.template.collectAsState()
+    // Read so a change of units redraws the distance straight away, not at the next update.
+    CarSettings.units.collectAsState().value
+    if (status.phase != CarAppConnection.Phase.RUNNING) return null
+    val routing = (template as? NavigationTemplate)?.navigationInfo as? RoutingInfo ?: return null
+    if (routing.isLoading) return null
+    val step = routing.currentStep ?: return null
+    return NextTurn(
+        icon = step.maneuver?.icon,
+        distance = routing.currentDistance.display(),
+        road = step.road.text().ifEmpty { step.cue.text() },
+    )
+}
+
+/** The next turn in the nav bar: arrow, how far, onto what. Tapping goes back to the map. */
+@Composable
+private fun NavTurnPill(turn: NextTurn, onClick: () -> Unit) {
+    // Same finish as every other button on the bar, in the accent colour; the text runs a step
+    // bigger than anything else there, since it's the one thing worth a glance mid-drive.
+    GsIconBox(
+        onClick,
+        Modifier.widthIn(max = 340.dp).height(44.dp),
+        colors = gsColors(GsTone.Primary),
+    ) {
+        Row(
+            Modifier.padding(NAV_ITEM_PADDING),
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.spacedBy(8.dp),
+        ) {
+            CarGlyph(turn.icon, Modifier.size(28.dp))
+            if (turn.distance.isNotEmpty()) {
+                Text(turn.distance, style = MaterialTheme.typography.titleLarge, fontWeight = FontWeight.Bold, maxLines = 1)
+            }
+            if (turn.road.isNotEmpty()) {
+                Text(
+                    turn.road,
+                    style = MaterialTheme.typography.titleMedium,
+                    fontWeight = FontWeight.SemiBold,
+                    maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
+                )
+            }
+        }
+    }
+}
+
+/** The call under way: who, how long, and Mute and End right here. Ringing has its own screen. */
+@Composable
+private fun NavCallPill(call: CallUiState.Active, modifier: Modifier = Modifier) {
+    val context = LocalContext.current.applicationContext
+    val muted by CarCalls.muted.collectAsState()
+    val elapsed by produceState(0L, call.since) {
+        while (true) {
+            value = (android.os.SystemClock.uptimeMillis() - call.since) / 1000
+            delay(1000 - (android.os.SystemClock.uptimeMillis() - call.since) % 1000)
+        }
+    }
+    val scheme = MaterialTheme.colorScheme
+    Surface(
+        modifier = modifier.height(44.dp),
+        shape = RoundedCornerShape(14.dp),
+        color = scheme.secondaryContainer,
+        contentColor = scheme.onSecondaryContainer,
+    ) {
+        Row(
+            Modifier.fillMaxHeight().padding(start = 12.dp, end = 4.dp),
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.spacedBy(6.dp),
+        ) {
+            Icon(Icons.Filled.Call, contentDescription = null, modifier = Modifier.size(20.dp))
+            Text(
+                call.caller?.label ?: "On a call",
+                style = MaterialTheme.typography.titleSmall,
+                fontWeight = FontWeight.SemiBold,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis,
+                modifier = Modifier.weight(1f, fill = false),
+            )
+            Text(
+                "%d:%02d".format(elapsed / 60, elapsed % 60),
+                style = MaterialTheme.typography.titleSmall,
+                maxLines = 1,
+            )
+            Spacer(Modifier.width(2.dp))
+            GsIconButton(
+                if (muted) MediaIcons.MicOff else MediaIcons.Mic,
+                if (muted) "Unmute" else "Mute",
+                CarCalls::toggleMute,
+                tone = if (muted) GsTone.Primary else GsTone.Neutral, size = 36.dp, iconSize = 22.dp,
+            )
+            GsIconButton(
+                MediaIcons.CallEnd, "End call", { CarCalls.end(context) },
+                colors = GsColors(scheme.error, scheme.onError), size = 36.dp, iconSize = 22.dp,
+            )
+        }
+    }
+}
+
+/** "Title - Artist" on one line. The text itself cuts it off, and only where the pill runs out of room. */
+private fun nowPlayingLabel(title: String, artist: String): String =
+    listOf(title.trim(), artist.trim()).filter { it.isNotEmpty() }.joinToString(" - ")
+        .ifEmpty { "Nothing playing" }
+
+/**
+ * The player in the nav bar, on every screen. Art and title open the full media screen;
+ * play/pause and skip work right here. The dock button moves the player into the column beside
+ * the map on Home (see [CarHome]), and the pill steps aside there while it's docked - unless the
+ * column is showing lyrics instead, when the pill stays and its dock button swaps them back.
+ */
+@Composable
+private fun NavNowPlaying(navigator: CarNavigator, selected: Boolean, modifier: Modifier = Modifier) {
+    val media = CarServices.media
+    val phase by media.phase.collectAsState()
+    val now by media.now.collectAsState()
+    if (phase != CarMedia.Phase.READY || !now.isActive) return
+    // Docked beside the map, the player is already on screen - the pill steps aside for it.
+    if (navigator.sidePanel == SidePanel.CONTROLS && navigator.current == CarScreen.Home) return
+    // The media screen is the full player already; the pill would only repeat its controls.
+    if (navigator.current == CarScreen.Media) return
+    val context = LocalContext.current
+    val art by produceState(now.art, now.art, now.artUri) { value = now.art ?: MediaArt.load(context, now.artUri) }
+    val position by produceState(now.currentPosition(), now) {
+        while (true) {
+            value = now.currentPosition()
+            if (!now.playing) break
+            delay(1000)
+        }
+    }
+
+    // A new song announces itself: title, play/pause and dock for a few seconds, then the title
+    // goes and the pill settles to just the controls - unless the driver keeps the title up.
+    val keepTitle by CarSettings.playerTitle.collectAsState()
+    var announcing by remember { mutableStateOf(true) }
+    LaunchedEffect(now.title, now.artist) {
+        announcing = true
+        delay(TITLE_SHOWN_MS)
+        announcing = false
+    }
+    val showTitle = keepTitle || announcing
+
+    val scheme = MaterialTheme.colorScheme
+    val onPill = if (selected) scheme.onPrimaryContainer else scheme.onSecondaryContainer
+    Surface(
+        modifier = modifier
+            .animateContentSize()
+            // With the title up, all the room the bar has, so as much of it shows as can.
+            .then(if (showTitle) Modifier.fillMaxWidth() else Modifier)
+            .height(44.dp),
+        shape = RoundedCornerShape(14.dp),
+        color = if (selected) scheme.primaryContainer else scheme.secondaryContainer,
+        contentColor = onPill,
+    ) {
+        Box {
+            Row(
+                Modifier.fillMaxHeight().padding(horizontal = 4.dp),
+                verticalAlignment = Alignment.CenterVertically,
+                horizontalArrangement = Arrangement.spacedBy(6.dp),
+            ) {
+                // Art (and the title while it shows) opens the full media screen.
+                Row(
+                    Modifier
+                        .then(if (showTitle) Modifier.weight(1f) else Modifier)
+                        .fillMaxHeight()
+                        .clip(RoundedCornerShape(10.dp))
+                        .clickable { navigator.media() },
+                    verticalAlignment = Alignment.CenterVertically,
+                    horizontalArrangement = Arrangement.spacedBy(8.dp),
+                ) {
+                    Box(Modifier.size(34.dp).clip(RoundedCornerShape(8.dp)).background(scheme.surfaceVariant)) {
+                        art?.let { Image(it.asImageBitmap(), null, Modifier.fillMaxSize(), contentScale = ContentScale.Crop) }
+                    }
+                    if (showTitle) {
+                        Text(
+                            nowPlayingLabel(now.title, now.artist),
+                            style = MaterialTheme.typography.titleSmall,
+                            fontWeight = FontWeight.SemiBold,
+                            maxLines = 1,
+                            overflow = TextOverflow.Ellipsis,
+                        )
+                    }
+                }
+                if (!showTitle) {
+                    GsIconButton(
+                        MediaIcons.Previous, "Previous", media::previous,
+                        enabled = now.canDo(PlaybackState.ACTION_SKIP_TO_PREVIOUS), size = 36.dp, iconSize = 22.dp,
+                    )
+                }
+                GsIconButton(
+                    if (now.playing) MediaIcons.Pause else Icons.Filled.PlayArrow,
+                    if (now.playing) "Pause" else "Play",
+                    media::togglePlay,
+                    tone = GsTone.Primary, size = 36.dp, iconSize = 22.dp,
+                )
+                if (!showTitle) {
+                    GsIconButton(
+                        MediaIcons.Next, "Next", media::next,
+                        enabled = now.canDo(PlaybackState.ACTION_SKIP_TO_NEXT), size = 36.dp, iconSize = 22.dp,
+                    )
+                }
+                GsIconButton(
+                    MediaIcons.DockRight, "Move the player beside the map", navigator::togglePlayerDock,
+                    size = 36.dp, iconSize = 22.dp,
+                )
+            }
+            if (now.durationMs > 0) {
+                // matchParentSize, so the line follows the pill's width rather than widening it.
+                Box(Modifier.matchParentSize(), contentAlignment = Alignment.BottomStart) {
+                    Box(
+                        Modifier
+                            .fillMaxWidth((position.toFloat() / now.durationMs).coerceIn(0f, 1f))
+                            .height(2.dp)
+                            .background(onPill.copy(alpha = 0.7f)),
+                    )
+                }
+            }
+        }
+    }
+}
+
+/**
+ * A filled lightning bolt, next to the battery percentage instead of the word "charging" - the
+ * core Material icon set this project ships (no extended pack, to keep the app small) has no
+ * bolt, so this is drawn rather than a vector asset.
+ */
+@Composable
+private fun ChargingGlyph(modifier: Modifier = Modifier, tint: Color = MaterialTheme.colorScheme.onSurfaceVariant) {
+    androidx.compose.foundation.Canvas(modifier) {
+        val w = size.width
+        val h = size.height
+        val bolt = androidx.compose.ui.graphics.Path().apply {
+            moveTo(w * 0.58f, 0f)
+            lineTo(w * 0.12f, h * 0.58f)
+            lineTo(w * 0.46f, h * 0.58f)
+            lineTo(w * 0.42f, h)
+            lineTo(w * 0.88f, h * 0.40f)
+            lineTo(w * 0.54f, h * 0.40f)
+            close()
+        }
+        drawPath(bolt, tint)
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarSensors.kt

@@ -5,16 +5,7 @@ import app.seb3thehacker.gearslip.Wire
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 
-/**
- * Everything the head unit's sensor channel has offered and sent, for the "Vehicle data" screen.
- *
- * [ServiceDiscovery.findSensorService] tells us which numeric sensor types this head unit is
- * willing to stream; [SensorType] names the ones publicly documented by other AA reverse-engineering
- * projects (aasdk, openauto). That mapping is carried over from other projects, not verified
- * against this exact unit, so it's a label, not a guarantee - the raw field dump next to it is
- * the ground truth. Once [onEvent] starts decoding real traffic from the 2018 Uconnect, correct
- * any type that turns out to be mislabeled.
- */
+/** Raw sensor readings, keyed by SensorBatch field number, which matches the sensor type id. */
 object CarSensors {
 
     data class Reading(val typeId: Int, val typeName: String, val raw: String, val updatedAtMs: Long)
@@ -30,16 +21,10 @@ object CarSensors {
         }
     }
 
-    /**
-     * One SensorEventIndication. Every reverse-engineered version of this message multiplexes
-     * every sensor type into one shared set of message-level field numbers (field N = "the data
-     * for sensor type N", roughly) rather than tagging events with the type id from
-     * SensorType.type - so field number is read here as a best-effort type id, same as the
-     * other services in this file.
-     */
+    /** Each SensorBatch field contains repeated readings of one sensor type. */
     fun onEvent(body: ByteArray) {
         val now = System.currentTimeMillis()
-        val fields = Wire.fields(body)
+        val fields = Wire.fields(body).filter { it.wireType == 2 }
         val byType = fields.groupBy { it.number }
         val updated = byType.mapValues { (number, group) ->
             Reading(
@@ -61,10 +46,7 @@ object CarSensors {
     }
 }
 
-/**
- * Sensor type ids as named across public Android Auto reverse-engineering references. Treated as
- * a label, not a fact - see [CarSensors] doc.
- */
+/** Sensor type values shared by the discovery service and SensorBatch. */
 object SensorType {
     private val NAMES = mapOf(
         1 to "Location (GPS)",
@@ -89,6 +71,10 @@ object SensorType {
         20 to "Gyroscope",
         21 to "GPS satellites",
         22 to "Toll card",
+        23 to "Vehicle energy model",
+        24 to "Trailer",
+        25 to "Raw vehicle energy model",
+        26 to "Raw EV trip settings",
     )
 
     fun name(id: Int): String = NAMES[id]?.let { "$it (#$id)" } ?: "Sensor #$id"

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarServices.kt

@@ -60,6 +60,13 @@ object CarServices {
     private var navStopped = false
     private var autoplayPending = false
 
+    /**
+     * The app that was playing when the driver opened another one. Opening an app is only a look
+     * at its library: until something plays there, the music carries on in this one, so leaving
+     * the new app's screen goes back to it, as Android Auto does.
+     */
+    private var stillPlaying: MediaApp? = null
+
     fun init(appContext: Context) {
         context = appContext.applicationContext
         app.seb3thehacker.gearslip.notify.CarMotion.start(appContext)
@@ -130,6 +137,8 @@ object CarServices {
         val live = phase == CarMedia.Phase.READY || phase == CarMedia.Phase.CONNECTING
         if (_mediaApp.value?.component == app.component && live) return
 
+        val previous = _mediaApp.value
+        stillPlaying = previous?.takeIf { it.component != app.component && media.now.value.playing && !autoplay }
         _mediaApp.value = app
         autoplayPending = autoplay
         media.connect(app)
@@ -151,12 +160,26 @@ object CarServices {
         return true
     }
 
+    /**
+     * The media screen closed. If nothing started in the app it showed, go back to the one that
+     * kept playing meanwhile, so the player and its buttons follow the music you can hear.
+     */
+    fun mediaScreenClosed() {
+        val back = stillPlaying ?: return
+        stillPlaying = null
+        // A track loaded here, even one paused since, means the driver used this app.
+        if (media.now.value.playing || media.now.value.title.isNotEmpty()) return
+        app.seb3thehacker.gearslip.GearslipLog.i("media: nothing played in ${_mediaApp.value?.label}, back to ${back.label}")
+        openMedia(back)
+    }
+
     /** Closes the media app from the car: stops what it's playing and drops the connection. */
     fun closeMedia() {
         if (media.now.value.playing) media.togglePlay()
         media.disconnect()
         _mediaApp.value = null
         autoplayPending = false
+        stillPlaying = null
     }
 
     /** Called once the media app is connected: starts playback if that was asked for. */

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarSettings.kt

@@ -18,6 +18,33 @@ enum class Units { AUTO, IMPERIAL, METRIC }
 /** The car UI's own colours. Separate from [NightMode], which is about the light outside (the map). */
 enum class AppTheme { PHONE, LIGHT, DARK }
 
+/** A screen's width and height in pixels, as someone typed it: "1280x480". */
+data class ScreenSize(val width: Int, val height: Int) {
+    override fun toString() = "${width}x$height"
+
+    companion object {
+        fun parse(text: String?): ScreenSize? {
+            val parts = text?.lowercase()?.split('x', '×', ' ')?.filter { it.isNotBlank() } ?: return null
+            if (parts.size != 2) return null
+            val w = parts[0].trim().toIntOrNull() ?: return null
+            val h = parts[1].trim().toIntOrNull() ?: return null
+            return if (w in 100..8000 && h in 100..8000) ScreenSize(w, h) else null
+        }
+    }
+}
+
+/**
+ * How a head unit puts our frame on a screen of another shape. [CROP] cuts the edges off, as
+ * a car's own margins do; [SQUASH] shrinks the whole frame to fit, stretching everything.
+ */
+enum class ScreenFit { CROP, SQUASH }
+
+/** What size the phone's car preview draws: the last car's, this device's whole screen, or one typed in. */
+enum class PreviewSize { LAST_CAR, FILL, CUSTOM }
+
+/** When the nav bar gets out of the way: never, during a route, or whenever the map is up. */
+enum class NavBarMode { SHOW, HIDE_NAVIGATING, HIDE }
+
 /**
  * Settings changed from the car screen itself. Held as flows so the car UI reacts the moment a
  * button is tapped, and persisted through [AppSettings] so they survive the next connection.
@@ -36,6 +63,7 @@ private const val KEY_LOCATION_WARNING = "car_location_warning"
     private const val KEY_LAST_MEDIA = "car_last_media"
     private const val KEY_AUTOPLAY = "car_autoplay"
     private const val KEY_PLAYER_TITLE = "car_player_title"
+    private const val KEY_PLAYER_LEFT = "car_player_left"
     private const val KEY_THEME = "car_app_theme"
     private const val KEY_UI_THEME = "car_ui_theme"
     private const val KEY_PINNED = "car_pinned_apps"
@@ -43,8 +71,15 @@ private const val KEY_LOCATION_WARNING = "car_location_warning"
     private const val KEY_EXPERIMENTAL_FEATURES = "car_experimental_features"
     private const val KEY_SYSTEM_SPEECH = "car_system_speech"
     private const val KEY_CAR_SENSORS = "car_sensors_enabled"
+    private const val KEY_ADAPTIVE_VIDEO = "adaptive_video_enabled"
+    private const val KEY_DEBUG_BADGE = "debug_badge"
     private const val KEY_SEEN_SAFETY_WARNING = "car_seen_safety_warning"
     private const val KEY_UNITS = "car_units"
+    private const val KEY_NAV_BAR = "car_nav_bar"
+    private const val KEY_SCREEN_SIZE = "car_screen_size"
+    private const val KEY_SCREEN_FIT = "car_screen_fit"
+    private const val KEY_PREVIEW_SIZE = "preview_size"
+    private const val KEY_PREVIEW_CUSTOM = "preview_custom_size"
     private const val KEY_WHATS_NEW = "car_whats_new_after_updates"
     private const val KEY_WHATS_NEW_SEEN = "car_whats_new_seen_code"
 
@@ -68,6 +103,7 @@ private const val KEY_LOCATION_WARNING = "car_location_warning"
     private val lastMediaFlow = MutableStateFlow<String?>(null)
     private val autoplayFlow = MutableStateFlow(false)
     private val playerTitleFlow = MutableStateFlow(false)
+    private val playerLeftFlow = MutableStateFlow(false)
     private val themeFlow = MutableStateFlow(AppTheme.PHONE)
     val appTheme: StateFlow<AppTheme> = themeFlow
     private val uiThemeFlow = MutableStateFlow(GsThemes.default.id)
@@ -79,11 +115,50 @@ private const val KEY_LOCATION_WARNING = "car_location_warning"
     private val experimentalFeaturesFlow = MutableStateFlow(false)
     private val systemSpeechFlow = MutableStateFlow(false)
     private val carSensorsFlow = MutableStateFlow(false)
+    private val adaptiveVideoFlow = MutableStateFlow(false)
+    private val debugBadgeFlow = MutableStateFlow(true)
     private val seenSafetyWarningFlow = MutableStateFlow(false)
     private val unitsFlow = MutableStateFlow(Units.AUTO)
 
     val units: StateFlow<Units> = unitsFlow
 
+    private val screenSizeFlow = MutableStateFlow<ScreenSize?>(null)
+    private val screenFitFlow = MutableStateFlow(ScreenFit.CROP)
+    private val previewSizeFlow = MutableStateFlow(PreviewSize.LAST_CAR)
+    private val previewCustomFlow = MutableStateFlow<ScreenSize?>(null)
+
+    /** The car screen's real size, when the head unit gets it wrong; null trusts the head unit. */
+    val screenSize: StateFlow<ScreenSize?> = screenSizeFlow
+    val screenFit: StateFlow<ScreenFit> = screenFitFlow
+    val previewSize: StateFlow<PreviewSize> = previewSizeFlow
+    val previewCustom: StateFlow<ScreenSize?> = previewCustomFlow
+
+    /** Takes effect the next time the car connects: the video size is agreed at the start. */
+    fun setScreenSize(size: ScreenSize?) {
+        screenSizeFlow.value = size
+        AppSettings.putString(app, KEY_SCREEN_SIZE, size?.toString().orEmpty())
+    }
+
+    fun setScreenFit(fit: ScreenFit) {
+        screenFitFlow.value = fit
+        AppSettings.putString(app, KEY_SCREEN_FIT, fit.name)
+    }
+
+    fun setPreviewSize(size: PreviewSize, custom: ScreenSize? = previewCustomFlow.value) {
+        previewSizeFlow.value = size
+        previewCustomFlow.value = custom
+        AppSettings.putString(app, KEY_PREVIEW_SIZE, size.name)
+        AppSettings.putString(app, KEY_PREVIEW_CUSTOM, custom?.toString().orEmpty())
+    }
+
+    private val navBarFlow = MutableStateFlow(NavBarMode.SHOW)
+    val navBarMode: StateFlow<NavBarMode> = navBarFlow
+
+    fun setNavBarMode(mode: NavBarMode) {
+        navBarFlow.value = mode
+        AppSettings.putString(app, KEY_NAV_BAR, mode.name)
+    }
+
 
     private val whatsNewFlow = MutableStateFlow(true)
     private val whatsNewSeenFlow = MutableStateFlow(0)
@@ -146,6 +221,9 @@ private const val KEY_LOCATION_WARNING = "car_location_warning"
      */
     val playerTitle: StateFlow<Boolean> = playerTitleFlow
 
+    /** The home screen's player sits left of the map instead of right of it. */
+    val playerLeft: StateFlow<Boolean> = playerLeftFlow
+
     val scale: StateFlow<Float> = scaleFlow
     val openOnConnect: StateFlow<String> = openFlow
     val nightMode: StateFlow<NightMode> = nightFlow
@@ -198,6 +276,20 @@ private const val KEY_LOCATION_WARNING = "car_location_warning"
      */
     val carSensorsEnabled: StateFlow<Boolean> = carSensorsFlow
 
+    /**
+     * Video bitrate that backs off when the car, or the Wi-Fi to it, falls behind. Takes effect
+     * only while [experimentalFeaturesEnabled] is on too; untested in a car so far.
+     */
+    val adaptiveVideoEnabled: StateFlow<Boolean> = adaptiveVideoFlow
+
+    /** Debug builds only: the car screen's DEBUG BUILD badge, which screenshots for the README leave out. */
+    val debugBadge: StateFlow<Boolean> = debugBadgeFlow
+
+    fun setDebugBadge(on: Boolean) {
+        debugBadgeFlow.value = on
+        AppSettings.putString(app, KEY_DEBUG_BADGE, on.toString())
+    }
+
     /**
      * Whether the car screen's own "drive safely" warning has already been shown and dismissed
      * once, from this same install. Separate from the phone side's own compat/safety dialogs -
@@ -223,6 +315,7 @@ private const val KEY_LOCATION_WARNING = "car_location_warning"
         uiThemeFlow.value = AppSettings.getString(app, KEY_UI_THEME, GsThemes.default.id)
         autoplayFlow.value = AppSettings.getString(app, KEY_AUTOPLAY, "false") == "true"
         playerTitleFlow.value = AppSettings.getString(app, KEY_PLAYER_TITLE, "false") == "true"
+        playerLeftFlow.value = AppSettings.getString(app, KEY_PLAYER_LEFT, "false") == "true"
         pipeAudioFlow.value = AppSettings.getString(app, KEY_PIPE_AUDIO, "true") == "true"
         // Until the driver sets it, on for USB audio and off for Bluetooth, where the map app's
         // own voice already reaches the car.
@@ -239,10 +332,23 @@ private const val KEY_LOCATION_WARNING = "car_location_warning"
         experimentalFeaturesFlow.value = AppSettings.getString(app, KEY_EXPERIMENTAL_FEATURES, "false") == "true"
         systemSpeechFlow.value = AppSettings.getString(app, KEY_SYSTEM_SPEECH, "false") == "true"
         carSensorsFlow.value = AppSettings.getString(app, KEY_CAR_SENSORS, "false") == "true"
+        adaptiveVideoFlow.value = AppSettings.getString(app, KEY_ADAPTIVE_VIDEO, "false") == "true"
+        debugBadgeFlow.value = AppSettings.getString(app, KEY_DEBUG_BADGE, "true") == "true"
         seenSafetyWarningFlow.value = AppSettings.getString(app, KEY_SEEN_SAFETY_WARNING, "false") == "true"
         unitsFlow.value = runCatching {
             Units.valueOf(AppSettings.getString(app, KEY_UNITS, Units.AUTO.name))
         }.getOrDefault(Units.AUTO)
+        screenSizeFlow.value = ScreenSize.parse(AppSettings.getString(app, KEY_SCREEN_SIZE, ""))
+        screenFitFlow.value = runCatching {
+            ScreenFit.valueOf(AppSettings.getString(app, KEY_SCREEN_FIT, ScreenFit.CROP.name))
+        }.getOrDefault(ScreenFit.CROP)
+        previewSizeFlow.value = runCatching {
+            PreviewSize.valueOf(AppSettings.getString(app, KEY_PREVIEW_SIZE, PreviewSize.LAST_CAR.name))
+        }.getOrDefault(PreviewSize.LAST_CAR)
+        previewCustomFlow.value = ScreenSize.parse(AppSettings.getString(app, KEY_PREVIEW_CUSTOM, ""))
+        navBarFlow.value = runCatching {
+            NavBarMode.valueOf(AppSettings.getString(app, KEY_NAV_BAR, NavBarMode.SHOW.name))
+        }.getOrDefault(NavBarMode.SHOW)
         whatsNewFlow.value = AppSettings.getString(app, KEY_WHATS_NEW, "true") == "true"
         whatsNewSeenFlow.value = AppSettings.getString(app, KEY_WHATS_NEW_SEEN, "0").toIntOrNull() ?: 0
     }
@@ -282,6 +388,11 @@ private const val KEY_LOCATION_WARNING = "car_location_warning"
         AppSettings.putString(app, KEY_PLAYER_TITLE, on.toString())
     }
 
+    fun setPlayerLeft(on: Boolean) {
+        playerLeftFlow.value = on
+        AppSettings.putString(app, KEY_PLAYER_LEFT, on.toString())
+    }
+
     fun setAutoplay(on: Boolean) {
         autoplayFlow.value = on
         AppSettings.putString(app, KEY_AUTOPLAY, on.toString())
@@ -325,6 +436,11 @@ private const val KEY_LOCATION_WARNING = "car_location_warning"
         AppSettings.putString(app, KEY_SYSTEM_SPEECH, on.toString())
     }
 
+    fun setAdaptiveVideoEnabled(on: Boolean) {
+        adaptiveVideoFlow.value = on
+        AppSettings.putString(app, KEY_ADAPTIVE_VIDEO, on.toString())
+    }
+
     fun setCarSensorsEnabled(on: Boolean) {
         carSensorsFlow.value = on
         AppSettings.putString(app, KEY_CAR_SENSORS, on.toString())

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarSettingsScreen.kt

@@ -5,12 +5,15 @@ import app.seb3thehacker.gearslip.car.theme.*
 import android.os.Build
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.verticalScroll
@@ -51,6 +54,9 @@ fun CarSettingsScreen() {
     val open by CarSettings.openOnConnect.collectAsState()
     val night by CarSettings.nightMode.collectAsState()
     val units by CarSettings.units.collectAsState()
+    val navBar by CarSettings.navBarMode.collectAsState()
+    val screenSize by CarSettings.screenSize.collectAsState()
+    val screenFit by CarSettings.screenFit.collectAsState()
     val whatsNew by CarSettings.whatsNewAfterUpdates.collectAsState()
     val pipeAudio by CarSettings.pipeAudio.collectAsState()
     val speakDirections by CarSettings.speakDirections.collectAsState()
@@ -58,10 +64,12 @@ fun CarSettingsScreen() {
     val locationWarning by CarSettings.locationWarning.collectAsState()
     val autoplay by CarSettings.autoplay.collectAsState()
     val playerTitle by CarSettings.playerTitle.collectAsState()
+    val playerLeft by CarSettings.playerLeft.collectAsState()
     val theme by CarSettings.appTheme.collectAsState()
     val uiTheme by CarSettings.uiTheme.collectAsState()
     val experimentalFeatures by CarSettings.experimentalFeaturesEnabled.collectAsState()
     val carSensors by CarSettings.carSensorsEnabled.collectAsState()
+    val adaptiveVideo by CarSettings.adaptiveVideoEnabled.collectAsState()
     val systemSpeech by CarSettings.systemSpeech.collectAsState()
     val display by CarEnvironment.display.collectAsState()
     val vehicle by CarEnvironment.vehicle.collectAsState()
@@ -70,140 +78,233 @@ fun CarSettingsScreen() {
         value = withContext(Dispatchers.Default) { CertSummary.read(context) }
     }
 
-    Column(
-        Modifier
-            .fillMaxSize()
-            .verticalScroll(rememberScrollState())
-            .padding(horizontal = 24.dp, vertical = 16.dp),
+    LazyColumn(
+        Modifier.fillMaxSize(),
+        // Built as it scrolls into view rather than all at once: every row here is a set of
+        // buttons, and building the whole screen made opening Settings visibly slow.
+        contentPadding = PaddingValues(horizontal = 24.dp, vertical = 16.dp),
         verticalArrangement = Arrangement.spacedBy(20.dp),
     ) {
-        ScreenHeader("Settings")
+        item {
+            ScreenHeader("Settings")
+        }
 
-        ChoiceRow(
-            "Open on connect",
-            listOf(CarSettings.HOME to "Home") + CarApps.all.filter { it.id != "settings" }.map { it.id to it.label },
-            open,
-        ) { CarSettings.setOpenOnConnect(it) }
+        item { Group("Screen") }
 
-        ChoiceRow(
-            "Size",
-            listOf(1f to "Normal", 1.25f to "Large", 1.5f to "Extra large"),
-            scale,
-        ) { CarSettings.setScale(it) }
+        item {
+            ChoiceRow(
+                "Open on connect",
+                listOf(CarSettings.HOME to "Home") + CarApps.all.filter { it.id != "settings" }.map { it.id to it.label },
+                open,
+            ) { CarSettings.setOpenOnConnect(it) }
+        }
 
-        ChoiceRow(
-            "App theme",
-            listOf(AppTheme.PHONE to "Follow phone", AppTheme.LIGHT to "Light", AppTheme.DARK to "Dark"),
-            theme,
-        ) { CarSettings.setAppTheme(it) }
+        item {
+            ChoiceRow(
+                "Size",
+                listOf(1f to "Normal", 1.25f to "Large", 1.5f to "Extra large"),
+                scale,
+            ) { CarSettings.setScale(it) }
+        }
 
-        ChoiceRow(
-            "Theme",
-            GsThemes.builtIn.map { it.id to it.name },
-            uiTheme,
-        ) { CarSettings.setUiTheme(it) }
+        item {
+            ChoiceRow(
+                "App theme",
+                listOf(AppTheme.PHONE to "Follow phone", AppTheme.LIGHT to "Light", AppTheme.DARK to "Dark"),
+                theme,
+            ) { CarSettings.setAppTheme(it) }
+        }
 
-        ChoiceRow(
-            "Map day/night",
-            listOf(NightMode.AUTO to "Auto", NightMode.DAY to "Day", NightMode.NIGHT to "Night"),
-            night,
-        ) { CarSettings.setNightMode(it) }
+        item {
+            ChoiceRow(
+                "Theme",
+                GsThemes.builtIn.map { it.id to it.name },
+                uiTheme,
+            ) { CarSettings.setUiTheme(it) }
+        }
 
-        ChoiceRow(
-            "Units",
-            listOf(Units.AUTO to "Auto", Units.IMPERIAL to "Imperial (mi, ft, °F)", Units.METRIC to "Metric (km, m, °C)"),
-            units,
-        ) { CarSettings.setUnits(it) }
+        item {
+            ChoiceRow(
+                "Map day/night",
+                listOf(NightMode.AUTO to "Auto", NightMode.DAY to "Day", NightMode.NIGHT to "Night"),
+                night,
+            ) { CarSettings.setNightMode(it) }
+        }
 
-        ChoiceRow(
-            "Player in the nav bar",
-            listOf(false to "Skip buttons", true to "Song title"),
-            playerTitle,
-        ) { CarSettings.setPlayerTitle(it) }
+        item {
+            ChoiceRow(
+                "Units",
+                listOf(Units.AUTO to "Auto", Units.IMPERIAL to "Imperial (mi, ft, °F)", Units.METRIC to "Metric (km, m, °C)"),
+                units,
+            ) { CarSettings.setUnits(it) }
+        }
 
-        ChoiceRow(
-            "Autoplay on connect",
-            listOf(false to "Off", true to "On"),
-            autoplay,
-        ) { CarSettings.setAutoplay(it) }
+        // For a head unit that reports the wrong size and stretches the picture (issue #12).
+        item {
+            ChoiceRow(
+                "Screen size (next connection)",
+                listOf<ScreenSize?>(null).plus(SCREEN_PRESETS).plus(screenSize).distinct()
+                    .map { it to (it?.toString() ?: "From the car") },
+                screenSize,
+            ) { CarSettings.setScreenSize(it) }
+        }
 
-        ChoiceRow(
-            "Car audio",
-            listOf(false to "Bluetooth", true to "USB"),
-            pipeAudio,
-        ) { CarSettings.setPipeAudio(it) }
-        Text(
-            "USB sends the phone's sound through Gearslip. Android asks to share your screen each " +
-                "drive, and a few apps block it. Bluetooth plays as the phone normally would, and " +
-                "Android never asks.",
-            style = MaterialTheme.typography.bodySmall,
-            color = MaterialTheme.colorScheme.onSurfaceVariant,
-        )
-        if (!pipeAudio) {
+        if (screenSize != null) item {
+            ChoiceRow(
+                "Fit to the screen",
+                listOf(ScreenFit.CROP to "Crop the edges", ScreenFit.SQUASH to "Squash to fit"),
+                screenFit,
+            ) { CarSettings.setScreenFit(it) }
+        }
+
+        item { Group("Nav bar and player") }
+
+        item {
+            ChoiceRow(
+                "Nav bar",
+                listOf(
+                    NavBarMode.SHOW to "Always show",
+                    NavBarMode.HIDE_NAVIGATING to "Hide while navigating",
+                    NavBarMode.HIDE to "Hide until tapped",
+                ),
+                navBar,
+            ) { CarSettings.setNavBarMode(it) }
+        }
+
+        item {
+            ChoiceRow(
+                "Player in the nav bar",
+                listOf(false to "Skip buttons", true to "Song title"),
+                playerTitle,
+            ) { CarSettings.setPlayerTitle(it) }
+        }
+
+        item {
+            ChoiceRow(
+                "Player beside the map",
+                listOf(false to "Right", true to "Left"),
+                playerLeft,
+            ) { CarSettings.setPlayerLeft(it) }
+        }
+
+        item {
+            ChoiceRow(
+                "Autoplay on connect",
+                listOf(false to "Off", true to "On"),
+                autoplay,
+            ) { CarSettings.setAutoplay(it) }
+        }
+
+        item { Group("Sound and voice") }
+
+        item {
+            ChoiceRow(
+                "Car audio",
+                listOf(false to "Bluetooth", true to "USB"),
+                pipeAudio,
+            ) { CarSettings.setPipeAudio(it) }
+        }
+
+        item {
+            Text(
+                "USB sends the phone's sound through Gearslip. Android asks to share your screen each " +
+                    "drive, and a few apps block it. Bluetooth plays as the phone normally would, and " +
+                    "Android never asks.",
+                style = MaterialTheme.typography.bodySmall,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+        }
+
+        item { Group("Warnings") }
+
+        if (!pipeAudio) item {
             ChoiceRow(
                 "Warn when Bluetooth isn't connected",
                 listOf(false to "Off", true to "On"),
                 bluetoothWarning,
             ) { CarSettings.setBluetoothWarning(it) }
         }
-        ChoiceRow(
-            "Warn when location is off",
-            listOf(false to "Off", true to "On"),
-            locationWarning,
-        ) { CarSettings.setLocationWarning(it) }
 
-        ChoiceRow(
-            "Spoken directions",
-            listOf(false to "Off", true to "On"),
-            speakDirections,
-        ) { CarSettings.setSpeakDirections(it) }
-        Text(
-            "Gearslip reads each turn aloud through the car's speakers, and the music dips while it " +
-                "speaks. Turn it off if your map app's own voice already plays in the car.",
-            style = MaterialTheme.typography.bodySmall,
-            color = MaterialTheme.colorScheme.onSurfaceVariant,
-        )
-
-        ExperimentalFeatureRow(
-            title = "Use the phone's speech recognition",
-            description = "Listens through the phone's own speech service instead of Gearslip's. On " +
-                "most phones that's Google's, which may send your voice to Google. GrapheneOS has " +
-                "none, so Gearslip keeps using its own.",
-            checked = systemSpeech,
-        ) { CarSettings.setSystemSpeech(it) }
-
-        WebPageSetting()
-
-        ScreenFit(vehicle)
-
-        ChoiceRow(
-            "Experimental features",
-            listOf(false to "Hide", true to "Show"),
-            experimentalFeatures,
-        ) { CarSettings.setExperimentalFeaturesEnabled(it) }
-        if (experimentalFeatures) {
-            ExperimentalFeaturesList(carSensors)
+        item {
+            ChoiceRow(
+                "Warn when location is off",
+                listOf(false to "Off", true to "On"),
+                locationWarning,
+            ) { CarSettings.setLocationWarning(it) }
         }
 
-        Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
-            Text("Connection", style = MaterialTheme.typography.titleMedium, color = MaterialTheme.colorScheme.primary)
-            Info("Phone", "${Build.MANUFACTURER} ${Build.MODEL}")
-            Info("Vehicle", vehicle.ifEmpty { "-" })
-            Info("Video", display.ifEmpty { "-" })
-            Info("Certificate", cert?.headline ?: "Checking…")
+        item {
+            ChoiceRow(
+                "Spoken directions",
+                listOf(false to "Off", true to "On"),
+                speakDirections,
+            ) { CarSettings.setSpeakDirections(it) }
         }
 
-        Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
-            Text("About", style = MaterialTheme.typography.titleMedium, color = MaterialTheme.colorScheme.primary)
-            Info("Version", app.seb3thehacker.gearslip.BuildConfig.VERSION_NAME)
-            Info("Build", app.seb3thehacker.gearslip.BuildConfig.VERSION_CODE.toString())
+        item {
+            Text(
+                "Gearslip reads each turn aloud through the car's speakers, and the music dips while it " +
+                    "speaks. Turn it off if your map app's own voice already plays in the car.",
+                style = MaterialTheme.typography.bodySmall,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+        }
+
+        item {
             ExperimentalFeatureRow(
-                "What's new after updates",
-                "Show the list of changes once, the first time the car connects after an update.",
-                whatsNew,
-            ) { CarSettings.setWhatsNewAfterUpdates(it) }
-            GsButton(onClick = CarSettings::openWhatsNew, tone = GsTone.Tonal, modifier = Modifier.height(56.dp)) {
-                Text("What's new", style = MaterialTheme.typography.titleMedium)
+                title = "Use the phone's speech recognition",
+                description = "Listens through the phone's own speech service instead of Gearslip's. On " +
+                    "most phones that's Google's, which may send your voice to Google. GrapheneOS has " +
+                    "none, so Gearslip keeps using its own.",
+                checked = systemSpeech,
+            ) { CarSettings.setSystemSpeech(it) }
+        }
+
+        item { Group("More") }
+
+        item {
+            WebPageSetting()
+        }
+
+        item {
+            ScreenFit(vehicle)
+        }
+
+        item {
+            ChoiceRow(
+                "Experimental features",
+                listOf(false to "Hide", true to "Show"),
+                experimentalFeatures,
+            ) { CarSettings.setExperimentalFeaturesEnabled(it) }
+        }
+
+        if (experimentalFeatures) item {
+            ExperimentalFeaturesList(carSensors, adaptiveVideo)
+        }
+
+        item {
+            Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                Text("Connection", style = MaterialTheme.typography.titleMedium, color = MaterialTheme.colorScheme.primary)
+                Info("Phone", "${Build.MANUFACTURER} ${Build.MODEL}")
+                Info("Vehicle", vehicle.ifEmpty { "-" })
+                Info("Video", display.ifEmpty { "-" })
+                Info("Certificate", cert?.headline ?: "Checking…")
+            }
+        }
+
+        item {
+            Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                Text("About", style = MaterialTheme.typography.titleMedium, color = MaterialTheme.colorScheme.primary)
+                Info("Version", app.seb3thehacker.gearslip.BuildConfig.VERSION_NAME)
+                Info("Build", app.seb3thehacker.gearslip.BuildConfig.VERSION_CODE.toString())
+                ExperimentalFeatureRow(
+                    "What's new after updates",
+                    "Show the list of changes once, the first time the car connects after an update.",
+                    whatsNew,
+                ) { CarSettings.setWhatsNewAfterUpdates(it) }
+                GsButton(onClick = CarSettings::openWhatsNew, tone = GsTone.Tonal, modifier = Modifier.height(56.dp)) {
+                    Text("What's new", style = MaterialTheme.typography.titleMedium)
+                }
             }
         }
     }
@@ -211,8 +312,37 @@ fun CarSettingsScreen() {
 
 @Composable
 private fun <T> ChoiceRow(title: String, options: List<Pair<T, String>>, selected: T, onSelect: (T) -> Unit) {
-    Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
-        Text(title, style = MaterialTheme.typography.titleMedium, color = MaterialTheme.colorScheme.primary)
+    // On a wide screen the name sits beside its choices, which halves how far there is to scroll.
+    androidx.compose.foundation.layout.BoxWithConstraints(Modifier.fillMaxWidth()) {
+        if (maxWidth >= 720.dp && options.size <= 4) {
+            Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(16.dp)) {
+                Text(title, style = MaterialTheme.typography.titleMedium, modifier = Modifier.weight(0.3f))
+                Box(Modifier.weight(0.7f)) { ChoiceButtons(options, selected, onSelect) }
+            }
+        } else {
+            Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                Text(title, style = MaterialTheme.typography.titleMedium)
+                ChoiceButtons(options, selected, onSelect)
+            }
+        }
+    }
+}
+
+/** A group of settings: a heading, so a long list reads as a few short ones. */
+@Composable
+private fun Group(title: String) {
+    Text(
+        title,
+        style = MaterialTheme.typography.titleLarge,
+        fontWeight = FontWeight.Bold,
+        color = MaterialTheme.colorScheme.primary,
+        modifier = Modifier.padding(top = 12.dp),
+    )
+}
+
+@Composable
+private fun <T> ChoiceButtons(options: List<Pair<T, String>>, selected: T, onSelect: (T) -> Unit) {
+    run {
         Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(12.dp)) {
             options.forEach { (value, label) ->
                 val on = value == selected
@@ -239,7 +369,7 @@ private fun <T> ChoiceRow(title: String, options: List<Pair<T, String>>, selecte
  * so the list reads fine whether there's one entry or several.
  */
 @Composable
-private fun ExperimentalFeaturesList(carSensors: Boolean) {
+private fun ExperimentalFeaturesList(carSensors: Boolean, adaptiveVideo: Boolean) {
     Column(
         Modifier.fillMaxWidth(),
         verticalArrangement = Arrangement.spacedBy(10.dp),
@@ -252,6 +382,12 @@ private fun ExperimentalFeaturesList(carSensors: Boolean) {
                 "guess, not a fact, until you've watched one change for yourself.",
             checked = carSensors,
         ) { CarSettings.setCarSensorsEnabled(it) }
+        ExperimentalFeatureRow(
+            title = "Adaptive video quality",
+            description = "Lowers the picture's quality when the car, or its Wi-Fi, can't keep " +
+                "up, and raises it again once it can. Takes effect on the next connection.",
+            checked = adaptiveVideo,
+        ) { CarSettings.setAdaptiveVideoEnabled(it) }
     }
 }
 
@@ -406,3 +542,8 @@ private fun StepButton(text: String, modifier: Modifier, onClick: () -> Unit) {
     }
 }
 
+/** Common car screen sizes; Settings on the phone takes any other. */
+private val SCREEN_PRESETS = listOf(
+    ScreenSize(800, 480), ScreenSize(1024, 600), ScreenSize(1280, 480), ScreenSize(1280, 720),
+    ScreenSize(1440, 540), ScreenSize(1920, 720), ScreenSize(1920, 1080),
+)

gearslip/src/main/java/app/seb3thehacker/gearslip/car/CarUi.kt

@@ -1,5 +1,8 @@
 package app.seb3thehacker.gearslip.car
 
+import androidx.compose.material.icons.filled.Call
+import app.seb3thehacker.gearslip.call.CarCalls
+import app.seb3thehacker.gearslip.call.CallUiState
 import androidx.compose.foundation.Image
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.LocalIndication
@@ -72,6 +75,7 @@ import androidx.compose.ui.res.vectorResource
 import androidx.compose.ui.text.style.TextOverflow
 import app.seb3thehacker.gearslip.R
 import app.seb3thehacker.gearslip.car.theme.GsColors
+import app.seb3thehacker.gearslip.car.theme.withTintedSurfaces
 import app.seb3thehacker.gearslip.car.theme.GsIconBox
 import app.seb3thehacker.gearslip.car.theme.GsIconButton
 import app.seb3thehacker.gearslip.car.theme.GsButton
@@ -114,7 +118,7 @@ fun CarUi() {
         AppTheme.LIGHT -> false
         AppTheme.DARK -> true
     }
-    val colors = if (dark) dynamicDarkColorScheme(appContext) else dynamicLightColorScheme(appContext)
+    val colors = (if (dark) dynamicDarkColorScheme(appContext) else dynamicLightColorScheme(appContext)).withTintedSurfaces(dark)
     val base = LocalDensity.current
     val insets by CarEnvironment.insets.collectAsState()
     val navigator = remember { CarNavigator(CarSettings.openOnConnect.value) }
@@ -123,6 +127,7 @@ fun CarUi() {
         while (true) {
             delay(250)
             controlsWake.tick()
+            CarFullscreen.tick()
         }
     }
     // The knob counts as a touch: the map's buttons can't be found while they're faded out.
@@ -193,10 +198,25 @@ fun CarUi() {
                     .fillMaxSize()
                     // Watches every touch without taking any: first in line, consumes nothing.
                     .pointerInput(controlsWake) {
+                        // In full screen, a swipe that starts at the top or bottom edge brings the
+                        // nav bar back. Only from the very edge, so scrolling a page still scrolls.
+                        val edge = 32.dp.toPx()
+                        val slop = 24.dp.toPx()
+                        var startY = -1f
                         awaitPointerEventScope {
                             while (true) {
-                                awaitPointerEvent(PointerEventPass.Initial)
+                                val event = awaitPointerEvent(PointerEventPass.Initial)
                                 controlsWake.touch()
+                                CarFullscreen.touch()
+                                val change = event.changes.firstOrNull() ?: continue
+                                if (!CarFullscreen.active) continue
+                                if (change.pressed && !change.previousPressed) {
+                                    val y = change.position.y
+                                    startY = if (y < edge || y > size.height - edge) y else -1f
+                                } else if (startY >= 0f && change.pressed && kotlin.math.abs(change.position.y - startY) > slop) {
+                                    CarFullscreen.reveal()
+                                    startY = -1f
+                                }
                             }
                         }
                     },
@@ -211,6 +231,26 @@ fun CarUi() {
                 }
                 val screen = navigator.current
                 val safetyWarningSeen by CarSettings.hasSeenSafetyWarning.collectAsState()
+                val keyboardVisible by CarKeyboardVisibility.state
+                // Off "Always show", the bar floats over the map rather than taking a row of its
+                // own: hiding it then leaves the map's surface the size it was. Resizing it would
+                // hand the map app a new surface each time, and some go black on that.
+                val navBarMode by CarSettings.navBarMode.collectAsState()
+                val appTemplate by CarServices.nav.template.collectAsState()
+                val floatingBar = navBarMode != NavBarMode.SHOW
+                val barMayHide = screen == CarScreen.Home && when (navBarMode) {
+                    NavBarMode.SHOW -> false
+                    NavBarMode.HIDE_NAVIGATING -> appTemplate is androidx.car.app.navigation.model.NavigationTemplate
+                    NavBarMode.HIDE -> true
+                }
+                // A full wait from when hiding becomes possible, not from whenever the last touch was.
+                LaunchedEffect(barMayHide) { if (barMayHide) controlsWake.touch() }
+                // A call keeps the bar up whatever the setting: End and Mute live on it.
+                val onCall = CarCalls.state.collectAsState().value is CallUiState.Active
+                val barShown = !keyboardVisible && (!barMayHide || controlsWake.navBarAwake || onCall)
+                val homeInset = if (floatingBar && barShown) NAV_BAR_HEIGHT else 0.dp
+                // Only the screen that asked: going Home or anywhere else ends it.
+                val fullscreen = CarFullscreen.active && screen != CarScreen.Home
                 Box(Modifier.fillMaxSize().padding(pad)) {
                 Column(Modifier.fillMaxSize()) {
                     if (!safetyWarningSeen) {
@@ -223,12 +263,29 @@ fun CarUi() {
                         // Home never leaves the composition; other screens cover it. Dropping it
                         // would tear down the map's surface, and coming back would then show black
                         // while the nav app redrew on a new one.
-                        CarHome()
+                        CompositionLocalProvider(LocalNavBarInset provides homeInset) { CarHome() }
+                    }
+                    // The keyboard takes the nav bar's row instead of squeezing in above it -
+                    // nothing on the nav bar is useful mid-type, and the screen is too small to
+                    // show both.
+                    if (!floatingBar && !keyboardVisible) CarNavBar(navigator)
+                }
+                // Every other screen, and everything that pops up, in a layer over Home rather
+                // than inside its area: full screen grows this layer over the nav bar's row while
+                // Home, and the map's surface in it, keeps its size.
+                if (safetyWarningSeen) {
+                    Box(
+                        Modifier
+                            .fillMaxSize()
+                            .padding(bottom = if (!floatingBar && !keyboardVisible && !fullscreen) NAV_BAR_HEIGHT else 0.dp),
+                    ) {
                         if (screen != CarScreen.Home) {
                             Box(
                                 Modifier
                                     .fillMaxSize()
                                     .background(MaterialTheme.colorScheme.background)
+                                    // The floating bar never hides here, so keep the screen clear of it.
+                                    .padding(bottom = if (floatingBar && !keyboardVisible && !fullscreen) NAV_BAR_HEIGHT else 0.dp)
                                     // Keeps touches that miss this screen's controls off the map.
                                     .pointerInput(Unit) { detectTapGestures { } },
                             ) {
@@ -247,7 +304,7 @@ fun CarUi() {
                                 }
                             }
                         }
-                        CarToastOverlay(Modifier.align(Alignment.BottomCenter))
+                        CarToastOverlay(Modifier.align(Alignment.BottomCenter).padding(bottom = homeInset))
                         CallPromptOverlay()
                         BluetoothPairOverlay()
                         PopupTimer()
@@ -258,21 +315,39 @@ fun CarUi() {
                         )
                         // Above the popup: a call is more urgent than any notification.
                         VoiceHelpOverlay(Modifier.align(Alignment.Center))
-                        CallOverlay(Modifier.align(Alignment.TopCenter))
-                        AssistantOverlay(Modifier.align(Alignment.BottomCenter))
-                        if (app.seb3thehacker.gearslip.BuildConfig.DEBUG) {
+                        CallOverlay()
+                        AssistantOverlay(Modifier.align(Alignment.BottomCenter).padding(bottom = homeInset))
+                        val badge by CarSettings.debugBadge.collectAsState()
+                        if (app.seb3thehacker.gearslip.BuildConfig.DEBUG && badge) {
                             // Bottom corner, not top: a screen's own header almost always puts
                             // something in the top-right (settings, search, a Liked Songs
                             // shortcut) and this badge used to sit right on top of it, hiding
                             // whatever the screen drew there.
-                            DebugBuildBadge(Modifier.align(Alignment.BottomEnd))
+                            DebugBuildBadge(Modifier.align(Alignment.BottomEnd).padding(bottom = homeInset))
+                        }
+                        if (floatingBar || fullscreen) {
+                            androidx.compose.animation.AnimatedVisibility(
+                                if (fullscreen) CarFullscreen.revealed || onCall else barShown,
+                                Modifier.align(Alignment.BottomCenter),
+                                enter = androidx.compose.animation.slideInVertically { it },
+                                exit = androidx.compose.animation.slideOutVertically { it },
+                            ) { CarNavBar(navigator) }
+                        }
+                        if (fullscreen) {
+                            androidx.compose.animation.AnimatedVisibility(
+                                CarFullscreen.revealed,
+                                Modifier.align(Alignment.TopCenter).padding(top = 12.dp),
+                                enter = androidx.compose.animation.slideInVertically { -it },
+                                exit = androidx.compose.animation.slideOutVertically { -it },
+                            ) {
+                                GsButton(onClick = CarFullscreen::exit, modifier = Modifier.height(48.dp)) {
+                                    Icon(MediaIcons.FullscreenExit, contentDescription = null, modifier = Modifier.size(22.dp))
+                                    Spacer(Modifier.width(8.dp))
+                                    Text("Exit full screen", style = MaterialTheme.typography.titleMedium)
+                                }
+                            }
                         }
                     }
-                    // The keyboard takes the nav bar's row instead of squeezing in above it -
-                    // nothing on the nav bar is useful mid-type, and the screen is too small to
-                    // show both.
-                    val keyboardVisible by CarKeyboardVisibility.state
-                    if (!keyboardVisible) CarNavBar(navigator)
                 }
                 // Over everything, nav bar included: a long press on an app, anywhere.
                 AppMenu(navigator, rememberRunningApps())
@@ -284,6 +359,14 @@ fun CarUi() {
     }
 }
 
+internal val NAV_BAR_HEIGHT = 56.dp
+
+/**
+ * How much of the bottom of Home the floating nav bar covers right now: its height while it shows,
+ * zero while it's hidden or when it has a row of its own.
+ */
+internal val LocalNavBarInset = androidx.compose.runtime.compositionLocalOf { 0.dp }
+
 /**
  * A single blocking screen, shown once per install before anything else the car screen can show -
  * Home included. The phone's own setup guide carries the same warning, but a driver who plugs in
@@ -398,512 +481,6 @@ private fun DebugBuildBadge(modifier: Modifier = Modifier) {
     }
 }
 
-/**
- * "Home > Apps > Settings", like a file manager's address bar: hidden at Home itself (nothing to
- * show yet), and grows by one crumb for every screen pushed from there. The back arrow undoes one
- * step; a crumb jumps straight to it, dropping everything after - this is the only on-screen way
- * back at all, since a car touchscreen has no hardware button for it.
- */
-@Composable
-private fun BreadcrumbBar(navigator: CarNavigator) {
-    val trail = navigator.trail
-    if (trail.size <= 1) return
-    Row(
-        Modifier.fillMaxWidth().height(40.dp).padding(start = 2.dp, end = 10.dp),
-        verticalAlignment = Alignment.CenterVertically,
-    ) {
-        GsIconButton(Icons.AutoMirrored.Filled.ArrowBack, "Back", navigator::back, size = 32.dp, iconSize = 20.dp)
-        Spacer(Modifier.width(2.dp))
-        trail.forEachIndexed { index, crumb ->
-            val isLast = index == trail.lastIndex
-            Text(
-                crumb.label,
-                style = MaterialTheme.typography.labelLarge,
-                fontWeight = if (isLast) FontWeight.SemiBold else FontWeight.Normal,
-                color = if (isLast) MaterialTheme.colorScheme.onSurface else MaterialTheme.colorScheme.onSurfaceVariant,
-                maxLines = 1,
-                overflow = TextOverflow.Ellipsis,
-                modifier = if (isLast) Modifier else Modifier
-                    .clip(RoundedCornerShape(6.dp))
-                    .clickable { navigator.jumpTo(index) }
-                    .padding(horizontal = 4.dp, vertical = 2.dp),
-            )
-            if (!isLast) {
-                Text(
-                    "›",
-                    style = MaterialTheme.typography.labelLarge,
-                    color = MaterialTheme.colorScheme.onSurfaceVariant,
-                    modifier = Modifier.padding(horizontal = 2.dp),
-                )
-            }
-        }
-    }
-}
-
-/**
- * Apps and open/pinned shortcuts on the left; now-playing pill against them; clock (tap for
- * calendar and weather), phone battery and the darkness signal on the right. Icon-only: a driver
- * reads a glyph faster than a label, and it keeps the bar short enough to leave the app underneath
- * more room.
- */
-@Composable
-private fun CarNavBar(navigator: CarNavigator) {
-    val battery by CarEnvironment.battery.collectAsState()
-    val now by rememberNow()
-    val weather by Weather.state.collectAsState()
-    val weatherData = (weather as? WeatherState.Ready)?.data
-
-    val pinnedIds by CarSettings.pinnedApps.collectAsState()
-    val entries = rememberAllEntries()
-    val pinnedEntries = remember(entries, pinnedIds) {
-        pinnedIds.mapNotNull { id -> entries.find { it.componentId == id } }
-    }
-    val frame by CarEnvironment.frame.collectAsState()
-    val running = rememberRunningApps()
-
-    Surface(color = MaterialTheme.colorScheme.surfaceContainer) {
-        BoxWithConstraints(Modifier.fillMaxWidth().height(56.dp).padding(horizontal = 10.dp)) {
-            Row(Modifier.fillMaxSize(), verticalAlignment = Alignment.CenterVertically) {
-                // Home and Apps are two different places now, not a toggle on one button - the
-                // breadcrumb trail is how you retrace your steps, but reaching for either of
-                // these two from three screens deep in a media app shouldn't mean reading it
-                // first.
-                NavHomeButton(navigator, entries, running)
-                Spacer(Modifier.width(6.dp))
-                NavItem(MediaIcons.Apps, navigator.current == CarScreen.Apps) { navigator.apps() }
-                Spacer(Modifier.width(6.dp))
-                NavAssistantIcon()
-
-                // Pinned shortcuts, then whatever else is open right now. A pinned app that's also
-                // open stays in its pinned spot, marked with a dot, instead of showing up twice.
-                // The map app lives on the Home button, so it never gets a second icon here.
-                val runningEntries = running.keys
-                    .filter { it !in pinnedIds && running[it] != RunningSlot.NAV }
-                    .mapNotNull { id -> entries.find { it.componentId == id } }
-                val shownPins = pinnedEntries.filter { running[it.componentId] != RunningSlot.NAV }
-                if (shownPins.isNotEmpty() || runningEntries.isNotEmpty()) NavDivider()
-                shownPins.forEach { entry -> NavEntryIcon(entry, running, navigator, frame) }
-                if (shownPins.isNotEmpty() && runningEntries.isNotEmpty()) NavDivider()
-                runningEntries.forEach { entry -> NavEntryIcon(entry, running, navigator, frame) }
-
-                // Next turn first, off the map only; the player shares the space when it fits,
-                // and gives way to the turn when it doesn't.
-                val turn = rememberNextTurn().takeIf { navigator.current != CarScreen.Home }
-                BoxWithConstraints(Modifier.weight(1f).padding(horizontal = 16.dp), contentAlignment = Alignment.Center) {
-                    val roomForBoth = maxWidth >= TURN_AND_PLAYER_MIN_WIDTH
-                    Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(10.dp)) {
-                        turn?.let { NavTurnPill(it) { navigator.home() } }
-                        if (turn == null || roomForBoth) {
-                            NavNowPlaying(navigator, selected = navigator.current == CarScreen.Media, modifier = Modifier.weight(1f, fill = false))
-                        }
-                    }
-                }
-
-                // Weather no longer has its own chip - the temperature alone (no icon, no room
-                // for one) sits where "Night"/"Day" used to, freeing a whole chip's width for the
-                // Home button above.
-                // The clock is also the notifications button: the dashboard lists them under the
-                // calendar and weather, and a dot here marks anything unread.
-                val unread by CarNotifications.unread.collectAsState()
-                NavChip(
-                    navigator.current == CarScreen.Dashboard || navigator.current is CarScreen.Notifications,
-                    { navigator.dashboard() },
-                ) {
-                    if (unread > 0) {
-                        Box(
-                            Modifier
-                                .align(Alignment.TopEnd)
-                                .offset(x = 8.dp, y = (-2).dp)
-                                .size(8.dp)
-                                .clip(CircleShape)
-                                .background(MaterialTheme.colorScheme.primary),
-                        )
-                    }
-                    Column(horizontalAlignment = Alignment.End) {
-                        Text(
-                            DateFormat.getTimeInstance(DateFormat.SHORT).format(Date(now)),
-                            style = MaterialTheme.typography.titleMedium,
-                            fontWeight = FontWeight.SemiBold,
-                        )
-                        Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(3.dp)) {
-                            if (battery.percent >= 0) {
-                                Text(
-                                    "${battery.percent}%",
-                                    style = MaterialTheme.typography.labelMedium,
-                                    color = MaterialTheme.colorScheme.onSurfaceVariant,
-                                )
-                                if (battery.charging) {
-                                    ChargingGlyph(Modifier.size(13.dp))
-                                }
-                            }
-                            weatherData?.let { w ->
-                                Text(
-                                    "  ·  ${w.temp}°",
-                                    style = MaterialTheme.typography.labelMedium,
-                                    color = MaterialTheme.colorScheme.onSurfaceVariant,
-                                )
-                            }
-                        }
-                    }
-                }
-            }
-        }
-    }
-}
-
-/**
- * Home: the map, with the player or lyrics beside it. While a map app runs, the button wears that
- * app's icon and a long press offers to close it, so the app needs no icon of its own on the bar.
- */
-@Composable
-private fun NavHomeButton(navigator: CarNavigator, entries: List<Entry>, running: Map<String, RunningSlot>) {
-    val selected = navigator.current == CarScreen.Home
-    val navId = running.entries.firstOrNull { it.value == RunningSlot.NAV }?.key
-    val navEntry = navId?.let { id -> entries.find { it.componentId == id } }
-    GsIconBox(
-        { navigator.home() },
-        colors = navColors(selected),
-        latched = selected,
-        onLongClick = navId?.let { id -> { navigator.showAppMenu(id) } },
-    ) {
-        val icon = navEntry?.icon
-        if (icon != null) {
-            Box(Modifier.padding(NAV_ITEM_PADDING).size(28.dp), contentAlignment = Alignment.Center) {
-                Image(icon, navEntry.label, Modifier.size(28.dp).clip(RoundedCornerShape(7.dp)))
-            }
-        } else {
-            Icon(
-                ImageVector.vectorResource(R.drawable.navigation_24), contentDescription = "Home",
-                modifier = Modifier.padding(NAV_ITEM_PADDING).size(28.dp),
-            )
-        }
-    }
-}
-
-/** Splits the nav bar's sections: Home and Apps, pinned apps, open apps. */
-@Composable
-private fun NavDivider() {
-    Box(
-        Modifier
-            .padding(horizontal = 10.dp)
-            .width(1.dp)
-            .height(28.dp)
-            .background(MaterialTheme.colorScheme.outlineVariant),
-    )
-}
-
-/**
- * A pinned or open app on the nav bar. Tapping brings it back without reconnecting if it's
- * already open; a long press opens its menu (pin, unpin, close).
- */
-@Composable
-private fun NavEntryIcon(
-    entry: Entry,
-    running: Map<String, RunningSlot>,
-    navigator: CarNavigator,
-    frame: CarEnvironment.Frame,
-) {
-    val id = entry.componentId ?: return
-    val slot = running[id]
-    Box(Modifier.padding(horizontal = 3.dp)) {
-        NavAppIcon(
-            entry,
-            open = slot != null,
-            showing = slot != null && slot.isShowing(navigator.current),
-            onLongClick = { navigator.showAppMenu(id) },
-        ) { openApp(entry, slot, navigator, frame) }
-    }
-}
-
-/** One open or pinned app's icon on the nav bar - the same fixed size and shape either way. */
-@Composable
-private fun NavAppIcon(
-    entry: Entry,
-    open: Boolean,
-    showing: Boolean,
-    onLongClick: () -> Unit,
-    onClick: () -> Unit,
-) {
-    val scheme = MaterialTheme.colorScheme
-    GsIconBox(
-        onClick,
-        Modifier.size(44.dp),
-        colors = if (showing) GsColors(scheme.secondaryContainer, scheme.onSecondaryContainer)
-        else GsColors(scheme.surfaceVariant, scheme.onSurfaceVariant),
-        latched = showing,
-        onLongClick = onLongClick,
-    ) {
-        entry.icon?.let { Image(it, entry.label, Modifier.size(30.dp).clip(RoundedCornerShape(8.dp))) }
-        entry.builtIn?.let { Icon(it.glyph, entry.label, Modifier.size(26.dp)) }
-        // Only running apps get the line along the bottom edge, the usual taskbar mark for it.
-        if (open) {
-            Box(
-                Modifier
-                    .align(Alignment.BottomCenter)
-                    .padding(bottom = 2.dp)
-                    .size(width = 12.dp, height = 3.dp)
-                    .clip(RoundedCornerShape(50))
-                    .background(scheme.primary),
-            )
-        }
-    }
-}
-
-/** A tappable group in the bar that stays highlighted while its screen is open, like [NavItem]. */
-@Composable
-private fun NavChip(selected: Boolean, onClick: () -> Unit, content: @Composable BoxScope.() -> Unit) {
-    GsIconBox(onClick, colors = navColors(selected), latched = selected) {
-        Box(Modifier.padding(horizontal = 10.dp, vertical = 2.dp)) { content() }
-    }
-}
-
-/** Every nav bar item is raised, so it reads as pressable; the current screen's takes the accent colour. */
-@Composable
-private fun navColors(selected: Boolean): GsColors {
-    val s = MaterialTheme.colorScheme
-    return if (selected) GsColors(s.secondaryContainer, s.onSecondaryContainer)
-    else GsColors(s.surfaceContainerHighest, s.onSurface)
-}
-
-/**
- * Between Apps and whatever's actually open, not with the clock/battery group on the right - a
- * driver reaches for it right after deciding "not a tap for this", same gesture family as the
- * two buttons beside it.
- */
-@Composable
-private fun NavAssistantIcon() {
-    val state by CarAssistant.state.collectAsState()
-    val active = state.phase != CarAssistant.Phase.IDLE
-    GsIconBox({ CarAssistant.start() }, colors = navColors(active), latched = active) {
-        MicGlyph(Modifier.padding(NAV_ITEM_PADDING).size(28.dp))
-    }
-}
-
-/** Inner padding of every icon on the nav bar, leaving each button room inside the 56dp bar. */
-private val NAV_ITEM_PADDING = 8.dp
-
-@Composable
-private fun NavItem(icon: ImageVector, selected: Boolean, onClick: () -> Unit) {
-    GsIconBox(onClick, colors = navColors(selected), latched = selected) {
-        Icon(icon, contentDescription = null, modifier = Modifier.padding(NAV_ITEM_PADDING).size(28.dp))
-    }
-}
-
-/** Wall-clock time, ticking on the minute: no reason to redraw (and re-encode) more often. */
-@Composable
-internal fun rememberNow(): State<Long> = produceState(System.currentTimeMillis()) {
-    while (true) {
-        value = System.currentTimeMillis()
-        delay(60_000 - value % 60_000)
-    }
-}
-
-/** How long the pill shows a new song's title before settling to just the controls. */
-private const val TITLE_SHOWN_MS = 3_000L
-
-/** Below this, the nav bar's middle only has room for the turn, not the player beside it. */
-private val TURN_AND_PLAYER_MIN_WIDTH = 520.dp
-
-/** The next manoeuvre, as the running nav app last described it. */
-private class NextTurn(val icon: CarIcon?, val distance: String, val road: String)
-
-/**
- * Read straight off the nav app's own template: a navigation app keeps sending its routing card
- * while it's running, whether or not the map is the screen being shown.
- */
-@Composable
-private fun rememberNextTurn(): NextTurn? {
-    val status by CarServices.nav.status.collectAsState()
-    val template by CarServices.nav.template.collectAsState()
-    // Read so a change of units redraws the distance straight away, not at the next update.
-    CarSettings.units.collectAsState().value
-    if (status.phase != CarAppConnection.Phase.RUNNING) return null
-    val routing = (template as? NavigationTemplate)?.navigationInfo as? RoutingInfo ?: return null
-    if (routing.isLoading) return null
-    val step = routing.currentStep ?: return null
-    return NextTurn(
-        icon = step.maneuver?.icon,
-        distance = routing.currentDistance.display(),
-        road = step.road.text().ifEmpty { step.cue.text() },
-    )
-}
-
-/** The next turn in the nav bar: arrow, how far, onto what. Tapping goes back to the map. */
-@Composable
-private fun NavTurnPill(turn: NextTurn, onClick: () -> Unit) {
-    // Same finish as every other button on the bar, in the accent colour; the text runs a step
-    // bigger than anything else there, since it's the one thing worth a glance mid-drive.
-    GsIconBox(
-        onClick,
-        Modifier.widthIn(max = 340.dp).height(44.dp),
-        colors = gsColors(GsTone.Primary),
-    ) {
-        Row(
-            Modifier.padding(NAV_ITEM_PADDING),
-            verticalAlignment = Alignment.CenterVertically,
-            horizontalArrangement = Arrangement.spacedBy(8.dp),
-        ) {
-            CarGlyph(turn.icon, Modifier.size(28.dp))
-            if (turn.distance.isNotEmpty()) {
-                Text(turn.distance, style = MaterialTheme.typography.titleLarge, fontWeight = FontWeight.Bold, maxLines = 1)
-            }
-            if (turn.road.isNotEmpty()) {
-                Text(
-                    turn.road,
-                    style = MaterialTheme.typography.titleMedium,
-                    fontWeight = FontWeight.SemiBold,
-                    maxLines = 1,
-                    overflow = TextOverflow.Ellipsis,
-                )
-            }
-        }
-    }
-}
-
-/** "Title - Artist" on one line. The text itself cuts it off, and only where the pill runs out of room. */
-private fun nowPlayingLabel(title: String, artist: String): String =
-    listOf(title.trim(), artist.trim()).filter { it.isNotEmpty() }.joinToString(" - ")
-        .ifEmpty { "Nothing playing" }
-
-/**
- * The player in the nav bar, on every screen. Art and title open the full media screen;
- * play/pause and skip work right here. The dock button moves the player into the column beside
- * the map on Home (see [CarHome]), and the pill steps aside there while it's docked - unless the
- * column is showing lyrics instead, when the pill stays and its dock button swaps them back.
- */
-@Composable
-private fun NavNowPlaying(navigator: CarNavigator, selected: Boolean, modifier: Modifier = Modifier) {
-    val media = CarServices.media
-    val phase by media.phase.collectAsState()
-    val now by media.now.collectAsState()
-    if (phase != CarMedia.Phase.READY || !now.isActive) return
-    // Docked beside the map, the player is already on screen - the pill steps aside for it.
-    if (navigator.sidePanel == SidePanel.CONTROLS && navigator.current == CarScreen.Home) return
-    // The media screen is the full player already; the pill would only repeat its controls.
-    if (navigator.current == CarScreen.Media) return
-    val context = LocalContext.current
-    val art by produceState(now.art, now.art, now.artUri) { value = now.art ?: MediaArt.load(context, now.artUri) }
-    val position by produceState(now.currentPosition(), now) {
-        while (true) {
-            value = now.currentPosition()
-            if (!now.playing) break
-            delay(1000)
-        }
-    }
-
-    // A new song announces itself: title, play/pause and dock for a few seconds, then the title
-    // goes and the pill settles to just the controls - unless the driver keeps the title up.
-    val keepTitle by CarSettings.playerTitle.collectAsState()
-    var announcing by remember { mutableStateOf(true) }
-    LaunchedEffect(now.title, now.artist) {
-        announcing = true
-        delay(TITLE_SHOWN_MS)
-        announcing = false
-    }
-    val showTitle = keepTitle || announcing
-
-    val scheme = MaterialTheme.colorScheme
-    val onPill = if (selected) scheme.onPrimaryContainer else scheme.onSecondaryContainer
-    Surface(
-        modifier = modifier
-            .animateContentSize()
-            // With the title up, all the room the bar has, so as much of it shows as can.
-            .then(if (showTitle) Modifier.fillMaxWidth() else Modifier)
-            .height(44.dp),
-        shape = RoundedCornerShape(14.dp),
-        color = if (selected) scheme.primaryContainer else scheme.secondaryContainer,
-        contentColor = onPill,
-    ) {
-        Box {
-            Row(
-                Modifier.fillMaxHeight().padding(horizontal = 4.dp),
-                verticalAlignment = Alignment.CenterVertically,
-                horizontalArrangement = Arrangement.spacedBy(6.dp),
-            ) {
-                // Art (and the title while it shows) opens the full media screen.
-                Row(
-                    Modifier
-                        .then(if (showTitle) Modifier.weight(1f) else Modifier)
-                        .fillMaxHeight()
-                        .clip(RoundedCornerShape(10.dp))
-                        .clickable { navigator.media() },
-                    verticalAlignment = Alignment.CenterVertically,
-                    horizontalArrangement = Arrangement.spacedBy(8.dp),
-                ) {
-                    Box(Modifier.size(34.dp).clip(RoundedCornerShape(8.dp)).background(scheme.surfaceVariant)) {
-                        art?.let { Image(it.asImageBitmap(), null, Modifier.fillMaxSize(), contentScale = ContentScale.Crop) }
-                    }
-                    if (showTitle) {
-                        Text(
-                            nowPlayingLabel(now.title, now.artist),
-                            style = MaterialTheme.typography.titleSmall,
-                            fontWeight = FontWeight.SemiBold,
-                            maxLines = 1,
-                            overflow = TextOverflow.Ellipsis,
-                        )
-                    }
-                }
-                if (!showTitle) {
-                    GsIconButton(
-                        MediaIcons.Previous, "Previous", media::previous,
-                        enabled = now.canDo(PlaybackState.ACTION_SKIP_TO_PREVIOUS), size = 36.dp, iconSize = 22.dp,
-                    )
-                }
-                GsIconButton(
-                    if (now.playing) MediaIcons.Pause else Icons.Filled.PlayArrow,
-                    if (now.playing) "Pause" else "Play",
-                    media::togglePlay,
-                    tone = GsTone.Primary, size = 36.dp, iconSize = 22.dp,
-                )
-                if (!showTitle) {
-                    GsIconButton(
-                        MediaIcons.Next, "Next", media::next,
-                        enabled = now.canDo(PlaybackState.ACTION_SKIP_TO_NEXT), size = 36.dp, iconSize = 22.dp,
-                    )
-                }
-                GsIconButton(
-                    MediaIcons.DockRight, "Move the player beside the map", navigator::togglePlayerDock,
-                    size = 36.dp, iconSize = 22.dp,
-                )
-            }
-            if (now.durationMs > 0) {
-                // matchParentSize, so the line follows the pill's width rather than widening it.
-                Box(Modifier.matchParentSize(), contentAlignment = Alignment.BottomStart) {
-                    Box(
-                        Modifier
-                            .fillMaxWidth((position.toFloat() / now.durationMs).coerceIn(0f, 1f))
-                            .height(2.dp)
-                            .background(onPill.copy(alpha = 0.7f)),
-                    )
-                }
-            }
-        }
-    }
-}
-
-/**
- * A filled lightning bolt, next to the battery percentage instead of the word "charging" - the
- * core Material icon set this project ships (no extended pack, to keep the app small) has no
- * bolt, so this is drawn rather than a vector asset.
- */
-@Composable
-private fun ChargingGlyph(modifier: Modifier = Modifier, tint: Color = MaterialTheme.colorScheme.onSurfaceVariant) {
-    androidx.compose.foundation.Canvas(modifier) {
-        val w = size.width
-        val h = size.height
-        val bolt = androidx.compose.ui.graphics.Path().apply {
-            moveTo(w * 0.58f, 0f)
-            lineTo(w * 0.12f, h * 0.58f)
-            lineTo(w * 0.46f, h * 0.58f)
-            lineTo(w * 0.42f, h)
-            lineTo(w * 0.88f, h * 0.40f)
-            lineTo(w * 0.54f, h * 0.40f)
-            close()
-        }
-        drawPath(bolt, tint)
-    }
-}
-
 /** Stands in for the phone's vibration motor on the car screen: does nothing. */
 private object NoHaptics : HapticFeedback {
     override fun performHapticFeedback(hapticFeedbackType: HapticFeedbackType) {}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/ClusterNav.kt

@@ -24,23 +24,36 @@ import app.seb3thehacker.gearslip.Protobuf
  */
 class ClusterNav(
     val channelId: Int,
+    minimumIntervalMs: Long = 0,
     private val sendOnChannel: (messageId: Int, body: ByteArray) -> Unit,
 ) {
+    private val updateIntervalMs = maxOf(TICK_MS, minimumIntervalMs)
     @Volatile private var running = false
+    private var worker: Thread? = null
+    private var updatesRequested = true
     private var sentStatus = -1
     private var sentTurn: String? = null
     private var sentDistance: String? = null
 
+    @Synchronized
     fun onMessage(messageId: Int, body: ByteArray) {
         when (messageId) {
             MSG_CHANNEL_OPEN_RESPONSE -> {
-                val status = Protobuf.readInt32Field(body, 1) ?: 0
+                val status = Protobuf.readInt32Field(body, 1)
                 GearslipLog.i("cluster: <- ChannelOpenResponse: status=$status")
                 if (status == 0) start()
             }
-            // The car saying when it wants turns. Sending all along is harmless, so these are only logged.
-            MSG_START -> GearslipLog.i("cluster: <- start")
-            MSG_STOP -> GearslipLog.i("cluster: <- stop")
+            MSG_START -> {
+                updatesRequested = true
+                sentStatus = -1
+                sentTurn = null
+                sentDistance = null
+                GearslipLog.i("cluster: <- start")
+            }
+            MSG_STOP -> {
+                updatesRequested = false
+                GearslipLog.i("cluster: <- stop")
+            }
             else -> GearslipLog.i("cluster: <- unhandled message id=$messageId (${body.size} bytes)")
         }
     }
@@ -48,19 +61,28 @@ class ClusterNav(
     private fun start() {
         if (running) return
         running = true
-        Thread({
+        worker = Thread({
             while (running) {
                 runCatching { tick() }.onFailure { GearslipLog.w("cluster: ${it.message}") }
-                Thread.sleep(TICK_MS)
+                try {
+                    Thread.sleep(updateIntervalMs)
+                } catch (_: InterruptedException) {
+                    return@Thread
+                }
             }
-        }, "gearslip-cluster").start()
+        }, "gearslip-cluster").also { it.start() }
     }
 
+    @Synchronized
     fun stop() {
         running = false
+        worker?.interrupt()
+        worker = null
     }
 
+    @Synchronized
     private fun tick() {
+        if (!running || !updatesRequested) return
         val turn = NavTurn.current()
         val status = when {
             turn == null -> STATUS_INACTIVE
@@ -82,7 +104,7 @@ class ClusterNav(
         val maneuver = step.maneuver
         val (event, side) = maneuver?.let { eventFor(it.type) } ?: (EVENT_UNKNOWN to SIDE_UNSPECIFIED)
         val road = step.road.text().ifBlank { step.cue.text() }
-        val key = "$road|$event|$side|${maneuver?.roundaboutExitNumber}"
+        val key = "$road|$event|$side|${maneuver?.roundaboutExitNumber}|${maneuver?.roundaboutExitAngle}"
         if (key == sentTurn) return
         sentTurn = key
         var body = Protobuf.stringField(1, road) +

gearslip/src/main/java/app/seb3thehacker/gearslip/car/DirectionsVoice.kt

@@ -27,7 +27,8 @@ import kotlin.math.roundToInt
  * same turn the instrument cluster gets ([NavTurn]) and says it itself: once when the turn comes
  * up, again a kilometre or so out on a long stretch, and once more just before it. The words are
  * rendered with the phone's text-to-speech to a file, never played on the phone, and streamed to
- * the car, which ducks the music under them the way it does for real Android Auto.
+ * the car, which ducks the music under them the way it does for real Android Auto. When the music
+ * isn't Gearslip's, each announcement first asks the car for its speakers, as Android Auto does.
  *
  * Nothing spoken is logged: road names are where the driver is going.
  */
@@ -42,7 +43,10 @@ object DirectionsVoice {
 
     @Volatile private var link: AudioLink? = null
     @Volatile private var running = false
-    private val speaker = Executors.newSingleThreadExecutor { Thread(it, "gearslip-directions").apply { isDaemon = true } }
+    @Volatile private var musicIsOurs: () -> Boolean = { false }
+    private val speaker = Executors.newSingleThreadScheduledExecutor { Thread(it, "gearslip-directions").apply { isDaemon = true } }
+    /** Counts announcements, so a hand-back scheduled after one is dropped if another has begun. */
+    private var spoken = 0
     @Volatile private var latest = 0
 
     private var turnKey: String? = null
@@ -62,8 +66,9 @@ object DirectionsVoice {
     }
 
     /** The car opened its directions sink: start following the map app's turns. */
-    fun attach(link: AudioLink) {
+    fun attach(link: AudioLink, musicIsOurs: () -> Boolean) {
         this.link = link
+        this.musicIsOurs = musicIsOurs
         GearslipLog.i("guidance: the car offered a directions sink at ${link.sampleRate}Hz x${link.channels}")
         if (running) return
         running = true
@@ -82,16 +87,26 @@ object DirectionsVoice {
         running = false
     }
 
+    /** Why the last turn wasn't spoken, so the log says it once rather than every tick. */
+    private var silentBecause: String? = null
+
+    private fun quiet(reason: String) {
+        if (silentBecause == reason) return
+        silentBecause = reason
+        GearslipLog.i("guidance: not speaking - $reason")
+    }
+
     private fun tick() {
-        if (!CarSettings.speakDirections.value) return
         val turn = NavTurn.current()
         if (turn == null) {
             turnKey = null
             return
         }
-        if (turn.rerouting) return
+        if (!CarSettings.speakDirections.value) return quiet("Spoken directions is off in the car's Settings")
+        if (turn.rerouting) return quiet("the map app is rerouting")
         val step = turn.step
-        val instruction = instruction(step) ?: return
+        val instruction = instruction(step) ?: return quiet("the map app gave this turn no words")
+        silentBecause = null
         val meters = turn.distance?.let(NavTurn::toMeters)
         val close = (turn.seconds != null && turn.seconds <= NEAR_SECONDS) || (meters != null && meters <= NEAR_METERS)
 
@@ -223,7 +238,16 @@ object DirectionsVoice {
             GearslipLog.w("guidance: text-to-speech gave audio Gearslip can't read")
             return
         }
-        stream(sink, pcm)
+        // Logged before speaking too, so a car that dies mid-announcement shows what it was doing.
+        GearslipLog.i("guidance: speaking a turn")
+        // Held through back-to-back prompts rather than asked for and given back each time.
+        if (!musicIsOurs()) sink.askForSpeakers()
+        val turn = ++spoken
+        try {
+            stream(sink, pcm)
+        } finally {
+            speaker.schedule({ if (turn == spoken) sink.handBackSpeakers() }, HOLD_MS, TimeUnit.MILLISECONDS)
+        }
         GearslipLog.i("guidance: spoke a turn (${pcm.size / (2 * sink.channels) * 1000 / sink.sampleRate} ms)")
     }
 
@@ -321,6 +345,7 @@ object DirectionsVoice {
     private const val PREPARE_FROM_METERS = 2_500
     private const val PREPARE_AT_METERS = 1_000
     private const val LEAD_MS = 100L
+    private const val HOLD_MS = 2_000L
     private const val SYNTH_TIMEOUT_S = 10L
     private val ORDINALS = listOf("first", "second", "third", "fourth", "fifth", "sixth", "seventh", "eighth")
 }

gearslip/src/main/java/app/seb3thehacker/gearslip/car/MapControlsWake.kt

@@ -11,27 +11,35 @@ import android.os.SystemClock
  *
  * They fade out after [IDLE_MS] with no touch anywhere on the car screen, to leave the map clear,
  * and any touch brings them back. [touch] is called for every pointer event and is cheap: it only
- * writes state when the buttons were actually hidden.
+ * writes state when the buttons were actually hidden. The nav bar, when set to hide, goes the
+ * same way but waits longer ([NAV_BAR_IDLE_MS]).
  */
 class MapControlsWake {
 
     var awake by mutableStateOf(true)
         private set
 
+    var navBarAwake by mutableStateOf(true)
+        private set
+
     private var lastTouch = SystemClock.uptimeMillis()
 
     fun touch() {
         lastTouch = SystemClock.uptimeMillis()
         if (!awake) awake = true
+        if (!navBarAwake) navBarAwake = true
     }
 
     /** Called on a timer; hides the buttons once nothing has touched the screen for [IDLE_MS]. */
     fun tick() {
-        if (awake && SystemClock.uptimeMillis() - lastTouch >= IDLE_MS) awake = false
+        val idle = SystemClock.uptimeMillis() - lastTouch
+        if (awake && idle >= IDLE_MS) awake = false
+        if (navBarAwake && idle >= NAV_BAR_IDLE_MS) navBarAwake = false
     }
 
     companion object {
         const val IDLE_MS = 4_000L
+        const val NAV_BAR_IDLE_MS = 8_000L
     }
 }
 

gearslip/src/main/java/app/seb3thehacker/gearslip/car/MediaBrowse.kt

@@ -0,0 +1,232 @@
+package app.seb3thehacker.gearslip.car
+
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import app.seb3thehacker.gearslip.car.theme.*
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.background
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.foundation.layout.Arrangement
+import android.provider.Settings
+import android.content.Intent
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.BoxWithConstraints
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.lazy.itemsIndexed
+import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.KeyboardArrowRight
+import androidx.compose.material.icons.filled.ArrowBack
+import androidx.compose.material.icons.filled.PlayArrow
+import androidx.compose.material.icons.filled.Search
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableLongStateOf
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.produceState
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.PathFillType
+import androidx.compose.ui.graphics.SolidColor
+import androidx.compose.foundation.layout.widthIn
+import androidx.compose.ui.graphics.asImageBitmap
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.graphics.vector.addPathNodes
+import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import app.seb3thehacker.gearslip.media.CarMedia
+import app.seb3thehacker.gearslip.media.MediaApp
+import app.seb3thehacker.gearslip.media.MediaArt
+import app.seb3thehacker.gearslip.media.LyricsResult
+import app.seb3thehacker.gearslip.media.Lyrics
+import app.seb3thehacker.gearslip.media.MediaEntry
+import app.seb3thehacker.gearslip.media.NowPlaying
+import app.seb3thehacker.gearslip.media.QueueTrack
+import android.media.session.PlaybackState
+import kotlinx.coroutines.delay
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.PaddingValues
+
+// The media screen's browse list, up-next queue, rows and icons. Split out of MediaScreen.kt.
+
+@Composable
+internal fun BrowsePanel(browse: app.seb3thehacker.gearslip.media.BrowseState, media: CarMedia, appLabel: String, modifier: Modifier) {
+    Column(modifier) {
+        // At the library root there's no trail and nowhere to go up to, so there's nothing this
+        // row could say that the app's name in the top-left corner hasn't already - showing it
+        // again here (as "Browse", or as the app's own name) was just the same label twice.
+        if (media.canGoUp || browse.trail.isNotEmpty()) {
+            Row(verticalAlignment = Alignment.CenterVertically) {
+                if (media.canGoUp) {
+                    GsIconButton(Icons.Filled.ArrowBack, "Up", media::up)
+                }
+                browse.trail.lastOrNull()?.let {
+                    Text(
+                        it,
+                        style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold,
+                        maxLines = 1, overflow = TextOverflow.Ellipsis,
+                    )
+                }
+            }
+        }
+        when {
+            browse.loading -> Notice("Loading…", null)
+            browse.unavailable -> Notice(
+                "$appLabel keeps its library to itself.",
+                "Start music in the app on your phone. Play, pause, skip and seek work from here.",
+            )
+            browse.failed -> Notice("Could not load this list.", null)
+            browse.entries.isEmpty() -> Notice("Nothing here.", null)
+            else -> LazyColumn(Modifier.fillMaxSize(), verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                items(browse.entries, key = { it.id }) { entry -> EntryRow(entry, media) }
+            }
+        }
+    }
+}
+
+// --- up next -----------------------------------------------------------------------------------
+
+/**
+ * Whatever the app has queued up, starting right after the track that's playing now - not the
+ * whole queue from the top, which would just repeat what the player beside it already shows. Apps
+ * that never publish a queue (many don't) show an empty notice rather than a permanently blank tab.
+ */
+@Composable
+internal fun QueuePanel(queue: List<QueueTrack>, now: NowPlaying, media: CarMedia, modifier: Modifier) {
+    val upNext = remember(queue, now.activeQueueItemId) {
+        val current = queue.indexOfFirst { it.queueId == now.activeQueueItemId }
+        if (current >= 0) queue.drop(current + 1) else queue
+    }
+    Column(modifier) {
+        if (upNext.isEmpty()) {
+            Notice(
+                "Nothing queued.",
+                "${if (now.title.isEmpty()) "Nothing playing" else "Only what's already playing"} - " +
+                    "not every app tells Gearslip what comes next.",
+            )
+        } else {
+            LazyColumn(Modifier.fillMaxSize(), verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                items(upNext, key = { it.queueId }) { track -> QueueRow(track, media) }
+            }
+        }
+    }
+}
+
+@Composable
+private fun QueueRow(track: QueueTrack, media: CarMedia) {
+    val context = LocalContext.current
+    val icon by produceState(track.iconBitmap, track.iconUri) {
+        value = track.iconBitmap ?: MediaArt.load(context, track.iconUri)
+    }
+    Surface(
+        onClick = { media.playQueueItem(track) },
+        shape = MaterialTheme.shapes.large,
+        color = MaterialTheme.colorScheme.surfaceVariant,
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        Row(Modifier.padding(10.dp), verticalAlignment = Alignment.CenterVertically) {
+            RowArt(icon, MediaIcons.MusicNote)
+            Column(Modifier.weight(1f).padding(horizontal = 12.dp)) {
+                Text(track.title, style = MaterialTheme.typography.titleSmall, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                if (track.subtitle.isNotEmpty()) {
+                    Text(track.subtitle, style = MaterialTheme.typography.bodySmall, color = MaterialTheme.colorScheme.onSurfaceVariant, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                }
+            }
+            Icon(Icons.Filled.PlayArrow, "Play", tint = MaterialTheme.colorScheme.onSurfaceVariant)
+        }
+    }
+}
+
+@Composable
+internal fun EntryRow(entry: MediaEntry, media: CarMedia, onClick: () -> Unit = { media.select(entry) }) {
+    val context = LocalContext.current
+    val icon by produceState(entry.iconBitmap, entry.iconUri) {
+        value = entry.iconBitmap ?: MediaArt.load(context, entry.iconUri)
+    }
+    Surface(
+        onClick = onClick,
+        shape = MaterialTheme.shapes.large,
+        color = MaterialTheme.colorScheme.surfaceVariant,
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        Row(Modifier.padding(10.dp), verticalAlignment = Alignment.CenterVertically) {
+            RowArt(icon, if (entry.browsable) MediaIcons.Folder else MediaIcons.MusicNote)
+            Column(Modifier.weight(1f).padding(horizontal = 12.dp)) {
+                Text(entry.title, style = MaterialTheme.typography.titleSmall, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                if (entry.subtitle.isNotEmpty()) {
+                    Text(entry.subtitle, style = MaterialTheme.typography.bodySmall, color = MaterialTheme.colorScheme.onSurfaceVariant, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                }
+            }
+            if (entry.browsable && entry.playable) {
+                GsIconButton(Icons.Filled.PlayArrow, "Play", { media.playAll(entry) })
+            }
+            if (entry.browsable) Icon(Icons.AutoMirrored.Filled.KeyboardArrowRight, null)
+        }
+    }
+}
+
+/** A row's artwork, or a folder or note in its place when the app sends none. */
+@Composable
+private fun RowArt(icon: android.graphics.Bitmap?, fallback: ImageVector) {
+    Box(
+        Modifier.size(62.dp).clip(MaterialTheme.shapes.medium).background(MaterialTheme.colorScheme.surfaceContainerHigh),
+        contentAlignment = Alignment.Center,
+    ) {
+        if (icon != null) Image(icon.asImageBitmap(), null, Modifier.fillMaxSize(), contentScale = ContentScale.Crop)
+        else Icon(fallback, null, tint = MaterialTheme.colorScheme.onSurfaceVariant, modifier = Modifier.size(30.dp))
+    }
+}
+
+/** Material's transport icons, from their published path data (they live in the extended set). */
+internal object MediaIcons {
+    val MusicNote = icon("MusicNote", "M12,3v10.55c-0.59,-0.34 -1.27,-0.55 -2,-0.55 -2.21,0 -4,1.79 -4,4s1.79,4 4,4 4,-1.79 4,-4V7h4V3h-6z")
+    val Folder = icon("Folder", "M10,4H4c-1.1,0 -1.99,0.9 -1.99,2L2,18c0,1.1 0.9,2 2,2h16c1.1,0 2,-0.9 2,-2V8c0,-1.1 -0.9,-2 -2,-2h-8l-2,-2z")
+    val Pause = icon("Pause", "M6,19h4L10,5L6,5v14zM14,5v14h4L18,5h-4z")
+    val Next = icon("SkipNext", "M6,18l8.5,-6L6,6v12zM16,6v12h2V6h-2z")
+    /** The 3x3 app grid; not in material-icons-core. */
+    val Apps = icon("Apps", "M4,8h4L8,4L4,4v4zM10,20h4v-4h-4v4zM4,20h4v-4L4,16v4zM4,14h4v-4L4,10v4zM10,14h4v-4h-4v4zM16,4v4h4L20,4h-4zM10,8h4L14,4h-4v4zM16,14h4v-4h-4v4zM16,20h4v-4h-4v4z")
+    val Previous = icon("SkipPrevious", "M6,6h2v12L6,18zM9.5,12l8.5,6V6z")
+    val Equalizer = icon("Equalizer", "M10,20h4L14,4h-4v16zM4,20h4v-8L4,12v8zM16,9v11h4L20,9h-4z")
+    val Shuffle = icon("Shuffle", "M10.59,9.17L5.41,4 4,5.41l5.17,5.17 1.42,-1.41zM14.5,4l2.04,2.04L4,18.59 5.41,20 17.96,7.46 20,9.5L20,4h-5.5zM14.83,13.41l-1.41,1.41 3.13,3.13L14.5,20L20,20v-5.5l-2.04,2.04 -3.13,-3.13z")
+    val Repeat = icon("Repeat", "M7,7h10v3l4,-4 -4,-4v3L5,5v6h2L7,7zM17,17L7,17v-3l-4,4 4,4v-3h12v-6h-2v4z")
+    val RepeatOne = icon("RepeatOne", "M7,7h10v3l4,-4 -4,-4v3L5,5v6h2L7,7zM17,17L7,17v-3l-4,4 4,4v-3h12v-6h-2v4zM13,15L13,9h-1l-2,1v1h1.5v4L13,15z")
+    /** A screen with a filled right-hand panel: "put the player beside the map". */
+    val DockRight = icon("DockRight", "M2,4h20v16H2zM4,6h10v12H4z", PathFillType.EvenOdd)
+    val Fullscreen = icon("Fullscreen", "M7,14L5,14v5h5v-2L7,17v-3zM5,10h2L7,7h3L10,5L5,5v5zM17,17h-3v2h5v-5h-2v3zM14,5v2h3v3h2L19,5h-5z")
+    val FullscreenExit = icon("FullscreenExit", "M5,16h3v3h2v-5L5,14v2zM8,8L5,8v2h5L10,5L8,5v3zM14,19h2v-3h3v-2h-5v5zM16,8L16,5h-2v5h5L19,8h-3z")
+
+    val CallEnd = icon("CallEnd", "M12,9c-1.6,0 -3.15,0.25 -4.6,0.72v3.1c0,0.39 -0.23,0.74 -0.56,0.9 -0.98,0.49 -1.87,1.12 -2.66,1.85 -0.18,0.18 -0.43,0.28 -0.7,0.28 -0.28,0 -0.53,-0.11 -0.71,-0.29L0.29,13.08c-0.18,-0.17 -0.29,-0.42 -0.29,-0.7 0,-0.28 0.11,-0.53 0.29,-0.71C3.34,8.78 7.46,7 12,7s8.66,1.78 11.71,4.67c0.18,0.18 0.29,0.43 0.29,0.71 0,0.28 -0.11,0.53 -0.29,0.71l-2.48,2.48c-0.18,0.18 -0.43,0.29 -0.71,0.29 -0.27,0 -0.52,-0.11 -0.7,-0.28 -0.79,-0.74 -1.69,-1.36 -2.67,-1.85 -0.33,-0.16 -0.56,-0.5 -0.56,-0.9v-3.1C15.15,9.25 13.6,9 12,9z")
+    val Mic = icon("Mic", "M12,14c1.66,0 2.99,-1.34 2.99,-3L15,5c0,-1.66 -1.34,-3 -3,-3S9,3.34 9,5v6c0,1.66 1.34,3 3,3zM17.3,11c0,3 -2.54,5.1 -5.3,5.1S6.7,14 6.7,11L5,11c0,3.41 2.72,6.23 6,6.72L11,21h2v-3.28c3.28,-0.48 6,-3.3 6,-6.72h-1.7z")
+    val MicOff = icon("MicOff", "M19,11h-1.7c0,0.74 -0.16,1.43 -0.43,2.05l1.23,1.23c0.56,-0.98 0.9,-2.09 0.9,-3.28zM14.98,11.17c0,-0.06 0.02,-0.11 0.02,-0.17L15,5c0,-1.66 -1.34,-3 -3,-3S9,3.34 9,5v0.18l5.98,5.99zM4.27,3L3,4.27l6.01,6.01L9,11c0,1.66 1.33,3 2.99,3 0.22,0 0.44,-0.03 0.65,-0.08l1.66,1.66c-0.71,0.33 -1.5,0.52 -2.31,0.52 -2.76,0 -5.3,-2.1 -5.3,-5.1L5,11c0,3.41 2.72,6.23 6,6.72L11,21h2v-3.28c0.91,-0.13 1.77,-0.45 2.54,-0.9L19.73,21 21,19.73 4.27,3z")
+
+    private fun icon(name: String, path: String, fillType: PathFillType = PathFillType.NonZero) = ImageVector.Builder(
+        name, 24.dp, 24.dp, 24f, 24f,
+    ).addPath(addPathNodes(path), pathFillType = fillType, fill = SolidColor(androidx.compose.ui.graphics.Color.Black)).build()
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/MediaScreen.kt

@@ -93,6 +93,7 @@ fun MediaScreen(app: MediaApp, onExit: () -> Unit) {
 
     // The connection outlives this screen: the home screen's player is the same one.
     LaunchedEffect(app) { CarServices.openMedia(app) }
+    androidx.compose.runtime.DisposableEffect(Unit) { onDispose { CarServices.mediaScreenClosed() } }
 
     val art = rememberArt(now)
 
@@ -444,7 +445,7 @@ private sealed interface LyricsState {
 }
 
 @Composable
-private fun Notice(title: String, detail: String?, action: Pair<String, () -> Unit>? = null) {
+internal fun Notice(title: String, detail: String?, action: Pair<String, () -> Unit>? = null) {
     Column(
         Modifier.fillMaxSize().padding(horizontal = 24.dp),
         verticalArrangement = Arrangement.Center,
@@ -491,7 +492,14 @@ private fun CoverArt(art: android.graphics.Bitmap?, modifier: Modifier) {
             shadowElevation = 6.dp,
             modifier = Modifier.size(minOf(maxWidth, maxHeight)),
         ) {
-            art?.let { Image(it.asImageBitmap(), null, Modifier.fillMaxSize(), contentScale = ContentScale.Crop) }
+            if (art != null) {
+                Image(art.asImageBitmap(), null, Modifier.fillMaxSize(), contentScale = ContentScale.Crop)
+            } else {
+                // No cover (or nothing playing): a note, so the square reads as a cover, not a hole.
+                Box(contentAlignment = Alignment.Center) {
+                    Icon(MediaIcons.MusicNote, null, tint = MaterialTheme.colorScheme.onSurfaceVariant, modifier = Modifier.fillMaxSize(0.35f))
+                }
+            }
         }
     }
 }
@@ -518,6 +526,12 @@ private fun NowPlayingControls(now: NowPlaying, media: CarMedia, modifier: Modif
                 maxLines = 1, overflow = TextOverflow.Ellipsis,
             )
             now.error?.let { Text(it, style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.error, maxLines = 2) }
+            if (now.title.isEmpty() && now.error == null) {
+                Text(
+                    "Press play to pick up where you left off, or find something in Browse.",
+                    style = MaterialTheme.typography.titleMedium, color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+            }
         }
         PlayerProgress(now, media, Modifier.fillMaxWidth())
         TransportRow(now, media, skip = 60.dp, modifier = Modifier.fillMaxWidth())
@@ -555,141 +569,3 @@ private fun CompactPlayer(now: NowPlaying, media: CarMedia, modifier: Modifier)
 
 // --- browsing --------------------------------------------------------------------------------
 
-@Composable
-private fun BrowsePanel(browse: app.seb3thehacker.gearslip.media.BrowseState, media: CarMedia, appLabel: String, modifier: Modifier) {
-    Column(modifier) {
-        // At the library root there's no trail and nowhere to go up to, so there's nothing this
-        // row could say that the app's name in the top-left corner hasn't already - showing it
-        // again here (as "Browse", or as the app's own name) was just the same label twice.
-        if (media.canGoUp || browse.trail.isNotEmpty()) {
-            Row(verticalAlignment = Alignment.CenterVertically) {
-                if (media.canGoUp) {
-                    GsIconButton(Icons.Filled.ArrowBack, "Up", media::up)
-                }
-                browse.trail.lastOrNull()?.let {
-                    Text(
-                        it,
-                        style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold,
-                        maxLines = 1, overflow = TextOverflow.Ellipsis,
-                    )
-                }
-            }
-        }
-        when {
-            browse.loading -> Notice("Loading…", null)
-            browse.unavailable -> Notice(
-                "$appLabel keeps its library to itself.",
-                "Start music in the app on your phone. Play, pause, skip and seek work from here.",
-            )
-            browse.failed -> Notice("Could not load this list.", null)
-            browse.entries.isEmpty() -> Notice("Nothing here.", null)
-            else -> LazyColumn(Modifier.fillMaxSize(), verticalArrangement = Arrangement.spacedBy(8.dp)) {
-                items(browse.entries, key = { it.id }) { entry -> EntryRow(entry, media) }
-            }
-        }
-    }
-}
-
-// --- up next -----------------------------------------------------------------------------------
-
-/**
- * Whatever the app has queued up, starting right after the track that's playing now - not the
- * whole queue from the top, which would just repeat what the player beside it already shows. Apps
- * that never publish a queue (many don't) show an empty notice rather than a permanently blank tab.
- */
-@Composable
-private fun QueuePanel(queue: List<QueueTrack>, now: NowPlaying, media: CarMedia, modifier: Modifier) {
-    val upNext = remember(queue, now.activeQueueItemId) {
-        val current = queue.indexOfFirst { it.queueId == now.activeQueueItemId }
-        if (current >= 0) queue.drop(current + 1) else queue
-    }
-    Column(modifier) {
-        if (upNext.isEmpty()) {
-            Notice(
-                "Nothing queued.",
-                "${if (now.title.isEmpty()) "Nothing playing" else "Only what's already playing"} - " +
-                    "not every app tells Gearslip what comes next.",
-            )
-        } else {
-            LazyColumn(Modifier.fillMaxSize(), verticalArrangement = Arrangement.spacedBy(8.dp)) {
-                items(upNext, key = { it.queueId }) { track -> QueueRow(track, media) }
-            }
-        }
-    }
-}
-
-@Composable
-private fun QueueRow(track: QueueTrack, media: CarMedia) {
-    val context = LocalContext.current
-    val icon by produceState(track.iconBitmap, track.iconUri) {
-        value = track.iconBitmap ?: MediaArt.load(context, track.iconUri)
-    }
-    Surface(
-        onClick = { media.playQueueItem(track) },
-        shape = MaterialTheme.shapes.large,
-        color = MaterialTheme.colorScheme.surfaceVariant,
-        modifier = Modifier.fillMaxWidth(),
-    ) {
-        Row(Modifier.padding(10.dp), verticalAlignment = Alignment.CenterVertically) {
-            Box(Modifier.size(62.dp).clip(MaterialTheme.shapes.medium).background(MaterialTheme.colorScheme.surface)) {
-                icon?.let { Image(it.asImageBitmap(), null, Modifier.fillMaxSize(), contentScale = ContentScale.Crop) }
-            }
-            Column(Modifier.weight(1f).padding(horizontal = 12.dp)) {
-                Text(track.title, style = MaterialTheme.typography.titleSmall, maxLines = 1, overflow = TextOverflow.Ellipsis)
-                if (track.subtitle.isNotEmpty()) {
-                    Text(track.subtitle, style = MaterialTheme.typography.bodySmall, color = MaterialTheme.colorScheme.onSurfaceVariant, maxLines = 1, overflow = TextOverflow.Ellipsis)
-                }
-            }
-            Icon(Icons.Filled.PlayArrow, "Play", tint = MaterialTheme.colorScheme.onSurfaceVariant)
-        }
-    }
-}
-
-@Composable
-private fun EntryRow(entry: MediaEntry, media: CarMedia, onClick: () -> Unit = { media.select(entry) }) {
-    val context = LocalContext.current
-    val icon by produceState(entry.iconBitmap, entry.iconUri) {
-        value = entry.iconBitmap ?: MediaArt.load(context, entry.iconUri)
-    }
-    Surface(
-        onClick = onClick,
-        shape = MaterialTheme.shapes.large,
-        color = MaterialTheme.colorScheme.surfaceVariant,
-        modifier = Modifier.fillMaxWidth(),
-    ) {
-        Row(Modifier.padding(10.dp), verticalAlignment = Alignment.CenterVertically) {
-            Box(Modifier.size(62.dp).clip(MaterialTheme.shapes.medium).background(MaterialTheme.colorScheme.surface)) {
-                icon?.let { Image(it.asImageBitmap(), null, Modifier.fillMaxSize(), contentScale = ContentScale.Crop) }
-            }
-            Column(Modifier.weight(1f).padding(horizontal = 12.dp)) {
-                Text(entry.title, style = MaterialTheme.typography.titleSmall, maxLines = 1, overflow = TextOverflow.Ellipsis)
-                if (entry.subtitle.isNotEmpty()) {
-                    Text(entry.subtitle, style = MaterialTheme.typography.bodySmall, color = MaterialTheme.colorScheme.onSurfaceVariant, maxLines = 1, overflow = TextOverflow.Ellipsis)
-                }
-            }
-            if (entry.browsable && entry.playable) {
-                GsIconButton(Icons.Filled.PlayArrow, "Play", { media.playAll(entry) })
-            }
-            if (entry.browsable) Icon(Icons.AutoMirrored.Filled.KeyboardArrowRight, null)
-        }
-    }
-}
-
-/** Material's transport icons, from their published path data (they live in the extended set). */
-internal object MediaIcons {
-    val Pause = icon("Pause", "M6,19h4L10,5L6,5v14zM14,5v14h4L18,5h-4z")
-    val Next = icon("SkipNext", "M6,18l8.5,-6L6,6v12zM16,6v12h2V6h-2z")
-    /** The 3x3 app grid; not in material-icons-core. */
-    val Apps = icon("Apps", "M4,8h4L8,4L4,4v4zM10,20h4v-4h-4v4zM4,20h4v-4L4,16v4zM4,14h4v-4L4,10v4zM10,14h4v-4h-4v4zM16,4v4h4L20,4h-4zM10,8h4L14,4h-4v4zM16,14h4v-4h-4v4zM16,20h4v-4h-4v4z")
-    val Previous = icon("SkipPrevious", "M6,6h2v12L6,18zM9.5,12l8.5,6V6z")
-    val Equalizer = icon("Equalizer", "M10,20h4L14,4h-4v16zM4,20h4v-8L4,12v8zM16,9v11h4L20,9h-4z")
-    val Shuffle = icon("Shuffle", "M10.59,9.17L5.41,4 4,5.41l5.17,5.17 1.42,-1.41zM14.5,4l2.04,2.04L4,18.59 5.41,20 17.96,7.46 20,9.5L20,4h-5.5zM14.83,13.41l-1.41,1.41 3.13,3.13L14.5,20L20,20v-5.5l-2.04,2.04 -3.13,-3.13z")
-    val Repeat = icon("Repeat", "M7,7h10v3l4,-4 -4,-4v3L5,5v6h2L7,7zM17,17L7,17v-3l-4,4 4,4v-3h12v-6h-2v4z")
-    val RepeatOne = icon("RepeatOne", "M7,7h10v3l4,-4 -4,-4v3L5,5v6h2L7,7zM17,17L7,17v-3l-4,4 4,4v-3h12v-6h-2v4zM13,15L13,9h-1l-2,1v1h1.5v4L13,15z")
-    /** A screen with a filled right-hand panel: "put the player beside the map". */
-    val DockRight = icon("DockRight", "M2,4h20v16H2zM4,6h10v12H4z", PathFillType.EvenOdd)
-
-    private fun icon(name: String, path: String, fillType: PathFillType = PathFillType.NonZero) = ImageVector.Builder(
-        name, 24.dp, 24.dp, 24f, 24f,
-    ).addPath(addPathNodes(path), pathFillType = fillType, fill = SolidColor(androidx.compose.ui.graphics.Color.Black)).build()
-}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/PhoneDialerScreen.kt

@@ -8,6 +8,7 @@ import android.content.pm.PackageManager
 import android.net.Uri
 import android.provider.ContactsContract
 import android.provider.Settings
+import app.seb3thehacker.gearslip.GearslipLog
 import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.interaction.MutableInteractionSource
@@ -80,14 +81,24 @@ internal fun loadContacts(context: Context): List<Contact> {
     return out.distinctBy { it.number }
 }
 
+/**
+ * Places the call through Telecom directly. Starting ACTION_CALL from here launched the system's
+ * call activity onto the car's display, which Android refuses for another app's activity, and
+ * from the background, which it blocks too - so the call never went out.
+ */
 internal fun placeCall(context: Context, number: String) {
     if (number.isBlank()) return
-    if (context.checkSelfPermission(Manifest.permission.CALL_PHONE) != PackageManager.PERMISSION_GRANTED) return
-    runCatching {
-        context.startActivity(
-            Intent(Intent.ACTION_CALL, Uri.parse("tel:${Uri.encode(number)}")).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK),
-        )
+    if (context.checkSelfPermission(Manifest.permission.CALL_PHONE) != PackageManager.PERMISSION_GRANTED) {
+        GearslipLog.w("calls: can't place a call without CALL_PHONE")
+        return
     }
+    val telecom = context.getSystemService(android.telecom.TelecomManager::class.java)
+    runCatching { telecom!!.placeCall(Uri.fromParts("tel", number, null), null) }
+        .onSuccess {
+            GearslipLog.i("calls: placing a call")
+            app.seb3thehacker.gearslip.call.CarCalls.outgoingCall(context, number)
+        }
+        .onFailure { GearslipLog.w("calls: placing a call failed: ${it.message}") }
 }
 
 /** A call another car screen wants to place - a number on a place page - waiting on the driver. */
@@ -122,7 +133,7 @@ private const val TAB_KEYPAD = 1
 @Composable
 fun PhoneDialerScreen() {
     val context = LocalContext.current
-    val hasPermissions = hasCallPermissions(context)
+    var hasPermissions by remember { mutableStateOf(hasCallPermissions(context)) }
     var tab by remember { mutableStateOf(TAB_CONTACTS) }
 
     Column(Modifier.fillMaxSize().padding(16.dp), verticalArrangement = Arrangement.spacedBy(16.dp)) {
@@ -137,7 +148,7 @@ fun PhoneDialerScreen() {
         }
 
         if (!hasPermissions) {
-            MissingPermission(context)
+            MissingPermission(context) { hasPermissions = true }
             return@Column
         }
 
@@ -148,19 +159,23 @@ fun PhoneDialerScreen() {
 }
 
 @Composable
-private fun MissingPermission(context: Context) {
+private fun MissingPermission(context: Context, onGranted: () -> Unit) {
+    // Android's dialog can't show on the car screen, so it opens on the phone; checking again
+    // every second picks the answer up without the driver having to come back in.
+    androidx.compose.runtime.LaunchedEffect(Unit) {
+        while (!hasCallPermissions(context)) kotlinx.coroutines.delay(1_000)
+        onGranted()
+    }
     Column(verticalArrangement = Arrangement.spacedBy(12.dp)) {
         Text(
-            "Gearslip needs the Phone and Contacts permissions to dial from here. Grant them " +
-                "from the app's settings.",
+            "Gearslip needs the Phone and Contacts permissions to dial from here. Allow them on " +
+                "the phone when you're parked.",
             style = MaterialTheme.typography.bodyLarge,
             color = MaterialTheme.colorScheme.onSurfaceVariant,
         )
         GsButton(tone = GsTone.Tonal, onClick = {
-            context.startActivity(
-                Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS, Uri.fromParts("package", context.packageName, null)),
-            )
-        }) { Text("Open app settings") }
+            app.seb3thehacker.gearslip.PermissionActivity.ask(context, CALL_PERMISSIONS)
+        }) { Text("Ask on the phone") }
     }
 }
 

gearslip/src/main/java/app/seb3thehacker/gearslip/car/TemplateChrome.kt

@@ -2,6 +2,13 @@ package app.seb3thehacker.gearslip.car
 
 import app.seb3thehacker.gearslip.car.theme.*
 import android.graphics.Rect
+import androidx.compose.foundation.layout.widthIn
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.compositionLocalOf
+import androidx.compose.runtime.mutableStateMapOf
+import androidx.compose.ui.layout.boundsInWindow
+import androidx.compose.ui.layout.onGloballyPositioned
+import androidx.compose.ui.geometry.Rect as ComposeRect
 import androidx.compose.foundation.Image
 import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Arrangement
@@ -10,6 +17,7 @@ import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
@@ -86,87 +94,203 @@ fun TemplateChrome(template: Template?, modifier: Modifier = Modifier) {
  * How much of the surface Gearslip's chrome covers, so the app can keep what matters clear of
  * it. Expressed as the visible rectangle within a [width] x [height] surface.
  *
+ * Navigation's cards are measured where they land ([measured], from [ChromeCover]); an app
+ * centres its position marker in this rectangle, so a guess puts the marker under the card.
  * A template that isn't map-backed covers the surface completely, and reporting an empty
  * rectangle is how the app is told to stop bothering.
  */
-fun visibleAreaFor(template: Template?, width: Int, height: Int): Rect = when (template) {
-    is NavigationTemplate -> Rect(0, 0, width, (height * (1f - ESTIMATE_FRACTION)).toInt())
+fun visibleAreaFor(template: Template?, width: Int, height: Int, measured: Rect? = null): Rect = when (template) {
+    is NavigationTemplate -> measured ?: Rect(0, 0, width, height)
     is MapWithContentTemplate, is MapTemplate, is PlaceListNavigationTemplate,
     is RoutePreviewNavigationTemplate, is PlaceListMapTemplate,
-    -> Rect((width * CONTENT_PANE_FRACTION).toInt(), 0, width, height)
+    -> measured ?: Rect((width * CARD_COLUMN_FRACTION).toInt(), 0, width, height)
     null -> Rect(0, 0, width, height)
     else -> Rect(0, 0, 0, 0)
 }
 
+/** The side of the map a piece of chrome sits against, and so the side it shrinks the visible area from. */
+internal enum class CoverEdge { TOP, BOTTOM, START, END }
+
+/**
+ * Where the chrome over the map actually landed, in window pixels. The map buttons count even
+ * while faded out, or whatever an app draws in a corner (Waze's speedometer) is under them the
+ * moment they come back.
+ */
+internal class ChromeCover {
+    private val pieces = mutableStateMapOf<String, Pair<CoverEdge, ComposeRect>>()
+
+    fun put(key: String, edge: CoverEdge, bounds: ComposeRect) {
+        val piece = edge to bounds
+        if (pieces[key] != piece) pieces[key] = piece
+    }
+
+    fun remove(key: String) {
+        pieces.remove(key)
+    }
+
+    /** What is left of a [width] x [height] surface at [surface] (window pixels), in surface pixels. */
+    fun visibleWithin(surface: ComposeRect, width: Int, height: Int, skip: CoverEdge? = null): Rect {
+        var left = 0f
+        var top = 0f
+        var right = width.toFloat()
+        var bottom = height.toFloat()
+        pieces.values.forEach { (edge, b) ->
+            if (edge == skip) return@forEach
+            when (edge) {
+                CoverEdge.TOP -> top = maxOf(top, b.bottom - surface.top)
+                CoverEdge.BOTTOM -> bottom = minOf(bottom, b.top - surface.top)
+                CoverEdge.START -> left = maxOf(left, b.right - surface.left)
+                CoverEdge.END -> right = minOf(right, b.left - surface.left)
+            }
+        }
+        // Never hand an app nothing to draw in, however the cards end up.
+        if (right - left < width / 4f) { left = 0f; right = width.toFloat() }
+        if (bottom - top < height / 4f) { top = 0f; bottom = height.toFloat() }
+        return Rect(left.toInt(), top.toInt(), right.toInt(), bottom.toInt())
+    }
+}
+
+internal val LocalChromeCover = compositionLocalOf<ChromeCover?> { null }
+
+/**
+ * The floating nav bar, as far as the app's map is concerned. Its full [height] at once rather
+ * than following the slide, so the app is told once instead of every frame.
+ */
+@Composable
+internal fun BottomCover(height: androidx.compose.ui.unit.Dp, modifier: Modifier = Modifier) {
+    Box(modifier.fillMaxWidth().height(height).covers("nav-bar", CoverEdge.BOTTOM))
+}
+
+/** Records where this lands, padding included, until it leaves the screen. */
+@Composable
+internal fun Modifier.covers(key: String, edge: CoverEdge): Modifier {
+    val cover = LocalChromeCover.current ?: return this
+    DisposableEffect(cover, key) { onDispose { cover.remove(key) } }
+    return onGloballyPositioned { cover.put(key, edge, it.boundsInWindow()) }
+}
+
 // --- navigation ------------------------------------------------------------------------------
 
 @Composable
 private fun NavigationChrome(template: NavigationTemplate, modifier: Modifier) {
-    val pan by CarServices.nav.panMode.collectAsState()
-    Box(modifier.fillMaxWidth()) {
-        if (!pan) (template.navigationInfo as? RoutingInfo)?.let {
-            RoutingCard(it, Modifier.align(Alignment.TopStart).padding(12.dp).width(320.dp))
-        }
-        RightEdgeControls(
-            if (pan) null else template.actionStrip,
-            template.mapActionStrip,
-            Modifier.align(Alignment.TopEnd).padding(12.dp),
-        )
-        if (!pan) template.destinationTravelEstimate?.let {
-            TravelEstimateBar(it, Modifier.align(Alignment.BottomStart).padding(12.dp))
+    val connection = LocalCarAppConnection.current
+    val pan by connection.panMode.collectAsState()
+    // Pan mode clears the map for looking around: only the buttons stay.
+    val routing = (template.navigationInfo as? RoutingInfo)?.takeUnless { pan }
+    val estimate = template.destinationTravelEstimate?.takeUnless { pan }
+    NavigationBars(template, routing, estimate, modifier)
+}
+
+/**
+ * Cards down the left, map on the right: the turn on top, the trip along the bottom, the map
+ * buttons at the right edge. The whole column counts as covered, so the app centres its map in
+ * what is left over and the car sits right of the cards rather than under them. Pan mode drops
+ * the cards and gives the map the whole width.
+ */
+@Composable
+private fun NavigationBars(
+    template: NavigationTemplate,
+    routing: RoutingInfo?,
+    estimate: TravelEstimate?,
+    modifier: Modifier,
+) {
+    val connection = LocalCarAppConnection.current
+    val pan by connection.panMode.collectAsState()
+    androidx.compose.foundation.layout.BoxWithConstraints(modifier.fillMaxSize()) {
+        val column = cardColumnWidth(maxWidth)
+        Row(Modifier.fillMaxSize()) {
+            if (routing != null || estimate != null) {
+                Column(
+                    Modifier.width(column).fillMaxHeight().covers("nav-cards", CoverEdge.START).padding(12.dp),
+                    verticalArrangement = Arrangement.spacedBy(12.dp),
+                ) {
+                    routing?.let { RoutingCard(it, Modifier.fillMaxWidth()) }
+                    Spacer(Modifier.weight(1f))
+                    estimate?.let { TravelEstimateCard(it, Modifier.fillMaxWidth()) }
+                }
+            }
+            Spacer(Modifier.weight(1f))
+            RightEdgeControls(
+                if (pan) null else template.actionStrip,
+                template.mapActionStrip,
+                Modifier.padding(12.dp),
+                mapActionsModifier = Modifier.covers("nav-buttons", CoverEdge.END),
+            )
         }
     }
 }
 
-/** The manoeuvre card: what to do next, how far away it is, and onto what road. */
+/**
+ * The manoeuvre, big enough to read at a glance: the arrow and the distance to it, what to do
+ * and onto which road, the lanes to be in, and the turn after it along the bottom.
+ */
 @Composable
 private fun RoutingCard(info: RoutingInfo, modifier: Modifier = Modifier) {
     if (info.isLoading) {
         ChromeSurface(modifier) {
-            Text("Finding a route…", Modifier.padding(16.dp), style = ChromeType.title)
+            Text("Finding a route…", Modifier.padding(horizontal = 18.dp, vertical = 16.dp), style = ChromeType.title)
         }
         return
     }
 
     val step = info.currentStep ?: return
+    val scheme = MaterialTheme.colorScheme
     ChromeSurface(modifier) {
-        Column(Modifier.padding(14.dp)) {
-            Row(verticalAlignment = Alignment.CenterVertically) {
-                CarGlyph(step.maneuver?.icon, Modifier.size(44.dp))
-                Spacer(Modifier.width(12.dp))
-                Column(Modifier.weight(1f)) {
-                    val distance = info.currentDistance.display()
-                    if (distance.isNotEmpty()) {
-                        Text(distance, style = ChromeType.headline)
+        Column {
+            Column(
+                Modifier.fillMaxWidth().background(scheme.primaryContainer).padding(16.dp),
+                verticalArrangement = Arrangement.spacedBy(8.dp),
+            ) {
+                androidx.compose.runtime.CompositionLocalProvider(
+                    androidx.compose.material3.LocalContentColor provides scheme.onPrimaryContainer,
+                ) {
+                    Row(verticalAlignment = Alignment.CenterVertically) {
+                        CarGlyph(step.maneuver?.icon, Modifier.size(64.dp))
+                        Spacer(Modifier.width(14.dp))
+                        val distance = info.currentDistance.display()
+                        if (distance.isNotEmpty()) {
+                            Text(
+                                distance,
+                                style = MaterialTheme.typography.displaySmall.copy(fontWeight = androidx.compose.ui.text.font.FontWeight.Bold),
+                                maxLines = 1,
+                            )
+                        }
                     }
-                    Text(step.cue.text(), style = ChromeType.title, maxLines = 2, overflow = TextOverflow.Ellipsis)
+                    val cue = step.cue.text()
+                    if (cue.isNotEmpty()) {
+                        Text(cue, style = ChromeType.title, maxLines = 2, overflow = TextOverflow.Ellipsis)
+                    }
+                    val road = step.road.text()
+                    // "Turn left onto Queensberry Drive" already says the road; saying it twice is noise.
+                    if (road.isNotEmpty() && !cue.contains(road, ignoreCase = true)) {
+                        Text(
+                            road,
+                            style = ChromeType.body,
+                            color = scheme.onPrimaryContainer.copy(alpha = 0.8f),
+                            maxLines = 1,
+                            overflow = TextOverflow.Ellipsis,
+                        )
+                    }
+                    if (step.lanesImage != null || step.lanes.orEmpty().isNotEmpty()) {
+                        LaneGuidance(step, Modifier.fillMaxWidth().heightIn(max = 56.dp))
+                    }
+                    // Rare, and only where an arrow can't explain the junction: worth the card growing for.
+                    info.junctionImage?.let { JunctionImage(it) }
                 }
             }
-            val road = step.road.text()
-            if (road.isNotEmpty()) {
-                Text(
-                    road,
-                    style = ChromeType.body,
-                    color = MaterialTheme.colorScheme.onSurfaceVariant,
-                    maxLines = 1,
-                    overflow = TextOverflow.Ellipsis,
-                )
-            }
-            // Neither is sent by every app - most say only "turn left" and trust the driver to
-            // find the lane themselves - so both are drawn only when there is something to draw.
-            info.junctionImage?.let { junction ->
-                Spacer(Modifier.height(10.dp))
-                JunctionImage(junction)
-            }
-            LaneGuidance(step, Modifier.padding(top = 10.dp))
             info.nextStep?.let { next ->
-                Spacer(Modifier.height(8.dp))
-                Row(verticalAlignment = Alignment.CenterVertically) {
-                    Text("then", style = ChromeType.label, color = MaterialTheme.colorScheme.onSurfaceVariant)
-                    Spacer(Modifier.width(8.dp))
-                    CarGlyph(next.maneuver?.icon, Modifier.size(20.dp))
-                    Spacer(Modifier.width(8.dp))
-                    Text(next.cue.text(), style = ChromeType.body, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                Row(
+                    Modifier.fillMaxWidth().padding(horizontal = 16.dp, vertical = 10.dp),
+                    verticalAlignment = Alignment.CenterVertically,
+                ) {
+                    Text("Then", style = ChromeType.label, color = scheme.onSurfaceVariant)
+                    Spacer(Modifier.width(10.dp))
+                    CarGlyph(next.maneuver?.icon, Modifier.size(28.dp))
+                    val nextText = next.cue.text().ifEmpty { next.road.text() }
+                    if (nextText.isNotEmpty()) {
+                        Spacer(Modifier.width(10.dp))
+                        Text(nextText, style = ChromeType.body, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                    }
                 }
             }
         }
@@ -243,63 +367,59 @@ private fun LaneDirection?.turnDegrees(): Float = when (this?.shape) {
 }
 
 /**
- * The trip at a glance: time and distance left, the clock time it ends at, and - beside them,
- * where a thumb reaches - the app's own way to stop navigating. A floating card rather than a
- * full-width bar, so it reads as one thing beside the manoeuvre card above it instead of a strip
- * that happens to hold three numbers. The close button is Gearslip's own, not the app's: an
- * actionStrip's actions carry no flag saying which one (if any) means "stop navigating" - the
- * first button here turned out to be a mute toggle, not an exit - so this leaves the app the way
- * going Home already does, rather than guess at the app's own controls and risk getting it wrong.
+ * The trip at a glance, stacked: time left on top, then the clock time it ends at and the
+ * distance, with Gearslip's own stop button beside them. The close button is Gearslip's, not the
+ * app's: an actionStrip's actions carry no flag saying which one (if any) means "stop
+ * navigating" - the first button turned out to be a mute toggle, not an exit - so this ends
+ * navigation the way going Home already does rather than guess at the app's own controls.
  */
 @Composable
-private fun TravelEstimateBar(estimate: TravelEstimate, modifier: Modifier = Modifier) {
+private fun TravelEstimateCard(estimate: TravelEstimate, modifier: Modifier = Modifier) {
+    val connection = LocalCarAppConnection.current
     val time = remainingTime(estimate.remainingTimeSeconds)
     val distance = estimate.remainingDistance.display()
     val arrival = estimate.arrivalTimeAtDestination.clockTime()
     val trip = estimate.tripText.text()
     if (time.isEmpty() && distance.isEmpty() && arrival.isEmpty() && trip.isEmpty()) return
 
-    val detail = listOfNotNull(
-        arrival.takeIf { it.isNotEmpty() },
-        distance.takeIf { it.isNotEmpty() },
-        trip.takeIf { it.isNotEmpty() },
-    ).joinToString("  •  ")
-
-    // The same solid card the manoeuvre card above it uses - one surface for the whole map
-    // chrome, rather than this one spot styled on its own as a bar over the map.
-    ChromeSurface(modifier, shadowElevation = 8.dp) {
+    ChromeSurface(modifier) {
         val dark = MaterialTheme.colorScheme.surface.luminanceIsDark()
         Row(
-            Modifier.padding(start = 8.dp, end = 18.dp, top = 10.dp, bottom = 10.dp),
+            Modifier.padding(start = 18.dp, end = 12.dp, top = 12.dp, bottom = 12.dp),
             verticalAlignment = Alignment.CenterVertically,
         ) {
-            // Not a disconnect: the connection stays up and the app decides its own next screen.
-            // Ending navigation is its own call, separate from a back press - a back press only
-            // pops the on-screen card, leaving the app still believing it is navigating (so a
-            // freshly picked destination silently does nothing); this is the call that actually
-            // clears that flag on the app's side.
-            GsIconButton(
-                Icons.Filled.Close,
-                "Stop navigating",
-                { CarServices.nav.stopNavigating() },
-                colors = GsColors(MaterialTheme.colorScheme.surfaceContainerHighest, MaterialTheme.colorScheme.onSurface),
-                size = 40.dp,
-                iconSize = 20.dp,
-                shape = CircleShape,
-            )
-            Spacer(Modifier.width(10.dp))
-            Column {
+            Column(Modifier.weight(1f)) {
                 if (time.isNotEmpty()) {
                     Text(
                         time,
                         style = ChromeType.headline,
                         color = estimate.remainingTimeColor.color(dark, MaterialTheme.colorScheme.onSurface),
+                        maxLines = 1,
                     )
                 }
+                val detail = listOfNotNull(
+                    arrival.takeIf { it.isNotEmpty() }?.let { "Arrive $it" },
+                    distance.takeIf { it.isNotEmpty() },
+                ).joinToString("  •  ")
                 if (detail.isNotEmpty()) {
-                    Text(detail, style = ChromeType.body, color = MaterialTheme.colorScheme.onSurfaceVariant)
+                    Text(detail, style = ChromeType.body, color = MaterialTheme.colorScheme.onSurfaceVariant, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                }
+                if (trip.isNotEmpty()) {
+                    Text(trip, style = ChromeType.body, color = MaterialTheme.colorScheme.onSurfaceVariant, maxLines = 1, overflow = TextOverflow.Ellipsis)
                 }
             }
+            // Not a disconnect: the connection stays up and the app decides its own next screen.
+            // Ending navigation is its own call, separate from a back press - a back press only
+            // pops the on-screen card, leaving the app still believing it is navigating.
+            GsIconButton(
+                Icons.Filled.Close,
+                "Stop navigating",
+                { connection.stopNavigating() },
+                colors = GsColors(MaterialTheme.colorScheme.surfaceContainerHighest, MaterialTheme.colorScheme.onSurface),
+                size = 52.dp,
+                iconSize = 26.dp,
+                shape = CircleShape,
+            )
         }
     }
 }
@@ -321,16 +441,18 @@ private fun MapPaneLayout(
     fullHeight: Boolean = false,
     pane: @Composable () -> Unit,
 ) {
+    val connection = LocalCarAppConnection.current
     // Pan mode hands the whole screen to the map, leaving only its own controls.
-    val pan by CarServices.nav.panMode.collectAsState()
+    val pan by connection.panMode.collectAsState()
     val edgeActions = (actionStrip?.actions.orEmpty() + mapActionStrip?.actions.orEmpty()).map { it.identity() }.toSet()
     androidx.compose.foundation.layout.BoxWithConstraints(modifier.fillMaxWidth()) {
         if (!pan) {
             ChromeSurface(
                 Modifier
                     .align(Alignment.TopStart)
+                    .covers("map-pane", CoverEdge.START)
                     .padding(12.dp)
-                    .width(maxOf(maxWidth * CONTENT_PANE_FRACTION - 12.dp, 232.dp))
+                    .width(cardColumnWidth(maxWidth) - 24.dp)
                     .let { if (fullHeight) it.height(maxHeight - 24.dp) else it.heightIn(max = maxHeight - 24.dp) },
                 shape = androidx.compose.foundation.shape.RoundedCornerShape(20.dp),
                 shadowElevation = 8.dp,
@@ -451,11 +573,16 @@ private fun ListPane(
     }
 }
 
-/** Fraction of the surface the content pane covers beside a map. */
-private const val CONTENT_PANE_FRACTION = 0.42f
 
-/** Fraction of the surface the travel-estimate bar covers along the bottom. */
-private const val ESTIMATE_FRACTION = 0.14f
+
+/**
+ * The width of the cards beside the map, the same for a place card and for navigation so the
+ * map doesn't jump sideways when a route starts.
+ */
+internal fun cardColumnWidth(maxWidth: androidx.compose.ui.unit.Dp): androidx.compose.ui.unit.Dp =
+    (maxWidth * CARD_COLUMN_FRACTION).coerceIn(280.dp, 440.dp).coerceAtMost(maxWidth)
+
+private const val CARD_COLUMN_FRACTION = 0.4f
 
 /** Search, sign-in and the like are laid out for a whole column, so they keep one. */
 private fun Template?.needsFullHeight() =

gearslip/src/main/java/app/seb3thehacker/gearslip/car/TemplateContent.kt

@@ -517,7 +517,8 @@ private val sectionCache = android.util.LruCache<String, List<Item>>(64)
  */
 @Composable
 private fun SectionedContent(template: SectionedItemTemplate, modifier: Modifier, showActionsInHeader: Boolean = true, tabId: String = "") {
-    val appPackage = CarServices.nav.appPackage.orEmpty()
+    val connection = LocalCarAppConnection.current
+    val appPackage = connection.appPackage.orEmpty()
     ContentSurface(modifier) {
         // The app's own actions (Spotify's search and Liked Songs shortcut, for two) come from
         // template.actions, not the header - but a bottom-of-content row is wrong for a driver

gearslip/src/main/java/app/seb3thehacker/gearslip/car/TemplateParts.kt

@@ -106,7 +106,8 @@ internal fun ChromeSurface(
 ) {
     Surface(
         shadowElevation = shadowElevation,
-        color = MaterialTheme.colorScheme.surface,
+        // The nav bar's own container colour, so cards over the map match the rest of the car UI.
+        color = MaterialTheme.colorScheme.surfaceContainer,
         contentColor = MaterialTheme.colorScheme.onSurface,
         shape = shape,
         modifier = modifier,
@@ -217,28 +218,34 @@ internal fun headerTitle(header: Header?, fallback: String): String =
  * actions in a row along the top, its map controls stacked under them. Keeping them in one
  * column is what stops them colliding on a screen only 480px tall.
  */
+/** How visible the map buttons stay once they fade: enough to know they're there. */
+private const val RESTING_ALPHA = 0.35f
+
 @Composable
 internal fun RightEdgeControls(
     actionStrip: ActionStrip?,
     mapActionStrip: ActionStrip?,
     modifier: Modifier = Modifier,
+    /** For the stack of map buttons alone, without the row of the app's own above it. */
+    mapActionsModifier: Modifier = Modifier,
 ) {
+    val connection = LocalCarAppConnection.current
     val actions = actionStrip?.actions.orEmpty().filter { it.isDrawable() }
     val mapActions = mapActionStrip?.actions.orEmpty().filter { it.isDrawable() }
     if (actions.isEmpty() && mapActions.isEmpty()) return
     // A template that stops offering Pan must not leave the screen stuck in pan mode.
     val hasPan = (actions + mapActions).any { it.type == Action.TYPE_PAN }
-    androidx.compose.runtime.LaunchedEffect(hasPan) { if (!hasPan) CarServices.nav.setPanMode(false) }
+    androidx.compose.runtime.LaunchedEffect(hasPan) { if (!hasPan) connection.setPanMode(false) }
 
     // Faded out when the screen has been left alone; then they are only a memory of buttons, so
     // the first touch on one wakes them rather than pressing it.
     val awake = LocalMapControlsWake.current.awake
-    val pan by CarServices.nav.panMode.collectAsState()
+    val pan by connection.panMode.collectAsState()
     // Kept up while the knob is on one of them, or the ring would fade out along with the button.
     var holdsFocus by remember { mutableStateOf(false) }
     val visible = awake || pan || holdsFocus
     val alpha by androidx.compose.animation.core.animateFloatAsState(
-        targetValue = if (visible) 1f else 0f,
+        targetValue = if (visible) 1f else RESTING_ALPHA,
         animationSpec = androidx.compose.animation.core.tween(if (visible) 150 else 500),
         label = "mapControls",
     )
@@ -263,7 +270,15 @@ internal fun RightEdgeControls(
                 actions.forEach { ActionButton(it) }
             }
         }
-        mapActions.forEach { ActionButton(it) }
+        if (mapActions.isNotEmpty()) {
+            Column(
+                mapActionsModifier,
+                horizontalAlignment = Alignment.End,
+                verticalArrangement = Arrangement.spacedBy(8.dp),
+            ) {
+                mapActions.forEach { ActionButton(it) }
+            }
+        }
     }
 }
 
@@ -278,7 +293,7 @@ internal fun ActionRow(actions: List<Action>, modifier: Modifier = Modifier, lar
 }
 
 /** A row with nothing to show: no words, no picture, nothing to tap. */
-private fun CarRow.isBlank(): Boolean =
+internal fun CarRow.isBlank(): Boolean =
     title.text().isBlank() && texts.orEmpty().all { it.text().isBlank() } && image == null &&
         toggle == null && onClickDelegate == null && actions.orEmpty().isEmpty()
 
@@ -288,13 +303,14 @@ private fun CarRow.isBlank(): Boolean =
  */
 @Composable
 internal fun ActionButton(action: Action, large: Boolean = false, modifier: Modifier = Modifier) {
+    val connection = LocalCarAppConnection.current
     if (action.type == Action.TYPE_APP_ICON) {
         AppIconBadge()
         return
     }
     val dark = MaterialTheme.colorScheme.surface.luminanceIsDark()
     val title = action.title.text()
-    val panOn by CarServices.nav.panMode.collectAsState()
+    val panOn by connection.panMode.collectAsState()
     val active = action.type == Action.TYPE_PAN && panOn
     val scheme = MaterialTheme.colorScheme
     val custom = action.backgroundColor?.type?.let { it != androidx.car.app.model.CarColor.TYPE_DEFAULT } == true
@@ -309,8 +325,8 @@ internal fun ActionButton(action: Action, large: Boolean = false, modifier: Modi
 
     GsIconBox(
         onClick = {
-            if (action.type == Action.TYPE_BACK) CarServices.nav.backPressed()
-            else if (action.type == Action.TYPE_PAN) CarServices.nav.setPanMode(!panOn)
+            if (action.type == Action.TYPE_BACK) connection.backPressed()
+            else if (action.type == Action.TYPE_PAN) connection.setPanMode(!panOn)
             else action.onClickDelegate?.click("action")
         },
         modifier = modifier,
@@ -421,8 +437,9 @@ private const val AUTO_START_MS = 5_000L
 /** The connected app's own launcher icon, which is what the app-icon action stands for. */
 @Composable
 private fun AppIconBadge() {
+    val connection = LocalCarAppConnection.current
     val context = LocalContext.current
-    val pkg = CarServices.nav.appPackage
+    val pkg = connection.appPackage
     val icon = remember(pkg) {
         pkg?.let {
             runCatching {
@@ -497,315 +514,6 @@ internal fun CarGlyph(icon: CarIcon?, modifier: Modifier = Modifier, standard: I
 
 // --- lists, grids and panes ---------------------------------------------------------------------
 
-@Composable
-internal fun PaneTitle(title: String) {
-    if (title.isEmpty()) return
-    Text(
-        title,
-        style = ChromeType.title,
-        modifier = Modifier.padding(horizontal = 14.dp, vertical = 10.dp),
-    )
-}
-
-@Composable
-internal fun ItemListColumn(
-    single: ItemList?,
-    sectioned: List<ItemList>? = null,
-    modifier: Modifier = Modifier,
-) {
-    val rows = buildList {
-        single?.items?.filterIsInstance<CarRow>()?.let(::addAll)
-        sectioned?.forEach { list -> addAll(list.items.filterIsInstance<CarRow>()) }
-    }
-    if (rows.isEmpty()) {
-        val message = single?.noItemsMessage.text()
-        if (message.isNotEmpty()) Text(message, Modifier.padding(14.dp), style = ChromeType.body)
-        return
-    }
-    // A list the app made selectable is a single-choice list: one option chosen, shown as a radio.
-    val onSelected = single?.onSelectedDelegate
-    val chosen = single?.selectedIndex ?: -1
-    LazyColumn(modifier, contentPadding = PaddingValues(bottom = 8.dp)) {
-        itemsIndexed(rows) { index, row ->
-            RowItem(row, onSelected?.let { RowSelection(index == chosen) { it.selected(index) } })
-        }
-    }
-}
-
-/** A grid of tappable tiles - what apps use for a home screen beside the map. Icons here are as
- * often a small menu glyph (Organic Maps' Search, say) as real cover art, so the tile stays
- * modest; [GridTile]'s own default is for the shelf case, where every tile is a photo. */
-@Composable
-internal fun GridItems(list: ItemList?, modifier: Modifier = Modifier) {
-    val items = list?.items?.filterIsInstance<GridItem>().orEmpty()
-    if (items.isEmpty()) return
-    LazyVerticalGrid(
-        columns = GridCells.Adaptive(84.dp),
-        modifier = modifier,
-        contentPadding = PaddingValues(horizontal = 8.dp, vertical = 4.dp),
-        horizontalArrangement = Arrangement.spacedBy(6.dp),
-        verticalArrangement = Arrangement.spacedBy(6.dp),
-    ) {
-        items(items) { item -> GridTile(item, iconSize = 36.dp) }
-    }
-}
-
-/**
- * One cover-art tile: an app's own icon over a title and optional subtitle. Shared by
- * [GridItems] (a whole screen of tiles, [iconSize] scaled down there to suit a plain menu glyph)
- * and a section's horizontal shelf, which carries the same [GridItem] type but scrolls sideways
- * instead of wrapping into a grid and wants its full-size cover art.
- */
-@Composable
-internal fun GridTile(item: GridItem, modifier: Modifier = Modifier, iconSize: androidx.compose.ui.unit.Dp = 144.dp) {
-    Column(
-        modifier
-            .clickable { item.onClickDelegate.click("grid item") }
-            .padding(vertical = 8.dp),
-        horizontalAlignment = Alignment.CenterHorizontally,
-    ) {
-        CarGlyph(item.image, Modifier.size(iconSize))
-        Spacer(Modifier.height(6.dp))
-        Text(
-            item.title.text(),
-            style = ChromeType.label,
-            maxLines = 1,
-            overflow = TextOverflow.Ellipsis,
-        )
-        val subtitle = item.text.text()
-        if (subtitle.isNotEmpty()) {
-            Text(
-                subtitle,
-                style = ChromeType.label,
-                color = MaterialTheme.colorScheme.onSurfaceVariant,
-                maxLines = 1,
-                overflow = TextOverflow.Ellipsis,
-            )
-        }
-    }
-}
-
-/**
- * [autoStart] is for a pane floating over a map - a place or a route the app is proposing - where
- * a single action counts itself down rather than waiting to be pressed, on the theory that a
- * driver glancing at the car screen has already decided. It never applies to more than one
- * action: a pane offering a real choice (Start vs. something else) always waits to be tapped.
- */
-@Composable
-internal fun PaneRows(pane: Pane?, modifier: Modifier = Modifier, autoStart: Boolean = false) {
-    // Some apps pad a pane with a row of blank strings; drawn, it is just a gap.
-    val rows = pane?.rows.orEmpty().filterNot { it.isBlank() }
-    val actions = pane?.actions.orEmpty().filter { it.isDrawable() }
-    val card = PlaceCard.of(rows)
-    Column(modifier) {
-        card.heading?.let { PlaceHeading(it) }
-        if (card.buttons.isNotEmpty()) RowButtons(card.buttons, Modifier.padding(horizontal = 14.dp, vertical = 6.dp))
-        if (autoStart && actions.size == 1) {
-            AutoStartButton(actions.single(), Modifier.padding(horizontal = 14.dp, vertical = 10.dp))
-        } else {
-            ActionRow(actions, Modifier.padding(horizontal = 14.dp, vertical = 10.dp), large = true)
-        }
-        if (card.heading == null && card.buttons.isEmpty()) {
-            card.details.forEach { RowItem(it, large = true) }
-        } else {
-            card.details.forEach { DetailRow(it, card.heading?.title?.text().orEmpty()) }
-        }
-    }
-}
-
-/**
- * A pane split the way a place page reads: a name on top, the things to do with it as buttons,
- * then the facts. Apps send all three as plain rows, so the split is worked out from the rows'
- * shape alone. A pane that doesn't fit the shape - all of it tappable, like a menu - gets no
- * heading and no buttons, and draws exactly as a plain list of rows.
- */
-private class PlaceCard(val heading: CarRow?, val buttons: List<CarRow>, val details: List<CarRow>) {
-    companion object {
-        fun of(rows: List<CarRow>): PlaceCard {
-            // A short tappable row with an icon and nothing under it is a button in all but name:
-            // MAPS.ME's "Let's go" and "Save".
-            val buttons = rows.filter {
-                it.onClickDelegate != null && it.toggle == null && it.image != null &&
-                    it.texts.orEmpty().isEmpty() && it.title.text().length <= 24
-            }.takeIf { it.size in 1..4 && it.size < rows.size }.orEmpty()
-            // A first row that can't be tapped and has no icon is the place's name and kind.
-            val heading = rows.firstOrNull()?.takeIf {
-                buttons.isNotEmpty() && it.onClickDelegate == null && it.image == null && it.toggle == null
-            }
-            return PlaceCard(heading, buttons, rows - buttons.toSet() - listOfNotNull(heading).toSet())
-        }
-    }
-}
-
-@Composable
-private fun PlaceHeading(row: CarRow) {
-    Column(Modifier.fillMaxWidth().padding(horizontal = 14.dp, vertical = 6.dp)) {
-        Text(row.title.text(), style = ChromeType.title, maxLines = 2, overflow = TextOverflow.Ellipsis)
-        row.texts.orEmpty().take(2).forEach {
-            Text(it.text(), style = ChromeType.body, color = MaterialTheme.colorScheme.onSurfaceVariant, maxLines = 1, overflow = TextOverflow.Ellipsis)
-        }
-    }
-}
-
-/** Button-shaped rows side by side, the first one filled as the thing most drivers came to do. */
-@Composable
-private fun RowButtons(rows: List<CarRow>, modifier: Modifier) {
-    val scheme = MaterialTheme.colorScheme
-    Row(modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(8.dp)) {
-        rows.forEachIndexed { i, row ->
-            GsIconBox(
-                onClick = { row.onClickDelegate.click("row") },
-                modifier = Modifier.weight(1f),
-                colors = if (i == 0) GsColors(scheme.primary, scheme.onPrimary) else GsColors(scheme.surfaceContainerHighest, scheme.onSurface),
-                enabled = row.isEnabled,
-                shape = RoundedCornerShape(24.dp),
-            ) {
-                Row(
-                    Modifier.fillMaxWidth().padding(horizontal = 16.dp, vertical = 14.dp),
-                    horizontalArrangement = Arrangement.Center,
-                    verticalAlignment = Alignment.CenterVertically,
-                ) {
-                    CarGlyph(row.image, Modifier.size(24.dp))
-                    Spacer(Modifier.width(8.dp))
-                    Text(row.title.text(), style = ChromeType.body, maxLines = 1, overflow = TextOverflow.Ellipsis)
-                }
-            }
-        }
-    }
-}
-
-/**
- * One fact about a place, tighter than a list row: a small label over its value, or just the
- * value when the row has no label. A phone number gets a Call button that asks first.
- */
-@Composable
-private fun DetailRow(row: CarRow, placeName: String) {
-    val context = LocalContext.current
-    val texts = row.texts.orEmpty().map { it.text() }.filter { it.isNotBlank() }
-    val label = row.title.text().takeIf { texts.isNotEmpty() }
-    val values = texts.ifEmpty { listOf(row.title.text()) }
-    val number = values.firstOrNull { it.isPhoneNumber() }
-    val canCall = number != null &&
-        context.checkSelfPermission(android.Manifest.permission.CALL_PHONE) == android.content.pm.PackageManager.PERMISSION_GRANTED
-    Row(
-        Modifier
-            .fillMaxWidth()
-            .let { if (row.onClickDelegate != null && row.isEnabled) it.clickable { row.onClickDelegate.click("row") } else it }
-            .padding(horizontal = 14.dp, vertical = 6.dp),
-        verticalAlignment = Alignment.CenterVertically,
-    ) {
-        row.image?.let {
-            CarGlyph(it, Modifier.size(24.dp))
-            Spacer(Modifier.width(12.dp))
-        }
-        Column(Modifier.weight(1f)) {
-            label?.let {
-                Text(it, style = MaterialTheme.typography.labelLarge, color = MaterialTheme.colorScheme.onSurfaceVariant, maxLines = 1)
-            }
-            values.take(3).forEach {
-                Text(it, style = ChromeType.body, maxLines = 2, overflow = TextOverflow.Ellipsis)
-            }
-        }
-        if (canCall) {
-            Spacer(Modifier.width(8.dp))
-            GsIconBox(
-                onClick = { CallPrompt.ask(placeName.ifBlank { number!! }, number!!) },
-                colors = GsColors(MaterialTheme.colorScheme.primary, MaterialTheme.colorScheme.onPrimary),
-                shape = RoundedCornerShape(24.dp),
-            ) {
-                Row(Modifier.padding(horizontal = 16.dp, vertical = 10.dp), verticalAlignment = Alignment.CenterVertically) {
-                    androidx.compose.material3.Icon(Icons.Filled.Call, null, Modifier.size(20.dp))
-                    Spacer(Modifier.width(6.dp))
-                    Text("Call", style = ChromeType.body)
-                }
-            }
-        }
-        ActionRow(row.actions.orEmpty())
-    }
-}
-
-/** A line that is only a phone number: digits with the usual separators, 7 to 15 digits long. */
-private fun String.isPhoneNumber(): Boolean {
-    val t = trim()
-    if (!Regex("""^\+?[0-9 ().\-]+$""").matches(t)) return false
-    return t.count { it.isDigit() } in 7..15
-}
-
-@Composable
-internal fun RowItem(row: CarRow, selection: RowSelection? = null, large: Boolean = false) {
-    val toggle = row.toggle
-    // Shown at once and corrected when the app answers with its own template, so the switch
-    // never lags a tap; keyed on what the app last said so its answer wins.
-    var checked by remember(toggle?.isChecked) { mutableStateOf(toggle?.isChecked == true) }
-    val clickable = row.isEnabled && (toggle != null || selection != null || row.onClickDelegate != null)
-    Row(
-        Modifier
-            .fillMaxWidth()
-            .let {
-                if (!clickable) it else it.clickable {
-                    when {
-                        toggle != null -> {
-                            checked = !checked
-                            toggle.onCheckedChangeDelegate.checkedChanged(checked)
-                        }
-                        selection != null -> selection.onPick()
-                        else -> row.onClickDelegate.click("row")
-                    }
-                }
-            }
-            .padding(horizontal = 14.dp, vertical = 10.dp),
-        verticalAlignment = Alignment.CenterVertically,
-    ) {
-        if (selection != null) {
-            RadioButton(selected = selection.selected, onClick = null)
-            Spacer(Modifier.width(12.dp))
-        }
-        row.image?.let {
-            CarGlyph(it, Modifier.size(28.dp))
-            Spacer(Modifier.width(12.dp))
-        }
-        // large only changes how much room a row gets (more lines, a bigger icon above) - the
-        // type itself is the same scale as every other row, so a pane's one row and a plain
-        // list's tenth row read as the same kind of text.
-        Column(Modifier.weight(1f)) {
-            Text(
-                row.title.text(),
-                style = ChromeType.title,
-                maxLines = if (large) 2 else 1,
-                overflow = TextOverflow.Ellipsis,
-            )
-            row.texts.orEmpty().take(if (large) 3 else 2).forEach { line ->
-                Text(
-                    line.text(),
-                    style = ChromeType.body,
-                    color = MaterialTheme.colorScheme.onSurfaceVariant,
-                    maxLines = if (large) 2 else 1,
-                    overflow = TextOverflow.Ellipsis,
-                )
-            }
-        }
-        ActionRow(row.actions.orEmpty())
-        if (toggle != null) {
-            Spacer(Modifier.width(8.dp))
-            Switch(checked = checked, onCheckedChange = null, enabled = row.isEnabled)
-        }
-    }
-}
-
-/** A row's place in a single-choice list: whether it is the chosen one, and what picking it does. */
-internal class RowSelection(val selected: Boolean, val onPick: () -> Unit)
-
-/**
- * Whether this colour stands out against the background that [content] was chosen for: at least
- * 3:1, the WCAG minimum for icons. The background is taken as the opposite of the content colour.
- */
-private fun Color.readableOn(content: Color): Boolean {
-    val background = if (content.luminanceIsDark()) Color.White else Color(0xFF121212)
-    val a = luminance() + 0.05f
-    val b = background.luminance() + 0.05f
-    return maxOf(a, b) / minOf(a, b) >= 3f
-}
-
 internal fun Color.luminanceIsDark(): Boolean =
     (red * 0.299f + green * 0.587f + blue * 0.114f) < 0.5f
 

gearslip/src/main/java/app/seb3thehacker/gearslip/car/TemplateRows.kt

@@ -0,0 +1,391 @@
+package app.seb3thehacker.gearslip.car
+
+import app.seb3thehacker.gearslip.car.theme.*
+import androidx.compose.runtime.produceState
+import androidx.compose.runtime.remember
+import androidx.compose.ui.focus.onFocusChanged
+import androidx.compose.material3.LocalContentColor
+import androidx.compose.ui.graphics.ColorFilter
+import androidx.compose.ui.graphics.luminance
+import androidx.compose.ui.graphics.ImageBitmap
+import androidx.compose.foundation.Image
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.grid.GridCells
+import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
+import androidx.compose.foundation.lazy.grid.items
+import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Call
+import androidx.compose.material.icons.filled.ArrowBack
+import androidx.compose.material.icons.filled.Menu
+import androidx.compose.material.icons.filled.Warning
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import app.seb3thehacker.gearslip.host.selected
+import app.seb3thehacker.gearslip.host.checkedChanged
+import androidx.compose.runtime.setValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.foundation.lazy.itemsIndexed
+import androidx.compose.material3.RadioButton
+import androidx.compose.material3.Switch
+import androidx.core.graphics.drawable.toBitmap
+import androidx.compose.ui.graphics.asImageBitmap
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.input.pointer.PointerEventPass
+import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.draw.alpha
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.Shape
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import androidx.car.app.model.Action
+import androidx.car.app.model.ActionStrip
+import androidx.car.app.model.CarIcon
+import androidx.car.app.model.GridItem
+import androidx.car.app.model.Header
+import androidx.car.app.model.ItemList
+import androidx.car.app.model.Pane
+import androidx.car.app.model.Row as CarRow
+import androidx.car.app.model.Template
+import app.seb3thehacker.gearslip.host.click
+import app.seb3thehacker.gearslip.host.color
+import app.seb3thehacker.gearslip.host.image
+import app.seb3thehacker.gearslip.host.isDrawable
+import app.seb3thehacker.gearslip.host.standardType
+import app.seb3thehacker.gearslip.host.text
+
+// Lists, grids, panes and rows of templated apps. Split out of TemplateParts.kt.
+
+@Composable
+internal fun PaneTitle(title: String) {
+    if (title.isEmpty()) return
+    Text(
+        title,
+        style = ChromeType.title,
+        modifier = Modifier.padding(horizontal = 14.dp, vertical = 10.dp),
+    )
+}
+
+@Composable
+internal fun ItemListColumn(
+    single: ItemList?,
+    sectioned: List<ItemList>? = null,
+    modifier: Modifier = Modifier,
+) {
+    val rows = buildList {
+        single?.items?.filterIsInstance<CarRow>()?.let(::addAll)
+        sectioned?.forEach { list -> addAll(list.items.filterIsInstance<CarRow>()) }
+    }
+    if (rows.isEmpty()) {
+        val message = single?.noItemsMessage.text()
+        if (message.isNotEmpty()) Text(message, Modifier.padding(14.dp), style = ChromeType.body)
+        return
+    }
+    // A list the app made selectable is a single-choice list: one option chosen, shown as a radio.
+    val onSelected = single?.onSelectedDelegate
+    val chosen = single?.selectedIndex ?: -1
+    LazyColumn(modifier, contentPadding = PaddingValues(bottom = 8.dp)) {
+        itemsIndexed(rows) { index, row ->
+            RowItem(row, onSelected?.let { RowSelection(index == chosen) { it.selected(index) } })
+        }
+    }
+}
+
+/** A grid of tappable tiles - what apps use for a home screen beside the map. Icons here are as
+ * often a small menu glyph (Organic Maps' Search, say) as real cover art, so the tile stays
+ * modest; [GridTile]'s own default is for the shelf case, where every tile is a photo. */
+@Composable
+internal fun GridItems(list: ItemList?, modifier: Modifier = Modifier) {
+    val items = list?.items?.filterIsInstance<GridItem>().orEmpty()
+    if (items.isEmpty()) return
+    LazyVerticalGrid(
+        columns = GridCells.Adaptive(84.dp),
+        modifier = modifier,
+        contentPadding = PaddingValues(horizontal = 8.dp, vertical = 4.dp),
+        horizontalArrangement = Arrangement.spacedBy(6.dp),
+        verticalArrangement = Arrangement.spacedBy(6.dp),
+    ) {
+        items(items) { item -> GridTile(item, iconSize = 36.dp) }
+    }
+}
+
+/**
+ * One cover-art tile: an app's own icon over a title and optional subtitle. Shared by
+ * [GridItems] (a whole screen of tiles, [iconSize] scaled down there to suit a plain menu glyph)
+ * and a section's horizontal shelf, which carries the same [GridItem] type but scrolls sideways
+ * instead of wrapping into a grid and wants its full-size cover art.
+ */
+@Composable
+internal fun GridTile(item: GridItem, modifier: Modifier = Modifier, iconSize: androidx.compose.ui.unit.Dp = 144.dp) {
+    Column(
+        modifier
+            .clickable { item.onClickDelegate.click("grid item") }
+            .padding(vertical = 8.dp),
+        horizontalAlignment = Alignment.CenterHorizontally,
+    ) {
+        CarGlyph(item.image, Modifier.size(iconSize))
+        Spacer(Modifier.height(6.dp))
+        Text(
+            item.title.text(),
+            style = ChromeType.label,
+            maxLines = 1,
+            overflow = TextOverflow.Ellipsis,
+        )
+        val subtitle = item.text.text()
+        if (subtitle.isNotEmpty()) {
+            Text(
+                subtitle,
+                style = ChromeType.label,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis,
+            )
+        }
+    }
+}
+
+/**
+ * [autoStart] is for a pane floating over a map - a place or a route the app is proposing - where
+ * a single action counts itself down rather than waiting to be pressed, on the theory that a
+ * driver glancing at the car screen has already decided. It never applies to more than one
+ * action: a pane offering a real choice (Start vs. something else) always waits to be tapped.
+ */
+@Composable
+internal fun PaneRows(pane: Pane?, modifier: Modifier = Modifier, autoStart: Boolean = false) {
+    // Some apps pad a pane with a row of blank strings; drawn, it is just a gap.
+    val rows = pane?.rows.orEmpty().filterNot { it.isBlank() }
+    val actions = pane?.actions.orEmpty().filter { it.isDrawable() }
+    val card = PlaceCard.of(rows)
+    Column(modifier) {
+        card.heading?.let { PlaceHeading(it) }
+        if (card.buttons.isNotEmpty()) RowButtons(card.buttons, Modifier.padding(horizontal = 14.dp, vertical = 6.dp))
+        if (autoStart && actions.size == 1) {
+            AutoStartButton(actions.single(), Modifier.padding(horizontal = 14.dp, vertical = 10.dp))
+        } else {
+            ActionRow(actions, Modifier.padding(horizontal = 14.dp, vertical = 10.dp), large = true)
+        }
+        if (card.heading == null && card.buttons.isEmpty()) {
+            card.details.forEach { RowItem(it, large = true) }
+        } else {
+            card.details.forEach { DetailRow(it, card.heading?.title?.text().orEmpty()) }
+        }
+    }
+}
+
+/**
+ * A pane split the way a place page reads: a name on top, the things to do with it as buttons,
+ * then the facts. Apps send all three as plain rows, so the split is worked out from the rows'
+ * shape alone. A pane that doesn't fit the shape - all of it tappable, like a menu - gets no
+ * heading and no buttons, and draws exactly as a plain list of rows.
+ */
+private class PlaceCard(val heading: CarRow?, val buttons: List<CarRow>, val details: List<CarRow>) {
+    companion object {
+        fun of(rows: List<CarRow>): PlaceCard {
+            // A short tappable row with an icon and nothing under it is a button in all but name:
+            // MAPS.ME's "Let's go" and "Save".
+            val buttons = rows.filter {
+                it.onClickDelegate != null && it.toggle == null && it.image != null &&
+                    it.texts.orEmpty().isEmpty() && it.title.text().length <= 24
+            }.takeIf { it.size in 1..4 && it.size < rows.size }.orEmpty()
+            // A first row that can't be tapped and has no icon is the place's name and kind.
+            val heading = rows.firstOrNull()?.takeIf {
+                buttons.isNotEmpty() && it.onClickDelegate == null && it.image == null && it.toggle == null
+            }
+            return PlaceCard(heading, buttons, rows - buttons.toSet() - listOfNotNull(heading).toSet())
+        }
+    }
+}
+
+@Composable
+private fun PlaceHeading(row: CarRow) {
+    Column(Modifier.fillMaxWidth().padding(horizontal = 14.dp, vertical = 6.dp)) {
+        Text(row.title.text(), style = ChromeType.title, maxLines = 2, overflow = TextOverflow.Ellipsis)
+        row.texts.orEmpty().take(2).forEach {
+            Text(it.text(), style = ChromeType.body, color = MaterialTheme.colorScheme.onSurfaceVariant, maxLines = 1, overflow = TextOverflow.Ellipsis)
+        }
+    }
+}
+
+/** Button-shaped rows side by side, the first one filled as the thing most drivers came to do. */
+@Composable
+private fun RowButtons(rows: List<CarRow>, modifier: Modifier) {
+    val scheme = MaterialTheme.colorScheme
+    Row(modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+        rows.forEachIndexed { i, row ->
+            GsIconBox(
+                onClick = { row.onClickDelegate.click("row") },
+                modifier = Modifier.weight(1f),
+                colors = if (i == 0) GsColors(scheme.primary, scheme.onPrimary) else GsColors(scheme.surfaceContainerHighest, scheme.onSurface),
+                enabled = row.isEnabled,
+                shape = RoundedCornerShape(24.dp),
+            ) {
+                Row(
+                    Modifier.fillMaxWidth().padding(horizontal = 16.dp, vertical = 14.dp),
+                    horizontalArrangement = Arrangement.Center,
+                    verticalAlignment = Alignment.CenterVertically,
+                ) {
+                    CarGlyph(row.image, Modifier.size(24.dp))
+                    Spacer(Modifier.width(8.dp))
+                    Text(row.title.text(), style = ChromeType.body, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                }
+            }
+        }
+    }
+}
+
+/**
+ * One fact about a place, tighter than a list row: a small label over its value, or just the
+ * value when the row has no label. A phone number gets a Call button that asks first.
+ */
+@Composable
+private fun DetailRow(row: CarRow, placeName: String) {
+    val context = LocalContext.current
+    val texts = row.texts.orEmpty().map { it.text() }.filter { it.isNotBlank() }
+    val label = row.title.text().takeIf { texts.isNotEmpty() }
+    val values = texts.ifEmpty { listOf(row.title.text()) }
+    val number = values.firstOrNull { it.isPhoneNumber() }
+    val canCall = number != null &&
+        context.checkSelfPermission(android.Manifest.permission.CALL_PHONE) == android.content.pm.PackageManager.PERMISSION_GRANTED
+    Row(
+        Modifier
+            .fillMaxWidth()
+            .let { if (row.onClickDelegate != null && row.isEnabled) it.clickable { row.onClickDelegate.click("row") } else it }
+            .padding(horizontal = 14.dp, vertical = 6.dp),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        row.image?.let {
+            CarGlyph(it, Modifier.size(24.dp))
+            Spacer(Modifier.width(12.dp))
+        }
+        Column(Modifier.weight(1f)) {
+            label?.let {
+                Text(it, style = MaterialTheme.typography.labelLarge, color = MaterialTheme.colorScheme.onSurfaceVariant, maxLines = 1)
+            }
+            values.take(3).forEach {
+                Text(it, style = ChromeType.body, maxLines = 2, overflow = TextOverflow.Ellipsis)
+            }
+        }
+        if (canCall) {
+            Spacer(Modifier.width(8.dp))
+            GsIconBox(
+                onClick = { CallPrompt.ask(placeName.ifBlank { number!! }, number!!) },
+                colors = GsColors(MaterialTheme.colorScheme.primary, MaterialTheme.colorScheme.onPrimary),
+                shape = RoundedCornerShape(24.dp),
+            ) {
+                Row(Modifier.padding(horizontal = 16.dp, vertical = 10.dp), verticalAlignment = Alignment.CenterVertically) {
+                    androidx.compose.material3.Icon(Icons.Filled.Call, null, Modifier.size(20.dp))
+                    Spacer(Modifier.width(6.dp))
+                    Text("Call", style = ChromeType.body)
+                }
+            }
+        }
+        ActionRow(row.actions.orEmpty())
+    }
+}
+
+/** A line that is only a phone number: digits with the usual separators, 7 to 15 digits long. */
+private fun String.isPhoneNumber(): Boolean {
+    val t = trim()
+    if (!Regex("""^\+?[0-9 ().\-]+$""").matches(t)) return false
+    return t.count { it.isDigit() } in 7..15
+}
+
+@Composable
+internal fun RowItem(row: CarRow, selection: RowSelection? = null, large: Boolean = false) {
+    val toggle = row.toggle
+    // Shown at once and corrected when the app answers with its own template, so the switch
+    // never lags a tap; keyed on what the app last said so its answer wins.
+    var checked by remember(toggle?.isChecked) { mutableStateOf(toggle?.isChecked == true) }
+    val clickable = row.isEnabled && (toggle != null || selection != null || row.onClickDelegate != null)
+    Row(
+        Modifier
+            .fillMaxWidth()
+            .let {
+                if (!clickable) it else it.clickable {
+                    when {
+                        toggle != null -> {
+                            checked = !checked
+                            toggle.onCheckedChangeDelegate.checkedChanged(checked)
+                        }
+                        selection != null -> selection.onPick()
+                        else -> row.onClickDelegate.click("row")
+                    }
+                }
+            }
+            .padding(horizontal = 14.dp, vertical = 10.dp),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        if (selection != null) {
+            RadioButton(selected = selection.selected, onClick = null)
+            Spacer(Modifier.width(12.dp))
+        }
+        row.image?.let {
+            CarGlyph(it, Modifier.size(28.dp))
+            Spacer(Modifier.width(12.dp))
+        }
+        // large only changes how much room a row gets (more lines, a bigger icon above) - the
+        // type itself is the same scale as every other row, so a pane's one row and a plain
+        // list's tenth row read as the same kind of text.
+        Column(Modifier.weight(1f)) {
+            Text(
+                row.title.text(),
+                style = ChromeType.title,
+                maxLines = if (large) 2 else 1,
+                overflow = TextOverflow.Ellipsis,
+            )
+            row.texts.orEmpty().take(if (large) 3 else 2).forEach { line ->
+                Text(
+                    line.text(),
+                    style = ChromeType.body,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    maxLines = if (large) 2 else 1,
+                    overflow = TextOverflow.Ellipsis,
+                )
+            }
+        }
+        ActionRow(row.actions.orEmpty())
+        if (toggle != null) {
+            Spacer(Modifier.width(8.dp))
+            Switch(checked = checked, onCheckedChange = null, enabled = row.isEnabled)
+        }
+    }
+}
+
+/** A row's place in a single-choice list: whether it is the chosen one, and what picking it does. */
+internal class RowSelection(val selected: Boolean, val onPick: () -> Unit)
+
+/**
+ * Whether this colour stands out against the background that [content] was chosen for: at least
+ * 3:1, the WCAG minimum for icons. The background is taken as the opposite of the content colour.
+ */
+internal fun Color.readableOn(content: Color): Boolean {
+    val background = if (content.luminanceIsDark()) Color.White else Color(0xFF121212)
+    val a = luminance() + 0.05f
+    val b = background.luminance() + 0.05f
+    return maxOf(a, b) / minOf(a, b) >= 3f
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/car/WebApp.kt

@@ -2,7 +2,14 @@ package app.seb3thehacker.gearslip.car
 
 import android.os.Handler
 import android.os.Looper
+import android.view.View
+import android.view.ViewGroup
 import android.webkit.JavascriptInterface
+import android.webkit.WebChromeClient
+import android.widget.FrameLayout
+import androidx.compose.foundation.layout.Box
+import androidx.compose.runtime.LaunchedEffect
+import app.seb3thehacker.gearslip.car.theme.GsIconButton
 import android.webkit.WebResourceError
 import android.webkit.WebResourceRequest
 import android.webkit.WebResourceResponse
@@ -24,6 +31,10 @@ import androidx.compose.ui.graphics.toArgb
 import androidx.compose.ui.viewinterop.AndroidView
 import app.seb3thehacker.gearslip.GearslipLog
 import org.json.JSONObject
+import androidx.compose.material.icons.filled.Search
+import androidx.compose.material.icons.filled.Refresh
+import androidx.compose.material.icons.filled.Home
+import androidx.compose.material.icons.automirrored.filled.ArrowForward
 
 /**
  * A browser inside the car UI. [content] is a URL, or raw HTML when it does not look like one.
@@ -43,11 +54,35 @@ fun WebApp(content: String) {
     val ring = String.format("#%06X", MaterialTheme.colorScheme.primary.toArgb() and 0xFFFFFF)
     var web by remember { mutableStateOf<WebView?>(null) }
     var fieldText by remember { mutableStateOf<String?>(null) }
+    // A page's own full screen, such as a video's: the view to show, and how to hand it back.
+    var pageFullscreen by remember { mutableStateOf<Pair<View, WebChromeClient.CustomViewCallback>?>(null) }
+    // Whether the video asked for full screen, rather than the driver from the header: ending
+    // the video's then leaves full screen too, instead of stranding them in it.
+    var videoMadeFullscreen by remember { mutableStateOf(false) }
+    val fullscreen = CarFullscreen.active
+    // What the header shows and what its buttons can do, refreshed as pages load.
+    var pageTitle by remember { mutableStateOf("") }
+    var canGoForward by remember { mutableStateOf(false) }
+    // The address being typed, or null while the header shows the page title.
+    var address by remember { mutableStateOf<String?>(null) }
+
+    // Leaving the browser ends full screen, whoever started it.
+    DisposableEffect(Unit) { onDispose { CarFullscreen.exit() } }
+    // The way out of full screen also ends the page's.
+    LaunchedEffect(fullscreen) {
+        if (!fullscreen) pageFullscreen?.let { (_, callback) ->
+            pageFullscreen = null
+            callback.onCustomViewHidden()
+        }
+    }
 
     DisposableEffect(web) {
         navigator.backInterceptor = {
             val view = web
-            if (view != null && view.canGoBack()) {
+            if (CarFullscreen.active) {
+                CarFullscreen.exit()
+                true
+            } else if (view != null && view.canGoBack()) {
                 view.goBack()
                 true
             } else {
@@ -59,25 +94,57 @@ fun WebApp(content: String) {
 
     Column(Modifier.fillMaxSize()) {
         // Back steps through the page's history first (the interceptor above), then leaves.
-        ScreenHeader("Browser", Modifier.padding(horizontal = 16.dp, vertical = 8.dp))
+        if (!fullscreen) {
+            ScreenHeader(pageTitle.ifEmpty { "Browser" }, Modifier.padding(horizontal = 16.dp, vertical = 8.dp)) {
+                GsIconButton(androidx.compose.material.icons.Icons.Filled.Search, "Search or type an address", {
+                    fieldText = null
+                    address = ""
+                })
+                if (canGoForward) {
+                    GsIconButton(androidx.compose.material.icons.Icons.AutoMirrored.Filled.ArrowForward, "Forward", { web?.goForward() })
+                }
+                GsIconButton(androidx.compose.material.icons.Icons.Filled.Refresh, "Reload", { web?.reload() })
+                GsIconButton(androidx.compose.material.icons.Icons.Filled.Home, "Start page", {
+                    web?.let { view -> loadContent(view, content) }
+                })
+                GsIconButton(MediaIcons.Fullscreen, "Full screen", CarFullscreen::enter)
+            }
+        }
+        Box(Modifier.weight(1f).fillMaxSize()) {
         AndroidView(
-            modifier = Modifier.weight(1f).fillMaxSize(),
+            modifier = Modifier.fillMaxSize(),
             factory = { context ->
                 WebView(context).apply {
                     settings.javaScriptEnabled = true
                     settings.domStorageEnabled = true
                     settings.loadWithOverviewMode = true
                     settings.useWideViewPort = true
-                    webViewClient = LoggingClient(ring)
+                    webViewClient = LoggingClient(ring) { view ->
+                        canGoForward = view.canGoForward()
+                        pageTitle = view.title.orEmpty().takeUnless { it.startsWith("http") || it == "about:blank" }.orEmpty()
+                    }
+                    webChromeClient = object : WebChromeClient() {
+                        override fun onReceivedTitle(view: WebView?, title: String?) {
+                            pageTitle = title.orEmpty().takeUnless { it.startsWith("http") || it == "about:blank" }.orEmpty()
+                        }
+
+                        override fun onShowCustomView(view: View, callback: CustomViewCallback) {
+                            videoMadeFullscreen = !CarFullscreen.active
+                            pageFullscreen = view to callback
+                            CarFullscreen.enter()
+                        }
+
+                        override fun onHideCustomView() {
+                            if (pageFullscreen == null) return
+                            pageFullscreen = null
+                            if (videoMadeFullscreen) CarFullscreen.exit()
+                        }
+                    }
                     addJavascriptInterface(
                         FieldFocusBridge(onFocus = { fieldText = it }, onBlur = { fieldText = null }),
                         "GearslipField",
                     )
-                    if (content.startsWith("http://") || content.startsWith("https://")) {
-                        loadUrl(content)
-                    } else {
-                        loadDataWithBaseURL(null, content, "text/html", "utf-8", null)
-                    }
+                    loadContent(this, content)
                     web = this
                 }
             },
@@ -85,6 +152,33 @@ fun WebApp(content: String) {
             update = { it.settings.isAlgorithmicDarkeningAllowed = darkOutside },
             onRelease = { it.destroy() },
         )
+        pageFullscreen?.let { (view, _) ->
+            androidx.compose.runtime.key(view) {
+                AndroidView(
+                    factory = { context ->
+                        FrameLayout(context).apply {
+                            setBackgroundColor(android.graphics.Color.BLACK)
+                            (view.parent as? ViewGroup)?.removeView(view)
+                            addView(view, FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT))
+                        }
+                    },
+                    modifier = Modifier.fillMaxSize(),
+                    onRelease = { it.removeAllViews() },
+                )
+            }
+        }
+        }
+        address?.let { typed ->
+            CarKeyboard(
+                text = typed,
+                onTextChange = { address = it },
+                onSubmit = {
+                    web?.loadUrl(addressToUrl(typed))
+                    address = null
+                },
+                onDismiss = { address = null },
+            )
+        }
         fieldText?.let { text ->
             CarKeyboard(
                 text = text,
@@ -102,9 +196,29 @@ fun WebApp(content: String) {
     }
 }
 
-private class LoggingClient(private val ring: String) : WebViewClient() {
+/** The start page: a web address, or a page of HTML Gearslip made itself. */
+private fun loadContent(view: WebView, content: String) {
+    if (content.startsWith("http://") || content.startsWith("https://")) {
+        view.loadUrl(content)
+    } else {
+        view.loadDataWithBaseURL(null, content, "text/html", "utf-8", null)
+    }
+}
+
+/** Something that looks like an address opens as one; anything else is searched for. */
+private fun addressToUrl(typed: String): String {
+    val text = typed.trim()
+    return when {
+        text.startsWith("http://") || text.startsWith("https://") -> text
+        ' ' !in text && '.' in text -> "https://$text"
+        else -> "https://duckduckgo.com/?q=" + java.net.URLEncoder.encode(text, "UTF-8")
+    }
+}
+
+private class LoggingClient(private val ring: String, private val onLoaded: (WebView) -> Unit) : WebViewClient() {
     override fun onPageFinished(view: WebView?, url: String?) {
         GearslipLog.i("car web page loaded: $url")
+        view?.let(onLoaded)
         view?.evaluateJavascript(FOCUS_TRACKING_JS, null)
         view?.evaluateJavascript(focusRingJs(ring), null)
     }

gearslip/src/main/java/app/seb3thehacker/gearslip/car/theme/CarColors.kt

@@ -0,0 +1,29 @@
+package app.seb3thehacker.gearslip.car.theme
+
+import androidx.compose.material3.ColorScheme
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.compositeOver
+
+/**
+ * The phone's Material You colours, with its accent washed over the surfaces. Material You's own
+ * surfaces are nearly neutral, which reads as flat grey on a car screen; tinting them with the
+ * phone's primary colour (purple on a purple phone) gives the whole UI the phone's hue, the way
+ * Material 3's surface tint does, and it changes with the wallpaper like everything else.
+ * Higher containers take more of the tint, so cards still stand off the background.
+ */
+fun ColorScheme.withTintedSurfaces(dark: Boolean): ColorScheme {
+    val base = if (dark) 0.03f else 0.02f
+    fun tint(own: Color, step: Int) = primary.copy(alpha = base + step * (if (dark) 0.015f else 0.01f)).compositeOver(own)
+    return copy(
+        background = tint(background, 0),
+        surface = tint(surface, 0),
+        surfaceDim = tint(surfaceDim, 0),
+        surfaceContainerLowest = tint(surfaceContainerLowest, 0),
+        surfaceContainerLow = tint(surfaceContainerLow, 1),
+        surfaceContainer = tint(surfaceContainer, 2),
+        surfaceContainerHigh = tint(surfaceContainerHigh, 3),
+        surfaceContainerHighest = tint(surfaceContainerHighest, 4),
+        surfaceBright = tint(surfaceBright, 4),
+        surfaceVariant = tint(surfaceVariant, 3),
+    )
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/host/CarAppCatalog.kt

@@ -13,6 +13,9 @@ class TemplateApp(
 ) {
     val isNavigation: Boolean get() = CarAppService.CATEGORY_NAVIGATION_APP in categories
 
+    /** A media car screen, or one that names no category (older media apps). */
+    val isMediaScreen: Boolean get() = kind == "media" || kind == "app"
+
     /** "navigation", "media", ... - what the app told the system it is. */
     val kind: String
         get() = categories.firstOrNull { it.startsWith(CATEGORY_PREFIX) }

gearslip/src/main/java/app/seb3thehacker/gearslip/host/CarAppConnection.kt

@@ -91,6 +91,9 @@ class CarAppConnection(private val context: Context) {
     private var navigationManager: INavigationManager? = null
     /** Main thread only, both of these - the handoff is a race between them either way round. */
     private var surfaceCallback: ISurfaceCallback? = null
+
+    /** Last visible and stable areas the UI reported, kept for the next surface. */
+    private var areas: Pair<Rect, Rect>? = null
     private var lent: Lent? = null
 
     private var binding: ServiceConnection? = null
@@ -223,6 +226,7 @@ class CarAppConnection(private val context: Context) {
     fun disconnect() = disconnect(keepLocation = false)
 
     private fun disconnect(keepLocation: Boolean) {
+        main.removeCallbacks(handshakeTimeout)
         clearToasts()
         lent?.let { sendSurfaceDestroyed(it) }
         lent = null
@@ -254,11 +258,24 @@ class CarAppConnection(private val context: Context) {
 
     // --- handshake ---------------------------------------------------------------------
 
+    /**
+     * An app that won't have Gearslip as its host never answers the first question. Car App
+     * Library 1.9 and later throw inside the app when a host that isn't Google's asks, and since
+     * the call is one-way the error never comes back, so without this the car would show
+     * "Starting..." for ever.
+     */
+    private val handshakeTimeout = Runnable {
+        if (_status.value.phase == Phase.HANDSHAKE) {
+            fail(Phase.REJECTED, "It didn't answer Gearslip. Apps built for newer versions of Android Auto only run on Google's.")
+        }
+    }
+
     private fun onBound(service: IBinder) {
         val app = ICarApp.Stub.asInterface(service)
         carApp = app
         update { it.copy(phase = Phase.HANDSHAKE, detail = "bound, asking for app info") }
         GearslipLog.i("host: bound; requesting app info")
+        main.postDelayed(handshakeTimeout, HANDSHAKE_TIMEOUT_MS)
 
         call("getAppInfo", onValue = { value ->
             val info = value as? AppInfo ?: return@call fail(Phase.FAILED, "app info was ${value?.javaClass?.simpleName}")
@@ -271,6 +288,7 @@ class CarAppConnection(private val context: Context) {
      * offers cannot be rendered correctly, so it is refused here rather than half-drawn.
      */
     private fun onAppInfo(info: AppInfo) {
+        main.removeCallbacks(handshakeTimeout)
         val negotiated = minOf(HOST_API_LEVEL, info.latestCarAppApiLevel)
         GearslipLog.i(
             "host: app api ${info.minCarAppApiLevel}..${info.latestCarAppApiLevel} " +
@@ -385,6 +403,8 @@ class CarAppConnection(private val context: Context) {
         // failure worth surfacing.
         runCatching {
             app.getManager(CarContext.NAVIGATION_SERVICE, object : IOnDoneCallback.Stub() {
+                // Car App Library 1.8 versions its host interfaces; each answers with the version it was built from.
+                override fun getInterfaceVersion(): Int = IOnDoneCallback.VERSION
                 override fun onSuccess(response: Bundleable?) {
                     val value = response?.let { runCatching { it.get() }.getOrNull() }
                     navigationManager = when (value) {
@@ -552,9 +572,11 @@ class CarAppConnection(private val context: Context) {
         // The app draws for the whole surface; the visible area is what isn't covered by host
         // chrome, and the stable area is the part that never gets covered. Both depend on the
         // template (see visibleAreaFor) and are reported by the UI via [reportAreas] once it
-        // has measured. Until then the whole surface is fair game.
+        // has measured. A fresh surface the same size keeps the last ones, since the UI only
+        // reports again when they change; until then the whole surface is fair game.
         val whole = Rect(0, 0, surface.width, surface.height)
-        reportAreas(whole, whole)
+        val last = areas?.takeIf { (visible, stable) -> whole.contains(visible) && whole.contains(stable) }
+        reportAreas(last?.first ?: whole, last?.second ?: whole)
 
         GearslipLog.i(
             "host: lent the app a ${surface.width}x${surface.height} @${surface.dpi}dpi surface"
@@ -575,6 +597,7 @@ class CarAppConnection(private val context: Context) {
 
     /** Tells the app which part of its surface the driver can actually see. */
     fun reportAreas(visible: Rect, stable: Rect) {
+        areas = visible to stable
         val callback = surfaceCallback ?: return
         runCatching { callback.onStableAreaChanged(stable, noop("onStableAreaChanged")) }
         runCatching { callback.onVisibleAreaChanged(visible, noop("onVisibleAreaChanged")) }
@@ -605,6 +628,7 @@ class CarAppConnection(private val context: Context) {
     // --- host interfaces the app calls back into -----------------------------------------
 
     private fun createAppHost(owner: Any) = object : IAppHost.Stub() {
+        override fun getInterfaceVersion(): Int = IAppHost.VERSION
         override fun invalidate() {
             GearslipLog.i("host: app invalidated its template")
             main.post { requestTemplate() }
@@ -643,6 +667,7 @@ class CarAppConnection(private val context: Context) {
     val trip: StateFlow<androidx.car.app.navigation.model.Trip?> = _trip.asStateFlow()
 
     private val navigationHost = object : INavigationHost.Stub() {
+        override fun getInterfaceVersion(): Int = INavigationHost.VERSION
         override fun navigationStarted() {
             GearslipLog.i("host: navigation started")
             navigating = true
@@ -670,6 +695,7 @@ class CarAppConnection(private val context: Context) {
      * IBinder must be a real IOnDoneCallback - the app dispatches the reply through it.
      */
     private val hardwareHost = object : ICarHardwareHost.Stub() {
+        override fun getInterfaceVersion(): Int = ICarHardwareHost.VERSION
         override fun getCarHardwareResult(
             type: Int,
             params: Bundleable?,
@@ -700,6 +726,7 @@ class CarAppConnection(private val context: Context) {
      * Library documents for a projected head unit; they are about the screen, not about us.
      */
     private val constraintHost = object : IConstraintHost.Stub() {
+        override fun getInterfaceVersion(): Int = IConstraintHost.VERSION
         override fun getContentLimit(type: Int): Int = when (type) {
             ConstraintManager.CONTENT_LIMIT_TYPE_GRID -> 12
             ConstraintManager.CONTENT_LIMIT_TYPE_PANE -> 4
@@ -718,10 +745,12 @@ class CarAppConnection(private val context: Context) {
      * that pushes suggestions shouldn't fail because its host doesn't surface them.
      */
     private val suggestionHost = object : ISuggestionHost.Stub() {
+        override fun getInterfaceVersion(): Int = ISuggestionHost.VERSION
         override fun updateSuggestions(suggestions: Bundleable?) = Unit
     }
 
     private fun createCarHost(owner: Any) = object : ICarHost.Stub() {
+        override fun getInterfaceVersion(): Int = ICarHost.VERSION
         private val appHost = createAppHost(owner)
 
         override fun getHost(type: String?): IBinder? = when (type) {
@@ -754,6 +783,7 @@ class CarAppConnection(private val context: Context) {
      */
     private fun call(name: String, onValue: (Any?) -> Unit, send: (IOnDoneCallback) -> Unit) {
         val callback = object : IOnDoneCallback.Stub() {
+            override fun getInterfaceVersion(): Int = IOnDoneCallback.VERSION
             override fun onSuccess(response: Bundleable?) {
                 val value = response?.let { runCatching { it.get() }.getOrNull() }
                 main.post { onValue(value) }
@@ -769,6 +799,7 @@ class CarAppConnection(private val context: Context) {
     }
 
     private fun noop(name: String) = object : IOnDoneCallback.Stub() {
+        override fun getInterfaceVersion(): Int = IOnDoneCallback.VERSION
         override fun onSuccess(response: Bundleable?) = Unit
         override fun onFailure(response: Bundleable?) = GearslipLog.w("host: $name failed")
     }
@@ -833,6 +864,9 @@ class CarAppConnection(private val context: Context) {
         /** How long a new destination waits for the old route to end; see [navigateTo]. */
         const val REROUTE_WAIT_MS = 1_500L
 
+        /** How long an app gets to answer the first question before it counts as refusing. */
+        const val HANDSHAKE_TIMEOUT_MS = 10_000L
+
         /** Context.BIND_FOREGROUND_SERVICE; the constant itself is hidden from the SDK. */
         const val BIND_FOREGROUND_SERVICE = 0x04000000
     }

gearslip/src/main/java/app/seb3thehacker/gearslip/host/CarModels.kt

@@ -31,7 +31,41 @@ import kotlin.math.roundToInt
  */
 
 /** The app's text, preferring the longest variant that will fit; variants are ordered longest first. */
-fun CarText?.text(): String = this?.takeIf { !it.isEmpty }?.toCharSequence()?.toString().orEmpty()
+fun CarText?.text(): String {
+    val chars = this?.takeIf { !it.isEmpty }?.toCharSequence() ?: return ""
+    return chars.withSpansFilledIn()
+}
+
+/**
+ * Apps write a route's time and length as spans over placeholder characters ("\u0000 · \u0000"
+ * with a DurationSpan and a DistanceSpan), leaving the host to format them. Plain toString()
+ * keeps only the placeholders, which is how a route option ended up reading "·".
+ */
+private fun CharSequence.withSpansFilledIn(): String {
+    if (this !is android.text.Spanned) return toString()
+    val spans = getSpans(0, length, androidx.car.app.model.CarSpan::class.java)
+        .filter { it is androidx.car.app.model.DurationSpan || it is androidx.car.app.model.DistanceSpan }
+        .sortedBy { getSpanStart(it) }
+    if (spans.isEmpty()) return toString()
+    val out = StringBuilder()
+    var at = 0
+    spans.forEach { span ->
+        val start = getSpanStart(span)
+        val end = getSpanEnd(span)
+        if (start < at || end > length) return@forEach
+        out.append(this, at, start)
+        out.append(
+            when (span) {
+                is androidx.car.app.model.DurationSpan -> remainingTime(span.durationSeconds)
+                is androidx.car.app.model.DistanceSpan -> span.distance.display()
+                else -> ""
+            },
+        )
+        at = end
+    }
+    out.append(this, at, length)
+    return out.toString().replace("\u0000", "").trim()
+}
 
 /**
  * Icons keep coming back under fresh [CarIcon]/IconCompat objects - every template refetch
@@ -53,7 +87,7 @@ private val iconCache = android.util.LruCache<String, ImageBitmap>(200)
 fun CarIcon?.image(context: Context): ImageBitmap? {
     val icon = this?.icon ?: return null
     val key = icon.cacheKey(context)
-    iconCache.get(key)?.let { return it }
+    key?.let { k -> iconCache.get(k)?.let { return it } }
     val drawable: Drawable = runCatching { icon.loadDrawable(context) }
         .onFailure { GearslipLog.w("icon: loadDrawable threw for ${icon.describe()}: ${it.javaClass.simpleName}: ${it.message}") }
         .getOrNull()
@@ -73,7 +107,7 @@ fun CarIcon?.image(context: Context): ImageBitmap? {
     val bitmap = runCatching { drawable.toBitmap(width, height).asImageBitmap() }
         .onFailure { GearslipLog.w("icon: toBitmap threw for ${icon.describe()}: ${it.javaClass.simpleName}: ${it.message}") }
         .getOrNull() ?: return null
-    iconCache.put(key, bitmap)
+    key?.let { iconCache.put(it, bitmap) }
     return bitmap
 }
 
@@ -83,7 +117,15 @@ fun CarIcon?.image(context: Context): ImageBitmap? {
  * so a cache keyed on the bare id kept drawing the old build's picture on the wrong button (Vela's
  * new Saved button came up as its search glyph).
  */
-private fun androidx.core.graphics.drawable.IconCompat.cacheKey(context: Context): String {
+/**
+ * Null for an icon that carries its own pixels: two different bitmaps describe the same, so a
+ * key would hand one app's turn arrow the picture of whatever bitmap was cached first.
+ */
+private fun androidx.core.graphics.drawable.IconCompat.cacheKey(context: Context): String? {
+    if (type == androidx.core.graphics.drawable.IconCompat.TYPE_BITMAP ||
+        type == androidx.core.graphics.drawable.IconCompat.TYPE_ADAPTIVE_BITMAP ||
+        type == androidx.core.graphics.drawable.IconCompat.TYPE_DATA
+    ) return null
     if (type != androidx.core.graphics.drawable.IconCompat.TYPE_RESOURCE) return describe()
     val installed = runCatching { context.packageManager.getPackageInfo(resPackage, 0).lastUpdateTime }.getOrDefault(0L)
     return "${describe()}@$installed"

gearslip/src/main/java/app/seb3thehacker/gearslip/host/KnownApps.kt

@@ -24,6 +24,7 @@ object KnownApps {
         "nl.flitsmeister", // Flitsmeister: map, routing, alerts - works well
         "com.mapquest.android.ace", // MapQuest: map, routing, navigation
         "com.mapswithme.maps.pro", // MAPS.ME: map, search, place pages, navigation
+        "app.vela", // Vela Maps: map, search, route options, turn-by-turn with lanes
     )
 
     fun works(packageName: String): Boolean = packageName in working
@@ -99,7 +100,6 @@ object KnownApps {
      * call working. Wins over [works] and [playerWorks] for the badge.
      */
     private val partial = setOf(
-        "app.vela", // Vela Maps: connects and draws, but rough enough not to call it working yet
         "com.spotify.music",        // Spotify: plays through Gearslip's player, but the app has to be opened on the phone first
         "deezer.android.app",       // Deezer: the same - it has to be opened on the phone first
     )

gearslip/src/main/java/app/seb3thehacker/gearslip/media/CarMediaStatus.kt

@@ -31,7 +31,7 @@ class CarMediaStatus(
     fun onMessage(messageId: Int, body: ByteArray) {
         when (messageId) {
             MSG_CHANNEL_OPEN_RESPONSE -> {
-                val status = Protobuf.readInt32Field(body, 1) ?: 0
+                val status = Protobuf.readInt32Field(body, 1)
                 GearslipLog.i("media status: <- ChannelOpenResponse: status=$status")
                 if (status == 0) start()
             }

gearslip/src/main/java/app/seb3thehacker/gearslip/protocol/InputProtocol.kt

@@ -0,0 +1,36 @@
+package app.seb3thehacker.gearslip.protocol
+
+import app.seb3thehacker.gearslip.TouchPoint
+import app.seb3thehacker.gearslip.Wire
+
+/** Decodes the touch coordinates and pointer index carried by an InputReport. */
+internal object InputProtocol {
+    data class Touch(val action: Int, val actionIndex: Int, val points: List<TouchPoint>)
+
+    /** [shiftX] and [shiftY] move each point by the margin the car crops off before measuring. */
+    fun touch(body: ByteArray, size: Pair<Int, Int>?, shiftX: Int = 0, shiftY: Int = 0): Touch? {
+        val fields = Wire.fields(body)
+        val action = Wire.varint(fields, 3)?.toInt() ?: 0
+        if (action !in setOf(0, 1, 2, 5, 6)) return null
+        val pointers = Wire.allBytes(fields, 1)
+        if (pointers.isEmpty() || pointers.size > 32) return null
+        val actionIndex = Wire.varint(fields, 2)?.toInt() ?: 0
+        if (actionIndex !in pointers.indices) return null
+        val points = pointers.map { pointer ->
+            val values = Wire.fields(pointer)
+            val x = Wire.varint(values, 1)?.toInt() ?: return null
+            val y = Wire.varint(values, 2)?.toInt() ?: return null
+            val id = Wire.varint(values, 3) ?: return null
+            if (id !in 0L..31L) return null
+            TouchPoint(id.toInt(), clamp(x + shiftX, size?.first), clamp(y + shiftY, size?.second))
+        }
+        if (points.map { it.id }.toSet().size != points.size) return null
+        return Touch(action, actionIndex, points)
+    }
+
+    private fun clamp(value: Int, limit: Int?): Float = when {
+        limit == null -> value.toFloat()
+        limit <= 0 -> 0f
+        else -> value.coerceIn(0, limit - 1).toFloat()
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/stats/UsageStats.kt

@@ -251,6 +251,17 @@ object UsageStats {
         if (c.phone) put("phone", "${Build.MANUFACTURER} ${Build.MODEL}")
     }
 
+    private var signerCache: String? = null
+
+    /** The first 16 hex digits of the SHA-256 of this APK's signing certificate. */
+    private fun signer(context: Context): String = signerCache ?: runCatching {
+        val cert = context.packageManager
+            .getPackageInfo(context.packageName, android.content.pm.PackageManager.GET_SIGNING_CERTIFICATES)
+            .signingInfo?.apkContentsSigners?.firstOrNull()?.toByteArray() ?: return@runCatching ""
+        java.security.MessageDigest.getInstance("SHA-256").digest(cert)
+            .take(8).joinToString("") { "%02x".format(it) }
+    }.getOrDefault("").also { signerCache = it }
+
     /**
      * What a note carries. With [everything], every field the driver shares, as Settings shows it;
      * otherwise exactly what the next note would send, which leaves out unchanged phone details.
@@ -263,6 +274,9 @@ object UsageStats {
             .put("version", BuildConfig.VERSION_NAME)
             .put("code", BuildConfig.VERSION_CODE)
             .put("build", if (BuildConfig.DEBUG) "debug" else "release")
+            // Who signed this copy, so a fork's builds can be told from Gearslip's own. Every copy
+            // from the same publisher sends the same value, so it says nothing about the phone.
+            .put("signer", signer(context))
             // Which boxes are ticked, so the server knows what this phone shares and can drop
             // anything it kept from a box since unticked.
             .put("shares", JSONArray().apply {

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/AboutLinks.kt

@@ -45,6 +45,9 @@ internal object GearslipLinks {
     const val SOURCE = "https://github.com/twinksoftware/gearslip"
     const val CARS = "$SOURCE/blob/main/CARS.md"
 
+    /** This version's release notes on GitHub; every release is tagged v plus its version name. */
+    val RELEASE_NOTES = "$SOURCE/releases/tag/v${app.seb3thehacker.gearslip.BuildConfig.VERSION_NAME}"
+
     fun open(context: Context, url: String) {
         runCatching {
             context.startActivity(Intent(Intent.ACTION_VIEW, Uri.parse(url)).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK))

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/CarPreviewScreen.kt

@@ -4,15 +4,8 @@ import android.app.Activity
 import android.content.Context
 import android.content.ContextWrapper
 import android.content.res.Configuration
-import android.graphics.Bitmap
-import android.graphics.PixelFormat
-import android.hardware.HardwareBuffer
-import android.media.ImageReader
-import android.os.Handler
-import android.os.Looper
 import android.view.MotionEvent
 import androidx.activity.compose.BackHandler
-import androidx.compose.foundation.Image
 import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.BoxScope
@@ -39,9 +32,7 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.graphics.asImageBitmap
 import androidx.compose.ui.input.pointer.pointerInteropFilter
-import androidx.compose.ui.layout.ContentScale
 import androidx.compose.ui.layout.onSizeChanged
 import androidx.compose.ui.platform.LocalConfiguration
 import androidx.compose.ui.platform.LocalContext
@@ -59,7 +50,7 @@ import app.seb3thehacker.gearslip.car.CarUi
  * Runs the real car UI on the bench and shows it on the phone.
  *
  * This is the same pipeline the car gets - a VirtualDisplay hosting a Presentation, driven by
- * the same [ScreenProjector] and fed the same touches - with an ImageReader standing in for the
+ * the same [ScreenProjector] and fed the same touches - with a SurfaceView standing in for the
  * H.264 encoder. That matters for anything composited rather than drawn by Compose, such as the
  * SurfaceView a templated app draws its map into: if it appears here, it will reach the car.
  *
@@ -69,49 +60,26 @@ import app.seb3thehacker.gearslip.car.CarUi
 fun CarPreviewScreen(onBack: () -> Unit) {
     val context = LocalContext.current
     val frame by CarEnvironment.frame.collectAsStateWithLifecycle()
-    var bitmap by remember { mutableStateOf<Bitmap?>(null) }
     var viewSize by remember { mutableStateOf(0 to 0) }
     // Tied to how the phone itself is held, not a button: turn it sideways and the preview goes
     // fullscreen, turn it back and the phone's own chrome (the Back/title above the frame) returns.
     val fullscreen = LocalConfiguration.current.orientation == Configuration.ORIENTATION_LANDSCAPE
 
-    val width = frame.width
-    val height = frame.height
-    val density = frame.densityDpi
+    val previewSize by app.seb3thehacker.gearslip.car.CarSettings.previewSize.collectAsStateWithLifecycle()
+    val custom by app.seb3thehacker.gearslip.car.CarSettings.previewCustom.collectAsStateWithLifecycle()
+    val (width, height, density) = previewFrame(context, frame, previewSize, custom)
 
     val projector = remember { ScreenProjector(context) }
 
     DisposableEffect(width, height, density) {
         CarEnvironment.start(context)
-
-        // COMPOSER_OVERLAY is what makes SurfaceFlinger willing to composite into this reader;
-        // CPU_READ_OFTEN is what makes the resulting buffer lockable, which is how the frame
-        // gets copied into a Bitmap. Without both, frames arrive but every copy fails.
-        val reader = ImageReader.newInstance(
-            width, height, PixelFormat.RGBA_8888, 3,
-            HardwareBuffer.USAGE_COMPOSER_OVERLAY or
-                HardwareBuffer.USAGE_GPU_SAMPLED_IMAGE or
-                HardwareBuffer.USAGE_CPU_READ_OFTEN,
-        )
-        val handler = Handler(Looper.getMainLooper())
-        reader.setOnImageAvailableListener({ source ->
-            val image = runCatching { source.acquireLatestImage() }.getOrNull() ?: return@setOnImageAvailableListener
-            try {
-                bitmap = image.toBitmap(width, height)
-            } catch (t: Throwable) {
-                GearslipLog.e("preview: could not copy a frame", t)
-            } finally {
-                image.close()
-            }
-        }, handler)
-
-        projector.start(reader.surface, width, height, density, name = "gearslip-preview") { CarUi() }
-
-        onDispose {
-            projector.stop()
-            reader.close()
-            bitmap = null
+        // No surface yet: the SurfaceView below hands its own over once it exists, and the
+        // display draws straight into it. Copying each frame into a Bitmap instead cost two
+        // full-size allocations per frame on the main thread, and taps lagged with the size.
+        projector.start(null, width, height, density, name = "gearslip-preview") {
+            androidx.compose.runtime.CompositionLocalProvider(app.seb3thehacker.gearslip.car.LocalCarPreview provides true) { CarUi() }
         }
+        onDispose { projector.stop() }
     }
 
     // The frame is drawn the same way in both layouts; only what surrounds it differs.
@@ -140,19 +108,32 @@ fun CarPreviewScreen(onBack: () -> Unit) {
                 },
             contentAlignment = Alignment.Center,
         ) {
-            bitmap?.let {
-                Image(
-                    it.asImageBitmap(),
-                    contentDescription = "Car screen",
+            androidx.compose.runtime.key(width, height) {
+                androidx.compose.ui.viewinterop.AndroidView(
+                    factory = { viewContext ->
+                        android.view.SurfaceView(viewContext).apply {
+                            // The car's own size; the compositor scales it to the view.
+                            holder.setFixedSize(width, height)
+                            holder.addCallback(object : android.view.SurfaceHolder.Callback {
+                                override fun surfaceCreated(holder: android.view.SurfaceHolder) =
+                                    projector.setSurface(holder.surface)
+
+                                override fun surfaceChanged(holder: android.view.SurfaceHolder, format: Int, w: Int, h: Int) =
+                                    projector.setSurface(holder.surface)
+
+                                override fun surfaceDestroyed(holder: android.view.SurfaceHolder) =
+                                    projector.setSurface(null)
+                            })
+                        }
+                    },
                     modifier = Modifier.fillMaxSize(),
-                    contentScale = ContentScale.Fit,
                 )
-            } ?: Text("Waiting for a frame…", color = Color.White)
+            }
         }
     }
 
     if (fullscreen) {
-        Fullscreen(onBack) {
+        Fullscreen(width.toFloat() / height, onBack) {
             // No fillMax here: left to the bounds alone, aspectRatio takes the whole width or the
             // whole height, whichever the car's shape allows, and the rest stays black.
             frameContent(Modifier)
@@ -192,6 +173,7 @@ fun CarPreviewScreen(onBack: () -> Unit) {
  */
 @Composable
 private fun Fullscreen(
+    aspect: Float,
     onBack: () -> Unit,
     content: @Composable BoxScope.() -> Unit,
 ) {
@@ -213,19 +195,31 @@ private fun Fullscreen(
     // is on and turning it sideways/back isn't an option.
     BackHandler(onBack = onBack)
 
-    Box(
+    androidx.compose.foundation.layout.BoxWithConstraints(
         Modifier.fillMaxSize().background(Color.Black),
         contentAlignment = Alignment.Center,
     ) {
         content()
 
         // The frame swallows every touch inside it, so leaving needs either the back gesture or
-        // a button of its own. This one sits in the corner the car UI leaves emptiest.
-        FilledTonalIconButton(
-            onClick = onBack,
-            modifier = Modifier.align(Alignment.BottomStart).padding(8.dp),
-        ) {
-            Icon(Icons.Filled.Close, contentDescription = "Leave the car preview")
+        // a button of its own. The button goes in the black beside the frame, never on it: over
+        // the frame it covered the car's own buttons. A frame the screen's own shape leaves no
+        // room, and then the back gesture is the way out.
+        val frameWidth = minOf(maxWidth, maxHeight * aspect)
+        val frameHeight = minOf(maxHeight, maxWidth / aspect)
+        val room = 56.dp
+        val corner = when {
+            maxWidth - frameWidth >= room * 2 -> Alignment.BottomStart
+            maxHeight - frameHeight >= room * 2 -> Alignment.TopStart
+            else -> null
+        }
+        if (corner != null) {
+            FilledTonalIconButton(
+                onClick = onBack,
+                modifier = Modifier.align(corner).padding(8.dp),
+            ) {
+                Icon(Icons.Filled.Close, contentDescription = "Leave the car preview")
+            }
         }
     }
 }
@@ -250,14 +244,26 @@ private fun Int.toCarAction(): Int = when (this) {
  * Copies one frame out of the reader. The reader's rows are padded to a hardware-friendly
  * stride, so the copy is made at the padded width and then cropped back.
  */
-private fun android.media.Image.toBitmap(width: Int, height: Int): Bitmap {
-    val plane = planes[0]
-    val pixelStride = plane.pixelStride
-    val rowPadding = plane.rowStride - pixelStride * width
-    val padded = Bitmap.createBitmap(
-        width + rowPadding / pixelStride, height, Bitmap.Config.ARGB_8888,
-    )
-    padded.copyPixelsFromBuffer(plane.buffer)
-    return if (padded.width == width) padded
-    else Bitmap.createBitmap(padded, 0, 0, width, height).also { padded.recycle() }
+/**
+ * The size the preview draws at. The last car's frame by default; this device's whole screen,
+ * for a head unit running Gearslip on its own (issue #12); or a size typed into Settings. The
+ * two new ones get a car-like density: 160dpi for every 480 pixels of height.
+ */
+private fun previewFrame(
+    context: android.content.Context,
+    lastCar: CarEnvironment.Frame,
+    size: app.seb3thehacker.gearslip.car.PreviewSize,
+    custom: app.seb3thehacker.gearslip.car.ScreenSize?,
+): Triple<Int, Int, Int> {
+    fun carLike(w: Int, h: Int) = Triple(w, h, (160 * h / 480).coerceIn(120, 640))
+    return when (size) {
+        app.seb3thehacker.gearslip.car.PreviewSize.LAST_CAR -> Triple(lastCar.width, lastCar.height, lastCar.densityDpi)
+        app.seb3thehacker.gearslip.car.PreviewSize.CUSTOM ->
+            custom?.let { carLike(it.width, it.height) } ?: Triple(lastCar.width, lastCar.height, lastCar.densityDpi)
+        app.seb3thehacker.gearslip.car.PreviewSize.FILL -> {
+            val bounds = context.getSystemService(android.view.WindowManager::class.java).maximumWindowMetrics.bounds
+            // Landscape, whichever way the device is held right now.
+            carLike(maxOf(bounds.width(), bounds.height()) / 2 * 2, minOf(bounds.width(), bounds.height()) / 2 * 2)
+        }
+    }
 }

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/CarScreenSettings.kt

@@ -0,0 +1,158 @@
+package app.seb3thehacker.gearslip.ui
+
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.selection.selectable
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.RadioButton
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.semantics.Role
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.unit.dp
+import app.seb3thehacker.gearslip.car.CarSettings
+import app.seb3thehacker.gearslip.car.PreviewSize
+import app.seb3thehacker.gearslip.car.ScreenFit
+import app.seb3thehacker.gearslip.car.ScreenSize
+
+/**
+ * The car screen's real size, for a head unit that reports the wrong one and stretches the
+ * picture, and the size the phone's car preview draws at. The same screen size and fit are in
+ * the car's own Settings; typing in any size is only here.
+ */
+@Composable
+internal fun CarScreenSection() {
+    val size by CarSettings.screenSize.collectAsState()
+    val fit by CarSettings.screenFit.collectAsState()
+    val preview by CarSettings.previewSize.collectAsState()
+    val previewCustom by CarSettings.previewCustom.collectAsState()
+    var editingCar by remember { mutableStateOf(false) }
+    var editingPreview by remember { mutableStateOf(false) }
+
+    if (editingCar) {
+        SizeDialog(
+            title = "Car screen size",
+            note = "Use this if the car's picture looks stretched. Enter the screen's real size, " +
+                "such as 1280x480. It takes effect the next time you connect.",
+            initial = size,
+            clearLabel = "Use the car's",
+            onDismiss = { editingCar = false },
+            onSave = { CarSettings.setScreenSize(it); editingCar = false },
+        )
+    }
+    if (editingPreview) {
+        SizeDialog(
+            title = "Preview size",
+            note = "The size the car preview draws at, such as 1920x720.",
+            initial = previewCustom,
+            clearLabel = null,
+            onDismiss = { editingPreview = false },
+            onSave = { custom ->
+                CarSettings.setPreviewSize(if (custom == null) PreviewSize.LAST_CAR else PreviewSize.CUSTOM, custom)
+                editingPreview = false
+            },
+        )
+    }
+
+    SettingsSection(
+        "Car screen",
+        footer = "Gearslip uses the size the car reports unless you set one.",
+    ) {
+        SettingsRow(
+            "Screen size",
+            Modifier.clickable { editingCar = true },
+            subtitle = size?.let { "$it, set by you" } ?: "From the car",
+        )
+        if (size != null) {
+            SettingsDivider()
+            SettingsRow(
+                "Crop the edges",
+                Modifier.selectable(fit == ScreenFit.CROP, role = Role.RadioButton) { CarSettings.setScreenFit(ScreenFit.CROP) },
+                subtitle = "For a car that cuts off the top and bottom, or the sides",
+                trailing = { RadioButton(selected = fit == ScreenFit.CROP, onClick = null) },
+            )
+            SettingsDivider()
+            SettingsRow(
+                "Squash to fit",
+                Modifier.selectable(fit == ScreenFit.SQUASH, role = Role.RadioButton) { CarSettings.setScreenFit(ScreenFit.SQUASH) },
+                subtitle = "For a car that squeezes the whole picture, so circles look like ovals",
+                trailing = { RadioButton(selected = fit == ScreenFit.SQUASH, onClick = null) },
+            )
+        }
+    }
+
+    SettingsSection("Car preview size") {
+        SettingsRow(
+            "Last car",
+            Modifier.selectable(preview == PreviewSize.LAST_CAR, role = Role.RadioButton) {
+                CarSettings.setPreviewSize(PreviewSize.LAST_CAR)
+            },
+            subtitle = "The size of the last car you connected to",
+            trailing = { RadioButton(selected = preview == PreviewSize.LAST_CAR, onClick = null) },
+        )
+        SettingsDivider()
+        SettingsRow(
+            "This screen",
+            Modifier.selectable(preview == PreviewSize.FILL, role = Role.RadioButton) {
+                CarSettings.setPreviewSize(PreviewSize.FILL)
+            },
+            subtitle = "Fills this device's screen, for a head unit running Gearslip itself",
+            trailing = { RadioButton(selected = preview == PreviewSize.FILL, onClick = null) },
+        )
+        SettingsDivider()
+        SettingsRow(
+            "Custom",
+            Modifier.selectable(preview == PreviewSize.CUSTOM, role = Role.RadioButton) {
+                if (previewCustom == null) editingPreview = true else CarSettings.setPreviewSize(PreviewSize.CUSTOM)
+            },
+            subtitle = previewCustom?.toString() ?: "Enter a size",
+            trailing = { RadioButton(selected = preview == PreviewSize.CUSTOM, onClick = null) },
+        )
+        if (preview == PreviewSize.CUSTOM) {
+            SettingsDivider()
+            SettingsRow("Change the custom size", Modifier.clickable { editingPreview = true })
+        }
+    }
+}
+
+/** Asks for a width and height; [clearLabel], when given, offers going back to no size at all. */
+@Composable
+private fun SizeDialog(
+    title: String,
+    note: String,
+    initial: ScreenSize?,
+    clearLabel: String?,
+    onDismiss: () -> Unit,
+    onSave: (ScreenSize?) -> Unit,
+) {
+    var width by remember { mutableStateOf(initial?.width?.toString().orEmpty()) }
+    var height by remember { mutableStateOf(initial?.height?.toString().orEmpty()) }
+    val parsed = ScreenSize.parse("${width}x$height")
+    val number = KeyboardOptions(keyboardType = KeyboardType.Number)
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = { Text(title) },
+        text = {
+            Column(verticalArrangement = Arrangement.spacedBy(12.dp)) {
+                Text(note)
+                OutlinedTextField(width, { width = it.filter(Char::isDigit) }, label = { Text("Width") }, singleLine = true, keyboardOptions = number)
+                OutlinedTextField(height, { height = it.filter(Char::isDigit) }, label = { Text("Height") }, singleLine = true, keyboardOptions = number)
+            }
+        },
+        confirmButton = { TextButton(onClick = { onSave(parsed) }, enabled = parsed != null) { Text("Save") } },
+        dismissButton = {
+            if (clearLabel != null) TextButton(onClick = { onSave(null) }) { Text(clearLabel) }
+            else TextButton(onClick = onDismiss) { Text("Cancel") }
+        },
+    )
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/GearslipApp.kt

@@ -37,7 +37,7 @@ import app.seb3thehacker.gearslip.BuildConfig
 import app.seb3thehacker.gearslip.CertProvider
 import app.seb3thehacker.gearslip.stats.UsageStats
 
-private enum class Screen { INTRO, HOME, LOGS, SETTINGS, CAR_PREVIEW, CERT_SETUP, SETUP_GUIDE, USAGE_NOTES, HELP, WHATS_NEW, RECOMMENDED_APPS }
+private enum class Screen { HOME, LOGS, SETTINGS, CAR_PREVIEW, CERT_SETUP, SETUP_GUIDE, USAGE_NOTES, HELP, WHATS_NEW, RECOMMENDED_APPS, CAR_GROUP }
 
 /** Three screens and a back stack of depth one: no navigation library needed. */
 @Composable
@@ -47,8 +47,8 @@ fun GearslipApp(onDisconnect: () -> Unit, onRequestCallScreening: () -> Unit) {
         !AppSettings.hasSkippedCertSetup(context) && !CertProvider.hasAnyCert(context)
     }
     val needsSetupGuide = remember { !AppSettings.hasSeenPermissionsSetup(context) }
-    // Where launch goes once the intro (if any) is done.
-    val afterIntro = remember {
+    // Where launch goes: setup until it's done, then Home.
+    val start = remember {
         when {
             needsCertSetup -> Screen.CERT_SETUP
             needsSetupGuide -> Screen.SETUP_GUIDE
@@ -57,14 +57,14 @@ fun GearslipApp(onDisconnect: () -> Unit, onRequestCallScreening: () -> Unit) {
             else -> Screen.HOME
         }
     }
-    var screen by rememberSaveable { mutableStateOf(if (Intro.due(context)) Screen.INTRO else afterIntro) }
-    // A replay from About goes back to Settings; the launch one carries on into setup.
-    var introReturn by rememberSaveable { mutableStateOf(afterIntro) }
+    var screen by rememberSaveable { mutableStateOf(start) }
     // Home's "it worked" card opens Settings at usage notes rather than at the top.
     var settingsAtUsageNotes by rememberSaveable { mutableStateOf(false) }
     // What's new and Connection help open from Home and from Settings; back returns to whichever.
     var backTo by rememberSaveable { mutableStateOf(Screen.SETTINGS) }
-    BackHandler(enabled = screen != Screen.HOME && screen != Screen.INTRO) {
+    // Which of the car's setting groups Home opened.
+    var carGroup by rememberSaveable { mutableStateOf(CarGroup.SCREEN) }
+    BackHandler(enabled = screen != Screen.HOME) {
         screen = when (screen) {
             Screen.RECOMMENDED_APPS, Screen.LOGS, Screen.CAR_PREVIEW -> Screen.SETTINGS
             Screen.HELP, Screen.WHATS_NEW -> backTo
@@ -101,33 +101,30 @@ fun GearslipApp(onDisconnect: () -> Unit, onRequestCallScreening: () -> Unit) {
             .windowInsetsPadding(WindowInsets.statusBars)
             .consumeWindowInsets(WindowInsets.statusBars),
     ) {
-        if (BuildConfig.DEBUG && screen != Screen.CAR_PREVIEW && screen != Screen.INTRO) DebugBuildBanner()
+        if (BuildConfig.DEBUG && screen != Screen.CAR_PREVIEW) DebugBuildBanner()
 
         Column(Modifier.weight(1f)) {
             when (screen) {
-                Screen.INTRO -> IntroScreen(onDone = { screen = introReturn })
                 Screen.HOME -> HomeScreen(
                     onOpenSettings = { settingsAtUsageNotes = false; screen = Screen.SETTINGS },
-                    onOpenWhatsNew = { backTo = Screen.HOME; screen = Screen.WHATS_NEW },
                     onOpenHelp = { backTo = Screen.HOME; screen = Screen.HELP },
                     onOpenUsageNotes = { settingsAtUsageNotes = true; screen = Screen.SETTINGS },
+                    onOpenCarPreview = { backTo = Screen.HOME; screen = Screen.CAR_PREVIEW },
+                    onOpenLogs = { backTo = Screen.HOME; screen = Screen.LOGS },
                     onDisconnect = onDisconnect,
+                    onOpenCarGroup = { carGroup = it; screen = Screen.CAR_GROUP },
                 )
+                Screen.CAR_GROUP -> CarGroupScreen(carGroup, onBack = { screen = Screen.HOME })
                 Screen.WHATS_NEW -> WhatsNewScreen(onBack = { screen = backTo })
-                Screen.LOGS -> LogsScreen(onBack = { screen = Screen.SETTINGS })
+                Screen.LOGS -> LogsScreen(onBack = { screen = backTo })
                 Screen.SETTINGS -> SettingsScreen(
                     onBack = { screen = Screen.HOME },
                     onOpenRecommendedApps = { settingsAtUsageNotes = false; screen = Screen.RECOMMENDED_APPS },
-                    onOpenWhatsNew = { settingsAtUsageNotes = false; backTo = Screen.SETTINGS; screen = Screen.WHATS_NEW },
-                    onOpenHelp = { settingsAtUsageNotes = false; backTo = Screen.SETTINGS; screen = Screen.HELP },
-                    onOpenCarPreview = { settingsAtUsageNotes = false; screen = Screen.CAR_PREVIEW },
-                    onOpenLogs = { settingsAtUsageNotes = false; screen = Screen.LOGS },
                     onReplayTutorial = { screen = Screen.SETUP_GUIDE },
-                    onReplayIntro = { Intro.replay(context); introReturn = Screen.SETTINGS; screen = Screen.INTRO },
                     atUsageNotes = settingsAtUsageNotes,
                 )
                 Screen.RECOMMENDED_APPS -> RecommendedAppsScreen(onBack = { screen = Screen.SETTINGS })
-                Screen.CAR_PREVIEW -> CarPreviewScreen(onBack = { screen = Screen.SETTINGS })
+                Screen.CAR_PREVIEW -> CarPreviewScreen(onBack = { screen = backTo })
                 Screen.HELP -> HelpScreen(
                     onBack = { screen = backTo },
                     onRequestCallScreening = onRequestCallScreening,
@@ -148,8 +145,9 @@ fun GearslipApp(onDisconnect: () -> Unit, onRequestCallScreening: () -> Unit) {
                 )
             }
         }
-        // A car keyboard is open: offer the phone's own, for a passenger.
-        if (screen != Screen.CAR_PREVIEW) PhoneTypingBar()
+        // A car keyboard is open: offer the phone's own, for a passenger. In the car preview it is
+        // the only keyboard, since the preview draws none of its own.
+        PhoneTypingBar()
     }
 }
 

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/GearslipTheme.kt

@@ -6,11 +6,16 @@ import androidx.compose.material3.dynamicDarkColorScheme
 import androidx.compose.material3.dynamicLightColorScheme
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.platform.LocalContext
+import app.seb3thehacker.gearslip.car.theme.withTintedSurfaces
 
-/** Material You: the palette comes from the wallpaper (minSdk 35, so dynamic color always exists). */
+/**
+ * Material You: the palette comes from the wallpaper (minSdk 35, so dynamic color always exists),
+ * with the same accent tint over the surfaces as the car screen, so the two look like one app.
+ */
 @Composable
 fun GearslipTheme(content: @Composable () -> Unit) {
     val context = LocalContext.current
-    val scheme = if (isSystemInDarkTheme()) dynamicDarkColorScheme(context) else dynamicLightColorScheme(context)
+    val dark = isSystemInDarkTheme()
+    val scheme = (if (dark) dynamicDarkColorScheme(context) else dynamicLightColorScheme(context)).withTintedSurfaces(dark)
     MaterialTheme(colorScheme = scheme, content = content)
 }

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/GuideParts.kt

@@ -0,0 +1,335 @@
+package app.seb3thehacker.gearslip.ui
+
+import androidx.compose.animation.core.Animatable
+import androidx.compose.animation.core.CubicBezierEasing
+import androidx.compose.animation.core.FastOutSlowInEasing
+import androidx.compose.animation.core.LinearEasing
+import androidx.compose.animation.core.RepeatMode
+import androidx.compose.animation.core.animateDpAsState
+import androidx.compose.animation.core.animateFloat
+import androidx.compose.animation.core.infiniteRepeatable
+import androidx.compose.animation.core.keyframes
+import androidx.compose.animation.core.rememberInfiniteTransition
+import androidx.compose.animation.core.tween
+import androidx.compose.foundation.Canvas
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.geometry.CornerRadius
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.geometry.Size
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.Path
+import androidx.compose.ui.graphics.StrokeCap
+import androidx.compose.ui.graphics.drawscope.DrawScope
+import androidx.compose.ui.graphics.drawscope.Stroke
+import androidx.compose.ui.graphics.drawscope.rotate
+import androidx.compose.ui.graphics.drawscope.scale
+import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.text.TextStyle
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.TextUnit
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.PlayArrow
+import androidx.compose.material.icons.filled.Search
+import androidx.compose.runtime.CompositionLocalProvider
+import app.seb3thehacker.gearslip.car.CarSettings
+import app.seb3thehacker.gearslip.car.theme.GsButton
+import app.seb3thehacker.gearslip.car.theme.GsIconButton
+import app.seb3thehacker.gearslip.car.theme.GsThemes
+import app.seb3thehacker.gearslip.car.theme.GsTone
+import app.seb3thehacker.gearslip.car.theme.LocalGsTheme
+import kotlin.math.PI
+import kotlin.math.cos
+import kotlin.math.atan2
+import kotlin.math.sqrt
+import kotlin.math.sin
+import kotlinx.coroutines.delay
+
+/**
+ * The setup guide's tones, taken from the phone's own Material You colours like the rest of the app.
+ * Every size is taken from the screen's width, so the guide scales from small phones to tablets.
+ */
+internal class IntroColors(
+    val surface: Color, val onSurface: Color, val onVariant: Color, val outline: Color,
+    val primary: Color, val onPrimary: Color, val primaryC: Color, val onPrimaryC: Color,
+    val tertiaryC: Color, val onTertiaryC: Color, val secondaryC: Color, val onSecondaryC: Color,
+)
+
+@Composable
+internal fun introColors(): IntroColors {
+    val m = MaterialTheme.colorScheme
+    return IntroColors(
+        surface = m.surface, onSurface = m.onSurface, onVariant = m.onSurfaceVariant, outline = m.outline,
+        primary = m.primary, onPrimary = m.onPrimary, primaryC = m.primaryContainer, onPrimaryC = m.onPrimaryContainer,
+        tertiaryC = m.tertiaryContainer, onTertiaryC = m.onTertiaryContainer,
+        secondaryC = m.secondaryContainer, onSecondaryC = m.onSecondaryContainer,
+    )
+}
+
+private val Pop = CubicBezierEasing(0.3f, 1.6f, 0.5f, 1f)
+private val Rise = CubicBezierEasing(0.2f, 0.8f, 0.2f, 1f)
+
+/** 0 to 1 once each time [key] changes, after [delayMs]: drives the entrance of one element. */
+@Composable
+internal fun entrance(key: Any, delayMs: Int, durationMs: Int = 650): Float {
+    val a = remember(key) { Animatable(0f) }
+    LaunchedEffect(key) {
+        delay(delayMs.toLong())
+        a.animateTo(1f, tween(durationMs, easing = LinearEasing))
+    }
+    return a.value
+}
+
+/** Slides up and fades in, like the mockup's `up`. */
+internal fun Modifier.up(p: Float, distance: Dp) = graphicsLayer {
+    val e = Rise.transform(p)
+    alpha = e
+    translationY = (1 - e) * distance.toPx()
+}
+
+/** Grows in with a bounce, like the mockup's `bounce`. */
+internal fun Modifier.pop(p: Float) = graphicsLayer {
+    val e = Pop.transform(p)
+    alpha = p.coerceAtMost(1f)
+    scaleX = 0.5f + 0.5f * e
+    scaleY = 0.5f + 0.5f * e
+}
+
+/**
+ * The car's button styles side by side, each drawn in its own style, and a row of real car
+ * controls below that redraws in whichever is picked. Picking saves it, so the car shows it too.
+ */
+@Composable
+internal fun ThemePicker(c: IntroColors, cq: (Float) -> Dp, cqSp: (Float) -> TextUnit, key: Any) {
+    val chosenId by CarSettings.uiTheme.collectAsState()
+    val chosen = GsThemes.byId(chosenId)
+    // Flat first: it's the default.
+    val themes = listOf(GsThemes.Flat) + GsThemes.builtIn.filter { it != GsThemes.Flat }
+    Column(
+        Modifier.padding(top = cq(7f)).fillMaxWidth().up(entrance(key, 500, 700), cq(7f)),
+        verticalArrangement = Arrangement.spacedBy(cq(6f)),
+    ) {
+        Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(cq(3f))) {
+            themes.forEach { theme ->
+                CompositionLocalProvider(LocalGsTheme provides theme) {
+                    GsButton(
+                        onClick = { CarSettings.setUiTheme(theme.id) },
+                        modifier = Modifier.weight(1f),
+                        tone = if (theme == chosen) GsTone.Primary else GsTone.Neutral,
+                        contentPadding = PaddingValues(horizontal = cq(1f), vertical = cq(3f)),
+                    ) {
+                        Text(
+                            if (theme == chosen) "✓ ${theme.name}" else theme.name,
+                            style = TextStyle(fontSize = cqSp(4.2f), fontWeight = FontWeight.Bold),
+                            maxLines = 1,
+                        )
+                    }
+                }
+            }
+        }
+        // What the car shows: the player's controls and a full-width action.
+        CompositionLocalProvider(LocalGsTheme provides chosen) {
+            Row(
+                Modifier.fillMaxWidth(),
+                horizontalArrangement = Arrangement.spacedBy(cq(3f)),
+                verticalAlignment = Alignment.CenterVertically,
+            ) {
+                GsIconButton(Icons.Filled.Search, "Search", onClick = {}, size = cq(15f), iconSize = cq(7f))
+                GsIconButton(Icons.Filled.PlayArrow, "Play", onClick = {}, tone = GsTone.Primary, size = cq(15f), iconSize = cq(8f))
+                GsButton(
+                    onClick = {},
+                    modifier = Modifier.weight(1f).height(cq(15f)),
+                    tone = GsTone.Tonal,
+                ) { Text("Navigate", style = TextStyle(fontSize = cqSp(4.6f), fontWeight = FontWeight.Bold)) }
+            }
+        }
+    }
+}
+
+/** Three keys of a keypad, pressing one after another. */
+@Composable
+internal fun ButtonsIcon(color: Color) {
+    val t by rememberInfiniteTransition(label = "keys").animateFloat(
+        0f, 3f, infiniteRepeatable(tween(2400, easing = LinearEasing)), label = "keys",
+    )
+    Canvas(Modifier.fillMaxSize()) {
+        inIconBox {
+            listOf(6f, 19f, 32f).forEachIndexed { i, x ->
+                // Each key dips for a moment while its turn comes round.
+                val dip = (1f - kotlin.math.abs(t - i - 0.5f) * 2f).coerceIn(0f, 1f) * 4f
+                drawRoundRect(color.copy(alpha = 0.45f), Offset(x, 16f + 4f), Size(10f, 16f),
+                    androidx.compose.ui.geometry.CornerRadius(3f))
+                drawRoundRect(color, Offset(x, 16f + dip), Size(10f, 16f), androidx.compose.ui.geometry.CornerRadius(3f))
+            }
+        }
+    }
+}
+
+/** Material's scalloped "cookie": a circle whose radius waves around its edge. */
+@Composable
+internal fun Cookie(color: Color, modifier: Modifier) {
+    Canvas(modifier) {
+        val unit = size.minDimension / 100f
+        val path = Path()
+        var deg = 0
+        while (deg <= 360) {
+            val a = deg * PI / 180
+            val r = (44 + 4.5 * cos(9 * a)) * unit
+            val x = center.x + (r * cos(a)).toFloat()
+            val y = center.y + (r * sin(a)).toFloat()
+            if (deg == 0) path.moveTo(x, y) else path.lineTo(x, y)
+            deg += 3
+        }
+        path.close()
+        drawPath(path, color)
+    }
+}
+
+/** Draws in the mockup's 48-unit icon box. */
+private inline fun DrawScope.inIconBox(block: DrawScope.() -> Unit) {
+    val s = size.minDimension / 48f
+    scale(s, s, Offset.Zero) { block() }
+}
+
+@Composable
+internal fun WifiIcon(color: Color) {
+    val t = rememberInfiniteTransition(label = "wifi")
+    val waves = (0..2).map { i ->
+        t.animateFloat(
+            0.35f, 1f,
+            infiniteRepeatable(tween(800, delayMillis = 0, easing = FastOutSlowInEasing), RepeatMode.Reverse,
+                initialStartOffset = androidx.compose.animation.core.StartOffset(i * 200)),
+            label = "wave$i",
+        )
+    }
+    Canvas(Modifier.fillMaxSize()) {
+        inIconBox {
+            val stroke = Stroke(5f, cap = StrokeCap.Round)
+            // The mockup's three arcs, inner to outer: radius r through (24 ± half, y).
+            listOf(Triple(8f, 6f, 34f), Triple(18f, 13f, 26f), Triple(28f, 20f, 18f)).forEachIndexed { i, (r, half, y) ->
+                val cy = y + sqrt(r * r - half * half)
+                val start = Math.toDegrees(atan2((y - cy).toDouble(), (-half).toDouble())).toFloat()
+                val end = Math.toDegrees(atan2((y - cy).toDouble(), half.toDouble())).toFloat()
+                drawArc(color.copy(alpha = waves[i].value), start, (end - start + 360f) % 360f, false,
+                    Offset(24f - r, cy - r), Size(2 * r, 2 * r), style = stroke)
+            }
+            drawCircle(color, 3.6f, Offset(24f, 41f))
+        }
+    }
+}
+
+@Composable
+internal fun MicIcon(color: Color) {
+    val t = rememberInfiniteTransition(label = "mic")
+    val waves = (0..1).map { i ->
+        t.animateFloat(
+            0.25f, 1f,
+            infiniteRepeatable(tween(700, easing = FastOutSlowInEasing), RepeatMode.Reverse,
+                initialStartOffset = androidx.compose.animation.core.StartOffset(i * 250)),
+            label = "mic$i",
+        )
+    }
+    Canvas(Modifier.fillMaxSize()) {
+        inIconBox {
+            drawRoundRect(color, Offset(18f, 5f), Size(12f, 22f), androidx.compose.ui.geometry.CornerRadius(6f))
+            val stroke = Stroke(4f, cap = StrokeCap.Round)
+            drawArc(color, 0f, 180f, false, Offset(12f, 14f), Size(24f, 22f), style = stroke)
+            drawLine(color, Offset(24f, 36f), Offset(24f, 42f), 4f, StrokeCap.Round)
+            // Sound waves either side, pulsing as if someone's talking.
+            listOf(1f to 0, -1f to 0, 1f to 1, -1f to 1).forEach { (side, i) ->
+                val r = if (i == 0) 15f else 21f
+                drawArc(color.copy(alpha = waves[i].value), if (side > 0) -35f else 145f, 70f, false,
+                    Offset(24f - r, 16f - r), Size(2 * r, 2 * r), style = stroke)
+            }
+        }
+    }
+}
+
+@Composable
+internal fun StarIcon(color: Color) {
+    val turn by rememberInfiniteTransition(label = "star").animateFloat(
+        -8f, 8f, infiniteRepeatable(tween(1600, easing = FastOutSlowInEasing), RepeatMode.Reverse), label = "star",
+    )
+    Canvas(Modifier.fillMaxSize()) {
+        inIconBox {
+            val star = Path()
+            for (i in 0 until 10) {
+                val r = if (i % 2 == 0) 20f else 8.5f
+                val a = (-90 + i * 36) * PI / 180
+                val x = 24f + (r * cos(a)).toFloat()
+                val y = 25f + (r * sin(a)).toFloat()
+                if (i == 0) star.moveTo(x, y) else star.lineTo(x, y)
+            }
+            star.close()
+            rotate(turn, Offset(24f, 25f)) { drawPath(star, color) }
+        }
+    }
+}
+
+@Composable
+internal fun HeartIcon(color: Color) {
+    val beat by rememberInfiniteTransition(label = "beat").animateFloat(
+        1f, 1f,
+        infiniteRepeatable(keyframes {
+            durationMillis = 1400
+            1f at 0; 1.16f at 210; 1f at 420; 1.1f at 630; 1f at 840
+        }),
+        label = "beat",
+    )
+    Canvas(Modifier.fillMaxSize()) {
+        inIconBox {
+            scale(beat, beat, Offset(24f, 24f)) {
+                val heart = Path().apply {
+                    moveTo(24f, 41f)
+                    cubicTo(10f, 31f, 5f, 23f, 5f, 16f)
+                    cubicTo(5f, 10f, 10f, 6f, 15f, 6f)
+                    cubicTo(19f, 6f, 22f, 8f, 24f, 12f)
+                    cubicTo(26f, 8f, 29f, 6f, 33f, 6f)
+                    cubicTo(38f, 6f, 43f, 10f, 43f, 16f)
+                    cubicTo(43f, 23f, 38f, 31f, 24f, 41f)
+                    close()
+                }
+                drawPath(heart, color)
+            }
+        }
+    }
+}
+
+@Composable
+internal fun Dots(c: IntroColors, count: Int, current: Int, cq: (Float) -> Dp, modifier: Modifier) {
+    Row(modifier, horizontalArrangement = Arrangement.spacedBy(cq(2f))) {
+        repeat(count) { i ->
+            val on = i == current
+            val width by animateDpAsState(if (on) cq(7f) else cq(2f), tween(300), label = "dot")
+            Box(
+                Modifier
+                    .size(width, cq(2f))
+                    .clip(RoundedCornerShape(50))
+                    .background(if (on) c.primary else c.outline.copy(alpha = 0.45f)),
+            )
+        }
+    }
+}
+

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/HomeCarSettings.kt

@@ -0,0 +1,245 @@
+package app.seb3thehacker.gearslip.ui
+
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.KeyboardArrowRight
+import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material3.DropdownMenu
+import androidx.compose.material3.DropdownMenuItem
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Switch
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+import app.seb3thehacker.gearslip.car.AppTheme
+import app.seb3thehacker.gearslip.car.CarApps
+import app.seb3thehacker.gearslip.car.CarSettings
+import app.seb3thehacker.gearslip.car.NavBarMode
+import app.seb3thehacker.gearslip.car.NightMode
+import app.seb3thehacker.gearslip.car.Units
+import app.seb3thehacker.gearslip.car.theme.GsThemes
+
+/** The car's setting groups, each opening its own screen from the phone's home screen. */
+enum class CarGroup(val title: String) {
+    SCREEN("Screen"),
+    NAV_BAR("Nav bar and player"),
+    SOUND("Sound and voice"),
+    WARNINGS("Warnings"),
+}
+
+private val sizeChoices = listOf(1f to "Normal", 1.25f to "Large", 1.5f to "Extra large")
+private val themeChoices = listOf(AppTheme.PHONE to "Follow phone", AppTheme.LIGHT to "Light", AppTheme.DARK to "Dark")
+private val nightChoices = listOf(NightMode.AUTO to "Auto", NightMode.DAY to "Day", NightMode.NIGHT to "Night")
+private val unitChoices = listOf(Units.AUTO to "Auto", Units.IMPERIAL to "Imperial", Units.METRIC to "Metric")
+private val navBarChoices = listOf(
+    NavBarMode.SHOW to "Always show",
+    NavBarMode.HIDE_NAVIGATING to "Hide while navigating",
+    NavBarMode.HIDE to "Hide until tapped",
+)
+private fun openChoices() = listOf(CarSettings.HOME to "Home") + CarApps.all.filter { it.id != "settings" }.map { it.id to it.label }
+
+/**
+ * The car's settings on the phone's home screen: one card per group with a summary of where it
+ * stands, each opening a screen of its own. They are the same settings as the car's own Settings
+ * app, so a change in either shows in both; the phone is just the easier place when parked.
+ */
+@Composable
+internal fun HomeCarSettings(onOpen: (CarGroup) -> Unit, modifier: Modifier = Modifier) {
+    val scale by CarSettings.scale.collectAsState()
+    val open by CarSettings.openOnConnect.collectAsState()
+    val navBar by CarSettings.navBarMode.collectAsState()
+    val pipeAudio by CarSettings.pipeAudio.collectAsState()
+    val speakDirections by CarSettings.speakDirections.collectAsState()
+    val bluetoothWarning by CarSettings.bluetoothWarning.collectAsState()
+    val locationWarning by CarSettings.locationWarning.collectAsState()
+    val playerLeft by CarSettings.playerLeft.collectAsState()
+    val theme by CarSettings.appTheme.collectAsState()
+
+    fun summary(group: CarGroup) = when (group) {
+        CarGroup.SCREEN -> listOf(openChoices().label(open), sizeChoices.label(scale), themeChoices.label(theme))
+        CarGroup.NAV_BAR -> listOf(navBarChoices.label(navBar), "Player on the ${if (playerLeft) "left" else "right"}")
+        CarGroup.SOUND -> listOf(if (pipeAudio) "USB audio" else "Bluetooth audio", "Directions ${if (speakDirections) "on" else "off"}")
+        CarGroup.WARNINGS -> listOf(
+            "Bluetooth ${if (bluetoothWarning && !pipeAudio) "on" else "off"}",
+            "Location ${if (locationWarning) "on" else "off"}",
+        )
+    }.filter { it.isNotEmpty() }.joinToString(" · ")
+
+    Column(modifier.fillMaxWidth(), verticalArrangement = Arrangement.spacedBy(12.dp)) {
+        Text(
+            "Car",
+            style = MaterialTheme.typography.headlineSmall,
+            fontWeight = FontWeight.Bold,
+            color = MaterialTheme.colorScheme.onBackground,
+            modifier = Modifier.padding(start = 4.dp),
+        )
+        SettingsCard {
+            CarGroup.entries.forEachIndexed { i, group ->
+                if (i > 0) SettingsDivider()
+                SettingsRow(
+                    group.title,
+                    Modifier.clickable { onOpen(group) },
+                    subtitle = summary(group),
+                    trailing = { Icon(Icons.AutoMirrored.Filled.KeyboardArrowRight, contentDescription = null) },
+                )
+            }
+        }
+    }
+}
+
+/** One group of the car's settings, on a screen of its own. */
+@OptIn(androidx.compose.material3.ExperimentalMaterial3Api::class)
+@Composable
+internal fun CarGroupScreen(group: CarGroup, onBack: () -> Unit) {
+    androidx.compose.material3.Scaffold(
+        containerColor = MaterialTheme.colorScheme.background,
+        topBar = {
+            androidx.compose.material3.TopAppBar(
+                title = { Text(group.title) },
+                navigationIcon = {
+                    androidx.compose.material3.IconButton(onClick = onBack) {
+                        Icon(Icons.AutoMirrored.Filled.ArrowBack, contentDescription = "Back")
+                    }
+                },
+            )
+        },
+    ) { padding ->
+        Column(
+            Modifier.fillMaxSize().padding(padding).padding(horizontal = 24.dp)
+                .verticalScroll(androidx.compose.foundation.rememberScrollState()),
+            verticalArrangement = Arrangement.spacedBy(16.dp),
+        ) {
+            SettingsCard { GroupRows(group) }
+            Text(
+                "These are the same settings as Settings in the car. A change here shows there too.",
+                style = MaterialTheme.typography.bodySmall,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                modifier = Modifier.padding(horizontal = 16.dp),
+            )
+        }
+    }
+}
+
+@Composable
+private fun GroupRows(group: CarGroup) {
+    val scale by CarSettings.scale.collectAsState()
+    val open by CarSettings.openOnConnect.collectAsState()
+    val night by CarSettings.nightMode.collectAsState()
+    val units by CarSettings.units.collectAsState()
+    val navBar by CarSettings.navBarMode.collectAsState()
+    val pipeAudio by CarSettings.pipeAudio.collectAsState()
+    val speakDirections by CarSettings.speakDirections.collectAsState()
+    val systemSpeech by CarSettings.systemSpeech.collectAsState()
+    val bluetoothWarning by CarSettings.bluetoothWarning.collectAsState()
+    val locationWarning by CarSettings.locationWarning.collectAsState()
+    val autoplay by CarSettings.autoplay.collectAsState()
+    val playerTitle by CarSettings.playerTitle.collectAsState()
+    val playerLeft by CarSettings.playerLeft.collectAsState()
+    val theme by CarSettings.appTheme.collectAsState()
+    val uiTheme by CarSettings.uiTheme.collectAsState()
+
+    when (group) {
+        CarGroup.SCREEN -> {
+            Choice("Open on connect", openChoices(), open, CarSettings::setOpenOnConnect)
+            SettingsDivider()
+            Choice("Size", sizeChoices, scale, CarSettings::setScale)
+            SettingsDivider()
+            Choice("App theme", themeChoices, theme, CarSettings::setAppTheme)
+            SettingsDivider()
+            Choice("Buttons", GsThemes.builtIn.map { it.id to it.name }, uiTheme, CarSettings::setUiTheme)
+            SettingsDivider()
+            Choice("Map day/night", nightChoices, night, CarSettings::setNightMode)
+            SettingsDivider()
+            Choice("Units", unitChoices, units, CarSettings::setUnits)
+        }
+        CarGroup.NAV_BAR -> {
+            Choice("Nav bar", navBarChoices, navBar, CarSettings::setNavBarMode)
+            SettingsDivider()
+            Choice("Player in the nav bar", listOf(false to "Skip buttons", true to "Song title"), playerTitle, CarSettings::setPlayerTitle)
+            SettingsDivider()
+            Choice("Player beside the map", listOf(false to "Right", true to "Left"), playerLeft, CarSettings::setPlayerLeft)
+            SettingsDivider()
+            Toggle("Autoplay on connect", autoplay, CarSettings::setAutoplay)
+        }
+        CarGroup.SOUND -> {
+            Choice("Car audio", listOf(false to "Bluetooth", true to "USB"), pipeAudio, CarSettings::setPipeAudio)
+            SettingsDivider()
+            Toggle(
+                "Spoken directions",
+                speakDirections,
+                CarSettings::setSpeakDirections,
+                note = "Turn it off if your map app's own voice already plays in the car.",
+            )
+            SettingsDivider()
+            Toggle(
+                "Use the phone's speech recognition",
+                systemSpeech,
+                CarSettings::setSystemSpeech,
+                note = "On most phones that's Google's, which may send your voice to Google.",
+            )
+        }
+        CarGroup.WARNINGS -> {
+            if (!pipeAudio) {
+                Toggle("Warn when Bluetooth isn't connected", bluetoothWarning, CarSettings::setBluetoothWarning)
+                SettingsDivider()
+            }
+            Toggle("Warn when location is off", locationWarning, CarSettings::setLocationWarning)
+        }
+    }
+}
+
+private fun <T> List<Pair<T, String>>.label(value: T): String = firstOrNull { it.first == value }?.second.orEmpty()
+
+/** A setting with a few named choices: its current one shown, the rest a tap away. */
+@Composable
+private fun <T> Choice(title: String, choices: List<Pair<T, String>>, selected: T, onSelect: (T) -> Unit) {
+    var menu by remember { mutableStateOf(false) }
+    SettingsRow(
+        title,
+        Modifier.clickable { menu = true },
+        trailing = {
+            // The menu hangs from the value it changes, at the row's end.
+            Box {
+                Text(choices.label(selected), style = MaterialTheme.typography.bodyLarge, color = MaterialTheme.colorScheme.primary)
+                DropdownMenu(menu, onDismissRequest = { menu = false }) {
+                    choices.forEach { (value, label) ->
+                        DropdownMenuItem(
+                            text = { Text(label, fontWeight = if (value == selected) FontWeight.Bold else FontWeight.Normal) },
+                            onClick = {
+                                onSelect(value)
+                                menu = false
+                            },
+                        )
+                    }
+                }
+            }
+        },
+    )
+}
+
+@Composable
+private fun Toggle(title: String, on: Boolean, onChange: (Boolean) -> Unit, note: String? = null) {
+    SettingsRow(
+        title,
+        Modifier.clickable { onChange(!on) },
+        subtitle = note,
+        trailing = { Switch(checked = on, onCheckedChange = null) },
+    )
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/HomeScreen.kt

@@ -5,6 +5,7 @@ import app.seb3thehacker.gearslip.speech.SpeechModels
 import androidx.compose.material3.LinearProgressIndicator
 
 import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.heightIn
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
@@ -27,6 +28,8 @@ import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.KeyboardArrowRight
+import androidx.compose.material.icons.automirrored.filled.List
+import androidx.compose.material.icons.automirrored.filled.Send
 import androidx.compose.material.icons.filled.Info
 import androidx.compose.material.icons.filled.Send
 import androidx.compose.material.icons.filled.List
@@ -60,10 +63,12 @@ import app.seb3thehacker.gearslip.stats.WorkedPrompt
 @Composable
 fun HomeScreen(
     onOpenSettings: () -> Unit,
-    onOpenWhatsNew: () -> Unit,
     onOpenHelp: () -> Unit,
     onOpenUsageNotes: () -> Unit,
+    onOpenCarPreview: () -> Unit,
+    onOpenLogs: () -> Unit,
     onDisconnect: () -> Unit,
+    onOpenCarGroup: (CarGroup) -> Unit,
 ) {
     val status by SessionStatus.state.collectAsStateWithLifecycle()
     val context = LocalContext.current
@@ -121,25 +126,18 @@ fun HomeScreen(
                     }
                     Spacer(Modifier.height(16.dp))
                     UpdateCard()
+                    Spacer(Modifier.height(24.dp))
+                    HomeCarSettings(onOpenCarGroup)
+                    Spacer(Modifier.height(16.dp))
                 }
 
                 // Sits at the bottom, where a thumb reaches it.
                 Column(Modifier.padding(vertical = 16.dp)) {
-                    SettingsCard {
-                        SettingsRow(
-                            "What's new in ${Intro.release}",
-                            Modifier.clickable(onClick = onOpenWhatsNew),
-                            icon = Icons.Filled.Star,
-                            trailing = { Arrow() },
-                        )
-                        SettingsDivider()
-                        SettingsRow(
-                            "Which cars work",
-                            Modifier.clickable(onClick = onOpenHelp),
-                            subtitle = "Most do. See which ones, and what to set up first",
-                            icon = Icons.Filled.Info,
-                            trailing = { Arrow() },
-                        )
+                    Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+                        HomeShortcut(Icons.Filled.Info, "Help", onOpenHelp, Modifier.weight(1f))
+                        // The preview draws the car screen on the phone, so it waits until no car is using it.
+                        if (!live) HomeShortcut(Icons.Filled.PlayArrow, "Preview", onOpenCarPreview, Modifier.weight(1f))
+                        HomeShortcut(Icons.AutoMirrored.Filled.List, "Logs", onOpenLogs, Modifier.weight(1f))
                     }
                     if (live) {
                         Spacer(Modifier.height(16.dp))
@@ -157,6 +155,27 @@ fun HomeScreen(
     }
 }
 
+/** One of Home's shortcuts at the bottom: an icon over a one-word label, small enough that all fit in a row. */
+@Composable
+private fun HomeShortcut(icon: androidx.compose.ui.graphics.vector.ImageVector, label: String, onClick: () -> Unit, modifier: Modifier = Modifier) {
+    Surface(
+        onClick = onClick,
+        modifier = modifier.heightIn(min = 64.dp),
+        shape = MaterialTheme.shapes.large,
+        color = MaterialTheme.colorScheme.secondaryContainer,
+        contentColor = MaterialTheme.colorScheme.onSecondaryContainer,
+    ) {
+        Column(
+            Modifier.padding(vertical = 10.dp, horizontal = 4.dp),
+            horizontalAlignment = Alignment.CenterHorizontally,
+            verticalArrangement = Arrangement.spacedBy(4.dp),
+        ) {
+            Icon(icon, contentDescription = null, modifier = Modifier.size(22.dp))
+            Text(label, style = MaterialTheme.typography.labelMedium, maxLines = 1)
+        }
+    }
+}
+
 /** Bluetooth audio is chosen, but the phone isn't connected to the car. See [BluetoothAudioCheck]. */
 @Composable
 private fun BluetoothMissingCard() {

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/IntroScreen.kt

@@ -1,877 +0,0 @@
-package app.seb3thehacker.gearslip.ui
-
-import android.content.Context
-import android.content.Intent
-import android.net.Uri
-import android.provider.Settings
-import androidx.activity.compose.BackHandler
-import androidx.compose.animation.core.Animatable
-import androidx.compose.animation.core.CubicBezierEasing
-import androidx.compose.animation.core.FastOutSlowInEasing
-import androidx.compose.animation.core.LinearEasing
-import androidx.compose.animation.core.RepeatMode
-import androidx.compose.animation.core.animateDpAsState
-import androidx.compose.animation.core.animateFloat
-import androidx.compose.animation.core.infiniteRepeatable
-import androidx.compose.animation.core.keyframes
-import androidx.compose.animation.core.rememberInfiniteTransition
-import androidx.compose.animation.core.tween
-import androidx.compose.foundation.Canvas
-import androidx.compose.foundation.BorderStroke
-import androidx.compose.foundation.background
-import androidx.compose.foundation.border
-import androidx.compose.foundation.clickable
-import androidx.compose.foundation.layout.Arrangement
-import androidx.compose.foundation.layout.Box
-import androidx.compose.foundation.layout.BoxWithConstraints
-import androidx.compose.foundation.layout.Column
-import androidx.compose.foundation.layout.Row
-import androidx.compose.foundation.layout.Spacer
-import androidx.compose.foundation.layout.fillMaxSize
-import androidx.compose.foundation.layout.fillMaxWidth
-import androidx.compose.foundation.layout.height
-import androidx.compose.foundation.layout.offset
-import androidx.compose.foundation.layout.padding
-import androidx.compose.foundation.layout.size
-import androidx.compose.foundation.layout.width
-import androidx.compose.foundation.layout.wrapContentWidth
-import androidx.compose.foundation.shape.RoundedCornerShape
-import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.Text
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.LaunchedEffect
-import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableIntStateOf
-import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.remember
-import androidx.compose.runtime.setValue
-import androidx.compose.ui.Alignment
-import androidx.compose.ui.Modifier
-import androidx.compose.ui.draw.clip
-import androidx.compose.ui.geometry.CornerRadius
-import androidx.compose.ui.geometry.Offset
-import androidx.compose.ui.geometry.Size
-import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.graphics.Path
-import androidx.compose.ui.graphics.StrokeCap
-import androidx.compose.ui.graphics.StrokeJoin
-import androidx.compose.ui.graphics.drawscope.DrawScope
-import androidx.compose.ui.graphics.drawscope.Stroke
-import androidx.compose.ui.graphics.drawscope.rotate
-import androidx.compose.ui.graphics.drawscope.scale
-import androidx.compose.ui.graphics.graphicsLayer
-import androidx.compose.ui.platform.LocalContext
-import androidx.compose.ui.platform.LocalDensity
-import androidx.compose.ui.text.TextStyle
-import androidx.compose.ui.text.font.FontWeight
-import androidx.compose.ui.unit.Dp
-import androidx.compose.ui.unit.TextUnit
-import androidx.compose.ui.unit.dp
-import app.seb3thehacker.gearslip.BuildConfig
-import app.seb3thehacker.gearslip.CertProvider
-import app.seb3thehacker.gearslip.AppSettings
-import androidx.compose.runtime.collectAsState
-import androidx.compose.ui.draw.clipToBounds
-import androidx.compose.ui.draw.drawWithContent
-import androidx.compose.ui.graphics.BlendMode
-import androidx.compose.ui.graphics.Brush
-import androidx.compose.ui.graphics.CompositingStrategy
-import androidx.compose.foundation.layout.wrapContentHeight
-import androidx.compose.foundation.layout.PaddingValues
-import androidx.compose.material.icons.Icons
-import androidx.compose.material.icons.filled.PlayArrow
-import androidx.compose.material.icons.filled.Search
-import androidx.compose.runtime.CompositionLocalProvider
-import app.seb3thehacker.gearslip.car.CarSettings
-import app.seb3thehacker.gearslip.car.theme.GsButton
-import app.seb3thehacker.gearslip.car.theme.GsIconButton
-import app.seb3thehacker.gearslip.car.theme.GsThemes
-import app.seb3thehacker.gearslip.car.theme.GsTone
-import app.seb3thehacker.gearslip.car.theme.LocalGsTheme
-import app.seb3thehacker.gearslip.speech.SpeechModels
-import app.seb3thehacker.gearslip.stats.UsageStats
-import kotlin.math.PI
-import kotlin.math.cos
-import kotlin.math.atan2
-import kotlin.math.sqrt
-import kotlin.math.sin
-import kotlin.random.Random
-import kotlinx.coroutines.delay
-
-/**
- * The release intro: a few screens shown once after updating to a new release, before setup. New
- * installs skip it. Its look follows the 0.3 mockup: Material shapes in the phone's own colours,
- * with every size taken from the screen's width so it scales from small phones to tablets.
- */
-object Intro {
-    private const val PREFS = "intro"
-    private const val KEY_SEEN = "seen_release"
-    private const val KEY_STEP = "step"
-
-    /** "0.3" from "0.3.00-alpha": the intro belongs to a release, not to each patch. */
-    val release: String = BuildConfig.VERSION_NAME.split('.').take(2).joinToString(".")
-
-    /**
-     * True once per release for people who used Gearslip before. A new install, or one with its
-     * data cleared, gets the setup guide instead: there's nothing "new" yet, so this release
-     * counts as seen and the next one shows. Install dates can't tell those apart, since
-     * clearing data keeps them, so this goes by what setup left behind; 0.2 saved the same.
-     */
-    fun due(context: Context): Boolean {
-        if (context.getSharedPreferences(PREFS, Context.MODE_PRIVATE).getString(KEY_SEEN, null) == release) return false
-        val usedBefore = AppSettings.hasSeenPermissionsSetup(context) ||
-            AppSettings.hasSkippedCertSetup(context) || CertProvider.hasAnyCert(context)
-        if (!usedBefore) {
-            markSeen(context)
-            return false
-        }
-        return true
-    }
-
-    fun markSeen(context: Context) {
-        context.getSharedPreferences(PREFS, Context.MODE_PRIVATE).edit()
-            .putString(KEY_SEEN, release)
-            .remove(KEY_STEP)
-            .apply()
-    }
-
-    /** A replay from Settings starts at the first page. */
-    fun replay(context: Context) {
-        context.getSharedPreferences(PREFS, Context.MODE_PRIVATE).edit().remove(KEY_STEP).apply()
-    }
-
-    /** The page the intro was on, so an app restart part-way through resumes there. */
-    internal fun savedStep(context: Context): String? =
-        context.getSharedPreferences(PREFS, Context.MODE_PRIVATE).getString(KEY_STEP, null)
-
-    internal fun saveStep(context: Context, step: String) {
-        context.getSharedPreferences(PREFS, Context.MODE_PRIVATE).edit().putString(KEY_STEP, step).apply()
-    }
-}
-
-/** The intro's tones, taken from the phone's own Material You colours like the rest of the app. */
-internal class IntroColors(
-    val surface: Color, val onSurface: Color, val onVariant: Color, val outline: Color,
-    val primary: Color, val onPrimary: Color, val primaryC: Color, val onPrimaryC: Color,
-    val tertiaryC: Color, val onTertiaryC: Color, val secondaryC: Color, val onSecondaryC: Color,
-)
-
-@Composable
-internal fun introColors(): IntroColors {
-    val m = MaterialTheme.colorScheme
-    return IntroColors(
-        surface = m.surface, onSurface = m.onSurface, onVariant = m.onSurfaceVariant, outline = m.outline,
-        primary = m.primary, onPrimary = m.onPrimary, primaryC = m.primaryContainer, onPrimaryC = m.onPrimaryContainer,
-        tertiaryC = m.tertiaryContainer, onTertiaryC = m.onTertiaryContainer,
-        secondaryC = m.secondaryContainer, onSecondaryC = m.onSecondaryContainer,
-    )
-}
-
-/** In the order shown: what's new, what to pick, housekeeping, then the people behind it. */
-private enum class IntroStep { WELCOME, WIRELESS, KNOBS, VOICE, THEME, APPS, GRAPHENE, CHAT, THANKS }
-
-private val Pop = CubicBezierEasing(0.3f, 1.6f, 0.5f, 1f)
-private val Rise = CubicBezierEasing(0.2f, 0.8f, 0.2f, 1f)
-
-@Composable
-fun IntroScreen(onDone: () -> Unit) {
-    val context = LocalContext.current
-    val c = introColors()
-    // The GrapheneOS screen is only news to people running it.
-    val steps = remember {
-        IntroStep.entries.filter { it != IntroStep.GRAPHENE || UsageStats.osName(context) == "GrapheneOS" }
-    }
-    // Turning exploit protection back on restarts the app, so the intro picks up where it was.
-    var index by remember {
-        mutableIntStateOf(steps.indexOfFirst { it.name == Intro.savedStep(context) }.coerceAtLeast(0))
-    }
-    val step = steps[index]
-    LaunchedEffect(step) { Intro.saveStep(context, step.name) }
-    val finish = {
-        Intro.markSeen(context)
-        onDone()
-    }
-    BackHandler(enabled = index > 0) { index-- }
-
-    BoxWithConstraints(Modifier.fillMaxSize().background(c.surface)) {
-        val w = maxWidth
-        val h = maxHeight
-        // The mockup's cqw: one percent of the screen's width.
-        fun cq(n: Float): Dp = w * (n / 100f)
-        val density = LocalDensity.current
-        fun cqSp(n: Float): TextUnit = with(density) { cq(n).toSp() }
-
-        // The step on top, Back and Next under it, the same as the setup guide.
-        Column(Modifier.fillMaxSize()) {
-        Box(Modifier.weight(1f).fillMaxWidth()) {
-        when (step) {
-            IntroStep.WELCOME -> Welcome(c, ::cq, ::cqSp, h)
-            IntroStep.WIRELESS -> BadgeStep(c, ::cq, ::cqSp, c.secondaryC, "Wireless.",
-                "If your car does wireless Android Auto, pair once and leave the cable at home.", step) { WifiIcon(c.onSecondaryC) }
-            IntroStep.KNOBS -> BadgeStep(c, ::cq, ::cqSp, c.tertiaryC, "Knobs work.",
-                "Turn, push, done. No touchscreen? Gearslip doesn't need one anymore.", step) { DialIcon(c.onTertiaryC) }
-            IntroStep.VOICE -> VoiceStep(c, ::cq, ::cqSp, step)
-            IntroStep.GRAPHENE -> BadgeStep(c, ::cq, ::cqSp, c.secondaryC, "Protections back on.",
-                "On GrapheneOS, Gearslip no longer needs exploit protection compatibility mode. If you " +
-                    "turned it on for Gearslip, turn it off to get full protection back.", step,
-                action = "Open app settings" to {
-                    runCatching {
-                        context.startActivity(
-                            Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS, Uri.fromParts("package", context.packageName, null)),
-                        )
-                    }
-                },
-                outlined = true,
-            ) { ShieldIcon(c.onSecondaryC, c.secondaryC) }
-            IntroStep.THANKS -> BadgeStep(c, ::cq, ::cqSp, c.tertiaryC, "Thank you.",
-                "Thanks to your usage notes, Gearslip is confirmed to work in cars newer than 2020. " +
-                    "Each note shows which cars work and which still fail, so I know what to fix next.", step,
-                action = "See which cars work" to { GearslipLinks.open(context, GearslipLinks.CARS) },
-                outlined = true,
-                secondAction = "Support on Liberapay" to { GearslipLinks.open(context, GearslipLinks.LIBERAPAY) },
-            ) { HeartIcon(c.onTertiaryC) }
-            IntroStep.CHAT -> BadgeStep(c, ::cq, ::cqSp, c.primaryC, "Come say hi.",
-                "Gearslip has a chat room on Matrix. Talk with other drivers about cars, apps, and " +
-                    "where Gearslip is headed.", step,
-                action = "Join on Matrix" to { GearslipLinks.open(context, GearslipLinks.MATRIX) },
-                outlined = true,
-            ) { ChatIcon(c.onPrimaryC, c.primaryC) }
-            IntroStep.APPS -> BadgeStep(c, ::cq, ::cqSp, c.secondaryC, "Good company.",
-                "Free, open-source apps that work well in the car. The first in each row works best. Tap one to see it on GitHub.", step,
-                extra = { AppPicks(c, ::cq, ::cqSp, step) }) { StarIcon(c.onSecondaryC) }
-            IntroStep.THEME -> BadgeStep(c, ::cq, ::cqSp, c.tertiaryC, "Your buttons.",
-                "Pick how the car's buttons look. Change it any time in the car's settings.", step,
-                extra = { ThemePicker(c, ::cq, ::cqSp, step) }) { ButtonsIcon(c.onTertiaryC) }
-        }
-        }
-        Column(Modifier.fillMaxWidth().padding(horizontal = cq(8f))) {
-            Dots(c, steps.size, index, ::cq, Modifier.align(Alignment.CenterHorizontally))
-            Spacer(Modifier.height(cq(5f)))
-            PillRow(
-                c, ::cq, ::cqSp,
-                onBack = if (index > 0) ({ index-- }) else null,
-                label = if (index == steps.lastIndex) "Start" else "Next",
-            ) { if (index < steps.lastIndex) index++ else finish() }
-            Spacer(Modifier.height(cq(6f)))
-        }
-        }
-    }
-}
-
-/** 0 to 1 once each time [key] changes, after [delayMs]: drives the entrance of one element. */
-@Composable
-internal fun entrance(key: Any, delayMs: Int, durationMs: Int = 650): Float {
-    val a = remember(key) { Animatable(0f) }
-    LaunchedEffect(key) {
-        delay(delayMs.toLong())
-        a.animateTo(1f, tween(durationMs, easing = LinearEasing))
-    }
-    return a.value
-}
-
-/** Slides up and fades in, like the mockup's `up`. */
-internal fun Modifier.up(p: Float, distance: Dp) = graphicsLayer {
-    val e = Rise.transform(p)
-    alpha = e
-    translationY = (1 - e) * distance.toPx()
-}
-
-/** Grows in with a bounce, like the mockup's `bounce`. */
-internal fun Modifier.pop(p: Float) = graphicsLayer {
-    val e = Pop.transform(p)
-    alpha = p.coerceAtMost(1f)
-    scaleX = 0.5f + 0.5f * e
-    scaleY = 0.5f + 0.5f * e
-}
-
-@Composable
-private fun Welcome(c: IntroColors, cq: (Float) -> Dp, cqSp: (Float) -> TextUnit, height: Dp) {
-    val key = IntroStep.WELCOME
-    val spin by rememberInfiniteTransition(label = "spin").animateFloat(
-        0f, 360f, infiniteRepeatable(tween(18_000, easing = LinearEasing)), label = "spin",
-    )
-    Box(Modifier.fillMaxSize()) {
-        Cookie(c.primaryC, Modifier.size(cq(120f)).offset(x = cq(28f), y = -cq(22f)).align(Alignment.TopEnd).graphicsLayer { rotationZ = spin; alpha = 0.9f })
-        Ticker(c.secondaryC, c.onSecondaryC, "OPEN SOURCE ✦ NO ACCOUNT ✦ YOUR CAR, YOUR PHONE ✦ ", cq, cqSp, reverse = true, tilt = 3f,
-            key = key, modifier = Modifier.align(Alignment.TopCenter).padding(top = height * 0.11f))
-
-        Column(Modifier.align(Alignment.CenterStart).padding(horizontal = cq(8f))) {
-            Text("Welcome to", color = c.onVariant, style = TextStyle(fontSize = cqSp(4.2f), fontWeight = FontWeight.SemiBold),
-                modifier = Modifier.up(entrance(key, 100), cq(7f)))
-            Text(
-                Intro.release, color = c.primary,
-                style = TextStyle(fontSize = cqSp(44f), fontWeight = FontWeight.Black, letterSpacing = cqSp(-2.4f), lineHeight = cqSp(38f)),
-                modifier = Modifier.offset(x = -cq(1.5f)).pop(entrance(key, 250, 900)),
-            )
-            Text(
-                "alpha · the big one", color = c.onTertiaryC,
-                style = TextStyle(fontSize = cqSp(4f), fontWeight = FontWeight.Bold),
-                modifier = Modifier.padding(top = cq(4f)).up(entrance(key, 700), cq(7f))
-                    .clip(RoundedCornerShape(50)).background(c.tertiaryC).padding(horizontal = cq(4.4f), vertical = cq(2.2f)),
-            )
-        }
-
-        Confetti(c, key, Modifier.fillMaxSize())
-    }
-}
-
-/** A tilted band of words scrolling past, slid in from the side when the step opens. */
-@Composable
-private fun Ticker(
-    bg: Color, fg: Color, words: String, cq: (Float) -> Dp, cqSp: (Float) -> TextUnit,
-    reverse: Boolean, tilt: Float, key: Any, modifier: Modifier,
-) {
-    val enter = entrance(key, 400, 800)
-    val scroll by rememberInfiniteTransition(label = "ticker").animateFloat(
-        0f, 1f, infiniteRepeatable(tween(if (reverse) 20_000 else 16_000, easing = LinearEasing)), label = "ticker",
-    )
-    Box(
-        modifier
-            .fillMaxWidth()
-            .graphicsLayer {
-                rotationZ = tilt
-                scaleX = 1.2f
-                val e = Rise.transform(enter)
-                alpha = e
-                translationX = (1 - e) * -cq(30f).toPx()
-            }
-            .background(bg)
-            .padding(vertical = cq(2.6f)),
-    ) {
-        Text(
-            words.repeat(4),
-            color = fg, maxLines = 1, softWrap = false,
-            style = TextStyle(fontSize = cqSp(5f), fontWeight = FontWeight.ExtraBold),
-            modifier = Modifier
-                .wrapContentWidth(Alignment.Start, unbounded = true)
-                .graphicsLayer {
-                    // The text holds the words four times; sliding by half loops cleanly.
-                    val shift = size.width / 2f * (if (reverse) 1 - scroll else scroll)
-                    translationX = -shift
-                },
-        )
-    }
-}
-
-/** Material shapes thrown once from behind the version number. */
-@Composable
-private fun Confetti(c: IntroColors, key: Any, modifier: Modifier) {
-    val p = entrance(key, 450, 1300)
-    val bits = remember {
-        val r = Random(7)
-        List(22) { i ->
-            val a = i / 22f * 2 * PI.toFloat() + r.nextFloat() * 0.4f
-            val d = 30f + r.nextFloat() * 45f
-            Bit(cos(a) * d, sin(a) * d * 1.2f, r.nextInt(-270, 270).toFloat(), i % 4, i % 3)
-        }
-    }
-    if (p <= 0f || p >= 1f) return
-    val tones = listOf(c.primary, c.primaryC, c.tertiaryC, c.secondaryC)
-    Canvas(modifier) {
-        val unit = size.width / 100f
-        val e = CubicBezierEasing(0.15f, 0.7f, 0.3f, 1f).transform(p)
-        val alpha = if (p < 0.7f) 1f else 1f - (p - 0.7f) / 0.3f
-        val origin = Offset(size.width * 0.3f, size.height * 0.42f)
-        bits.forEach { b ->
-            val at = origin + Offset(b.dx * unit * e, b.dy * unit * e)
-            val s = 3.6f * unit * (0.3f + 0.7f * e)
-            rotate(b.spin * e, at) {
-                val color = tones[b.tone].copy(alpha = alpha)
-                when (b.shape) {
-                    0 -> drawCircle(color, s / 2, at)
-                    1 -> drawRoundRect(color, at - Offset(s / 2, s / 2), Size(s, s), androidx.compose.ui.geometry.CornerRadius(unit))
-                    else -> drawRoundRect(color, at - Offset(s / 2, s / 4), Size(s, s / 2), androidx.compose.ui.geometry.CornerRadius(s / 4))
-                }
-            }
-        }
-    }
-}
-
-private class Bit(val dx: Float, val dy: Float, val spin: Float, val tone: Int, val shape: Int)
-
-/** One idea per screen: a spinning cookie with an icon, a headline, a line of text, maybe a button. */
-@Composable
-private fun BadgeStep(
-    c: IntroColors, cq: (Float) -> Dp, cqSp: (Float) -> TextUnit, badge: Color,
-    title: String, body: String, key: Any,
-    action: Pair<String, () -> Unit>? = null, outlined: Boolean = false,
-    secondAction: Pair<String, () -> Unit>? = null,
-    extra: (@Composable () -> Unit)? = null,
-    icon: @Composable () -> Unit,
-) {
-    val spin by rememberInfiniteTransition(label = "spin").animateFloat(
-        0f, 360f, infiniteRepeatable(tween(18_000, easing = LinearEasing)), label = "spin",
-    )
-    Column(
-        Modifier.fillMaxSize().padding(horizontal = cq(8f)),
-        verticalArrangement = Arrangement.Center,
-    ) {
-        Box(Modifier.size(cq(34f)).pop(entrance(key, 50, 800)), contentAlignment = Alignment.Center) {
-            Cookie(badge, Modifier.fillMaxSize().graphicsLayer { rotationZ = spin })
-            Box(Modifier.size(cq(15f))) { icon() }
-        }
-        Spacer(Modifier.height(cq(8f)))
-        Text(
-            title, color = c.onSurface,
-            style = TextStyle(fontSize = cqSp(13.5f), fontWeight = FontWeight.Black, letterSpacing = cqSp(-0.6f), lineHeight = cqSp(12.5f)),
-            modifier = Modifier.up(entrance(key, 200, 700), cq(7f)),
-        )
-        Spacer(Modifier.height(cq(4f)))
-        Text(
-            body, color = c.onVariant,
-            style = TextStyle(fontSize = cqSp(4.5f), lineHeight = cqSp(6.5f)),
-            modifier = Modifier.up(entrance(key, 350, 700), cq(7f)),
-        )
-        extra?.invoke()
-        listOfNotNull(action, secondAction).forEachIndexed { i, (label, onClick) ->
-            Spacer(Modifier.height(if (i > 0) cq(3f) else if (outlined) cq(7f) else cq(9f)))
-            Text(
-                label,
-                color = if (outlined) c.primary else c.onPrimary,
-                style = TextStyle(fontSize = cqSp(if (outlined) 4.4f else 4.6f), fontWeight = FontWeight.Bold),
-                modifier = Modifier
-                    .up(entrance(key, 500 + i * 150, 700), cq(7f))
-                    .clip(RoundedCornerShape(50))
-                    .then(
-                        if (outlined) Modifier.border(BorderStroke(2.dp, c.outline), RoundedCornerShape(50))
-                        else Modifier.background(c.primary),
-                    )
-                    .clickable(onClick = onClick)
-                    .padding(horizontal = if (outlined) cq(7f) else cq(9f), vertical = if (outlined) cq(3.6f) else cq(4.2f)),
-            )
-        }
-    }
-}
-
-/**
- * Voice: a few things to say, drifting past, and a button that fetches both speech models so the
- * assistant works the first time someone tries it in the car.
- */
-@Composable
-private fun VoiceStep(c: IntroColors, cq: (Float) -> Dp, cqSp: (Float) -> TextUnit, key: IntroStep) {
-    val context = LocalContext.current
-    remember { SpeechModels.init(context) }
-    val needed = SpeechModels.RECOMMENDED
-    val states = needed.map { SpeechModels.state(it).collectAsState().value }
-    val ready = states.all { it == SpeechModels.State.Ready }
-    val label = when {
-        states.any { it is SpeechModels.State.Downloading } ->
-            "Downloading, ${needed.zip(states).sumOf { (m, st) -> m.downloadMb * percentOf(st) } / needed.sumOf { it.downloadMb }}%"
-        states.any { it is SpeechModels.State.Failed } -> "Download failed. Try again"
-        else -> "Download voice, ${needed.sumOf { it.downloadMb }} MB"
-    }
-    BadgeStep(
-        c, cq, cqSp, c.primaryC, "Just say it.",
-        "Tap the mic, or press the talk button on your wheel, and speak. Your phone turns speech " +
-            "into text by itself, and nothing you say leaves it. Say \"help\" in the car for the full list.",
-        key,
-        action = if (ready) null else label to { SpeechModels.downloadRecommended(context) },
-        outlined = true,
-        extra = { CommandDrift(c, cq, cqSp, key) },
-    ) { MicIcon(c.onPrimaryC) }
-}
-
-private fun percentOf(state: SpeechModels.State) = when (state) {
-    SpeechModels.State.Ready -> 100
-    is SpeechModels.State.Downloading -> state.percent
-    else -> 0
-}
-
-private val SAMPLE_COMMANDS = listOf(
-    "Play Daft Punk", "What's playing?", "Next song",
-    "Call Mom", "Open Organic Maps", "Pause", "Help",
-)
-
-/** Example commands rising slowly through a window that fades at both edges. */
-@Composable
-private fun CommandDrift(c: IntroColors, cq: (Float) -> Dp, cqSp: (Float) -> TextUnit, key: Any) {
-    val scroll by rememberInfiniteTransition(label = "drift").animateFloat(
-        0f, 1f, infiniteRepeatable(tween(SAMPLE_COMMANDS.size * 2_200, easing = LinearEasing)), label = "drift",
-    )
-    Box(
-        Modifier
-            .padding(top = cq(6f))
-            .fillMaxWidth()
-            .height(cq(34f))
-            .up(entrance(key, 500, 700), cq(7f))
-            .graphicsLayer { compositingStrategy = CompositingStrategy.Offscreen }
-            .drawWithContent {
-                drawContent()
-                drawRect(
-                    Brush.verticalGradient(0f to Color.Transparent, 0.25f to Color.Black, 0.75f to Color.Black, 1f to Color.Transparent),
-                    blendMode = BlendMode.DstIn,
-                )
-            }
-            .clipToBounds(),
-    ) {
-        Column(
-            Modifier
-                .wrapContentHeight(Alignment.Top, unbounded = true)
-                // The list is there twice; rising by half loops cleanly.
-                .graphicsLayer { translationY = -size.height / 2f * scroll },
-            verticalArrangement = Arrangement.spacedBy(cq(2.4f)),
-        ) {
-            repeat(2) {
-                SAMPLE_COMMANDS.forEach { say ->
-                    Text(
-                        "\u201c$say\u201d", color = c.onSecondaryC,
-                        style = TextStyle(fontSize = cqSp(4.4f), fontWeight = FontWeight.SemiBold),
-                        modifier = Modifier
-                            .clip(RoundedCornerShape(50))
-                            .background(c.secondaryC)
-                            .padding(horizontal = cq(4.4f), vertical = cq(2f)),
-                    )
-                }
-            }
-        }
-    }
-}
-
-/** Each kind of app with its picks, the first recommended most. */
-private val APP_PICKS = listOf(
-    "Maps" to listOf(
-        "Organic Maps" to "https://github.com/organicmaps/organicmaps",
-        "Vela" to "https://github.com/PimpinPumpkin/Vela",
-    ),
-    "Music" to listOf(
-        "ViVi Music" to "https://github.com/vivizzz007/vivi-music",
-        "Metrolist" to "https://github.com/MetrolistGroup/Metrolist",
-    ),
-    "Podcasts" to listOf(
-        "AntennaPod" to "https://github.com/AntennaPod/AntennaPod",
-    ),
-)
-
-/** One row per kind, with a chip per app opening its GitHub page; the rows arrive one after another. */
-@Composable
-private fun AppPicks(c: IntroColors, cq: (Float) -> Dp, cqSp: (Float) -> TextUnit, key: IntroStep) {
-    val context = LocalContext.current
-    Column(Modifier.padding(top = cq(6f)), verticalArrangement = Arrangement.spacedBy(cq(2.6f))) {
-        APP_PICKS.forEachIndexed { i, (kind, apps) ->
-            Column(
-                Modifier
-                    .fillMaxWidth()
-                    .up(entrance(key, 500 + i * 120, 700), cq(7f))
-                    .clip(RoundedCornerShape(cq(5f)))
-                    .background(c.secondaryC)
-                    .padding(horizontal = cq(4f), vertical = cq(3f)),
-            ) {
-                Text(kind.uppercase(), color = c.onSecondaryC.copy(alpha = 0.7f),
-                    style = TextStyle(fontSize = cqSp(3.2f), fontWeight = FontWeight.Bold, letterSpacing = cqSp(0.3f)),
-                    modifier = Modifier.padding(start = cq(1f), bottom = cq(1.6f)))
-                Row(horizontalArrangement = Arrangement.spacedBy(cq(2f))) {
-                    apps.forEach { (name, url) ->
-                        Text(
-                            "$name ↗", color = c.onSecondaryC,
-                            style = TextStyle(fontSize = cqSp(4.4f), fontWeight = FontWeight.ExtraBold),
-                            maxLines = 1,
-                            modifier = Modifier
-                                .clip(RoundedCornerShape(50))
-                                .border(BorderStroke(1.5.dp, c.onSecondaryC.copy(alpha = 0.35f)), RoundedCornerShape(50))
-                                .clickable {
-                                    runCatching {
-                                        context.startActivity(Intent(Intent.ACTION_VIEW, Uri.parse(url)).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK))
-                                    }
-                                }
-                                .padding(horizontal = cq(3.6f), vertical = cq(2f)),
-                        )
-                    }
-                }
-            }
-        }
-    }
-}
-
-/**
- * The car's button styles side by side, each drawn in its own style, and a row of real car
- * controls below that redraws in whichever is picked. Picking saves it, so the car shows it too.
- */
-@Composable
-private fun ThemePicker(c: IntroColors, cq: (Float) -> Dp, cqSp: (Float) -> TextUnit, key: IntroStep) {
-    val chosenId by CarSettings.uiTheme.collectAsState()
-    val chosen = GsThemes.byId(chosenId)
-    // Flat first: it's the default.
-    val themes = listOf(GsThemes.Flat) + GsThemes.builtIn.filter { it != GsThemes.Flat }
-    Column(
-        Modifier.padding(top = cq(7f)).fillMaxWidth().up(entrance(key, 500, 700), cq(7f)),
-        verticalArrangement = Arrangement.spacedBy(cq(6f)),
-    ) {
-        Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(cq(3f))) {
-            themes.forEach { theme ->
-                CompositionLocalProvider(LocalGsTheme provides theme) {
-                    GsButton(
-                        onClick = { CarSettings.setUiTheme(theme.id) },
-                        modifier = Modifier.weight(1f),
-                        tone = if (theme == chosen) GsTone.Primary else GsTone.Neutral,
-                        contentPadding = PaddingValues(horizontal = cq(1f), vertical = cq(3f)),
-                    ) {
-                        Text(
-                            if (theme == chosen) "✓ ${theme.name}" else theme.name,
-                            style = TextStyle(fontSize = cqSp(4.2f), fontWeight = FontWeight.Bold),
-                            maxLines = 1,
-                        )
-                    }
-                }
-            }
-        }
-        // What the car shows: the player's controls and a full-width action.
-        CompositionLocalProvider(LocalGsTheme provides chosen) {
-            Row(
-                Modifier.fillMaxWidth(),
-                horizontalArrangement = Arrangement.spacedBy(cq(3f)),
-                verticalAlignment = Alignment.CenterVertically,
-            ) {
-                GsIconButton(Icons.Filled.Search, "Search", onClick = {}, size = cq(15f), iconSize = cq(7f))
-                GsIconButton(Icons.Filled.PlayArrow, "Play", onClick = {}, tone = GsTone.Primary, size = cq(15f), iconSize = cq(8f))
-                GsButton(
-                    onClick = {},
-                    modifier = Modifier.weight(1f).height(cq(15f)),
-                    tone = GsTone.Tonal,
-                ) { Text("Navigate", style = TextStyle(fontSize = cqSp(4.6f), fontWeight = FontWeight.Bold)) }
-            }
-        }
-    }
-}
-
-/** Three keys of a keypad, pressing one after another. */
-@Composable
-private fun ButtonsIcon(color: Color) {
-    val t by rememberInfiniteTransition(label = "keys").animateFloat(
-        0f, 3f, infiniteRepeatable(tween(2400, easing = LinearEasing)), label = "keys",
-    )
-    Canvas(Modifier.fillMaxSize()) {
-        inIconBox {
-            listOf(6f, 19f, 32f).forEachIndexed { i, x ->
-                // Each key dips for a moment while its turn comes round.
-                val dip = (1f - kotlin.math.abs(t - i - 0.5f) * 2f).coerceIn(0f, 1f) * 4f
-                drawRoundRect(color.copy(alpha = 0.45f), Offset(x, 16f + 4f), Size(10f, 16f),
-                    androidx.compose.ui.geometry.CornerRadius(3f))
-                drawRoundRect(color, Offset(x, 16f + dip), Size(10f, 16f), androidx.compose.ui.geometry.CornerRadius(3f))
-            }
-        }
-    }
-}
-
-/** Material's scalloped "cookie": a circle whose radius waves around its edge. */
-@Composable
-internal fun Cookie(color: Color, modifier: Modifier) {
-    Canvas(modifier) {
-        val unit = size.minDimension / 100f
-        val path = Path()
-        var deg = 0
-        while (deg <= 360) {
-            val a = deg * PI / 180
-            val r = (44 + 4.5 * cos(9 * a)) * unit
-            val x = center.x + (r * cos(a)).toFloat()
-            val y = center.y + (r * sin(a)).toFloat()
-            if (deg == 0) path.moveTo(x, y) else path.lineTo(x, y)
-            deg += 3
-        }
-        path.close()
-        drawPath(path, color)
-    }
-}
-
-/** Draws in the mockup's 48-unit icon box. */
-private inline fun DrawScope.inIconBox(block: DrawScope.() -> Unit) {
-    val s = size.minDimension / 48f
-    scale(s, s, Offset.Zero) { block() }
-}
-
-@Composable
-internal fun WifiIcon(color: Color) {
-    val t = rememberInfiniteTransition(label = "wifi")
-    val waves = (0..2).map { i ->
-        t.animateFloat(
-            0.35f, 1f,
-            infiniteRepeatable(tween(800, delayMillis = 0, easing = FastOutSlowInEasing), RepeatMode.Reverse,
-                initialStartOffset = androidx.compose.animation.core.StartOffset(i * 200)),
-            label = "wave$i",
-        )
-    }
-    Canvas(Modifier.fillMaxSize()) {
-        inIconBox {
-            val stroke = Stroke(5f, cap = StrokeCap.Round)
-            // The mockup's three arcs, inner to outer: radius r through (24 ± half, y).
-            listOf(Triple(8f, 6f, 34f), Triple(18f, 13f, 26f), Triple(28f, 20f, 18f)).forEachIndexed { i, (r, half, y) ->
-                val cy = y + sqrt(r * r - half * half)
-                val start = Math.toDegrees(atan2((y - cy).toDouble(), (-half).toDouble())).toFloat()
-                val end = Math.toDegrees(atan2((y - cy).toDouble(), half.toDouble())).toFloat()
-                drawArc(color.copy(alpha = waves[i].value), start, (end - start + 360f) % 360f, false,
-                    Offset(24f - r, cy - r), Size(2 * r, 2 * r), style = stroke)
-            }
-            drawCircle(color, 3.6f, Offset(24f, 41f))
-        }
-    }
-}
-
-@Composable
-private fun DialIcon(color: Color) {
-    val angle by rememberInfiniteTransition(label = "dial").animateFloat(
-        -70f, -70f,
-        infiniteRepeatable(keyframes {
-            durationMillis = 2600
-            -70f at 0 using CubicBezierEasing(0.5f, 0f, 0.3f, 1f)
-            70f at 1040
-            70f at 1430 using CubicBezierEasing(0.5f, 0f, 0.3f, 1f)
-            -70f at 2470
-        }),
-        label = "dial",
-    )
-    Canvas(Modifier.fillMaxSize()) {
-        inIconBox {
-            drawCircle(color, 19f, Offset(24f, 24f), style = Stroke(5f))
-            rotate(angle, Offset(24f, 24f)) {
-                drawRoundRect(color, Offset(21.5f, 7f), Size(5f, 13f), androidx.compose.ui.geometry.CornerRadius(2.5f))
-            }
-        }
-    }
-}
-
-@Composable
-internal fun MicIcon(color: Color) {
-    val t = rememberInfiniteTransition(label = "mic")
-    val waves = (0..1).map { i ->
-        t.animateFloat(
-            0.25f, 1f,
-            infiniteRepeatable(tween(700, easing = FastOutSlowInEasing), RepeatMode.Reverse,
-                initialStartOffset = androidx.compose.animation.core.StartOffset(i * 250)),
-            label = "mic$i",
-        )
-    }
-    Canvas(Modifier.fillMaxSize()) {
-        inIconBox {
-            drawRoundRect(color, Offset(18f, 5f), Size(12f, 22f), androidx.compose.ui.geometry.CornerRadius(6f))
-            val stroke = Stroke(4f, cap = StrokeCap.Round)
-            drawArc(color, 0f, 180f, false, Offset(12f, 14f), Size(24f, 22f), style = stroke)
-            drawLine(color, Offset(24f, 36f), Offset(24f, 42f), 4f, StrokeCap.Round)
-            // Sound waves either side, pulsing as if someone's talking.
-            listOf(1f to 0, -1f to 0, 1f to 1, -1f to 1).forEach { (side, i) ->
-                val r = if (i == 0) 15f else 21f
-                drawArc(color.copy(alpha = waves[i].value), if (side > 0) -35f else 145f, 70f, false,
-                    Offset(24f - r, 16f - r), Size(2 * r, 2 * r), style = stroke)
-            }
-        }
-    }
-}
-
-@Composable
-internal fun StarIcon(color: Color) {
-    val turn by rememberInfiniteTransition(label = "star").animateFloat(
-        -8f, 8f, infiniteRepeatable(tween(1600, easing = FastOutSlowInEasing), RepeatMode.Reverse), label = "star",
-    )
-    Canvas(Modifier.fillMaxSize()) {
-        inIconBox {
-            val star = Path()
-            for (i in 0 until 10) {
-                val r = if (i % 2 == 0) 20f else 8.5f
-                val a = (-90 + i * 36) * PI / 180
-                val x = 24f + (r * cos(a)).toFloat()
-                val y = 25f + (r * sin(a)).toFloat()
-                if (i == 0) star.moveTo(x, y) else star.lineTo(x, y)
-            }
-            star.close()
-            rotate(turn, Offset(24f, 25f)) { drawPath(star, color) }
-        }
-    }
-}
-
-@Composable
-internal fun ShieldIcon(color: Color, tick: Color) {
-    val p = entrance(IntroStep.GRAPHENE, 800, 500)
-    Canvas(Modifier.fillMaxSize()) {
-        inIconBox {
-            val shield = Path().apply {
-                moveTo(24f, 4f); lineTo(40f, 10f); lineTo(40f, 22f)
-                cubicTo(40f, 32f, 33f, 40f, 24f, 44f)
-                cubicTo(15f, 40f, 8f, 32f, 8f, 22f)
-                lineTo(8f, 10f); close()
-            }
-            drawPath(shield, color)
-            drawPartialStroke(listOf(Offset(16f, 24f), Offset(22f, 30f), Offset(33f, 18f)), p, tick, 4.5f)
-        }
-    }
-}
-
-/** A speech bubble with three dots that pulse, like someone typing. */
-@Composable
-private fun ChatIcon(color: Color, dots: Color) {
-    val t = rememberInfiniteTransition(label = "typing")
-    val pulse = (0..2).map { i ->
-        t.animateFloat(
-            0.35f, 1f,
-            infiniteRepeatable(tween(500, easing = FastOutSlowInEasing), RepeatMode.Reverse,
-                initialStartOffset = androidx.compose.animation.core.StartOffset(i * 170)),
-            label = "dot$i",
-        )
-    }
-    Canvas(Modifier.fillMaxSize()) {
-        inIconBox {
-            drawRoundRect(color, Offset(4f, 7f), Size(40f, 28f), CornerRadius(10f, 10f))
-            drawPath(Path().apply { moveTo(12f, 33f); lineTo(10f, 43f); lineTo(22f, 33f); close() }, color)
-            pulse.forEachIndexed { i, a -> drawCircle(dots.copy(alpha = a.value), 3.2f, Offset(15f + i * 9f, 21f)) }
-        }
-    }
-}
-
-@Composable
-internal fun HeartIcon(color: Color) {
-    val beat by rememberInfiniteTransition(label = "beat").animateFloat(
-        1f, 1f,
-        infiniteRepeatable(keyframes {
-            durationMillis = 1400
-            1f at 0; 1.16f at 210; 1f at 420; 1.1f at 630; 1f at 840
-        }),
-        label = "beat",
-    )
-    Canvas(Modifier.fillMaxSize()) {
-        inIconBox {
-            scale(beat, beat, Offset(24f, 24f)) {
-                val heart = Path().apply {
-                    moveTo(24f, 41f)
-                    cubicTo(10f, 31f, 5f, 23f, 5f, 16f)
-                    cubicTo(5f, 10f, 10f, 6f, 15f, 6f)
-                    cubicTo(19f, 6f, 22f, 8f, 24f, 12f)
-                    cubicTo(26f, 8f, 29f, 6f, 33f, 6f)
-                    cubicTo(38f, 6f, 43f, 10f, 43f, 16f)
-                    cubicTo(43f, 23f, 38f, 31f, 24f, 41f)
-                    close()
-                }
-                drawPath(heart, color)
-            }
-        }
-    }
-}
-
-/** A polyline drawn up to [progress] of its length, so a tick can sweep in. */
-private fun DrawScope.drawPartialStroke(points: List<Offset>, progress: Float, color: Color, width: Float) {
-    if (progress <= 0f) return
-    val lengths = points.zipWithNext { a, b -> (b - a).getDistance() }
-    var left = lengths.sum() * FastOutSlowInEasing.transform(progress.coerceAtMost(1f))
-    val path = Path().apply { moveTo(points[0].x, points[0].y) }
-    for (i in lengths.indices) {
-        if (left <= 0f) break
-        val f = (left / lengths[i]).coerceAtMost(1f)
-        val to = points[i] + (points[i + 1] - points[i]) * f
-        path.lineTo(to.x, to.y)
-        left -= lengths[i]
-    }
-    drawPath(path, color, style = Stroke(width, cap = StrokeCap.Round, join = StrokeJoin.Round))
-}
-
-@Composable
-internal fun Dots(c: IntroColors, count: Int, current: Int, cq: (Float) -> Dp, modifier: Modifier) {
-    Row(modifier, horizontalArrangement = Arrangement.spacedBy(cq(2f))) {
-        repeat(count) { i ->
-            val on = i == current
-            val width by animateDpAsState(if (on) cq(7f) else cq(2f), tween(300), label = "dot")
-            Box(
-                Modifier
-                    .size(width, cq(2f))
-                    .clip(RoundedCornerShape(50))
-                    .background(if (on) c.primary else c.outline.copy(alpha = 0.45f)),
-            )
-        }
-    }
-}
-

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/LogsScreen.kt

@@ -8,6 +8,7 @@ import androidx.compose.foundation.layout.navigationBarsPadding
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.fillMaxSize
@@ -55,6 +56,9 @@ fun LogsScreen(onBack: () -> Unit) {
     val version by GearslipLog.version.collectAsStateWithLifecycle()
     val lines = remember(version) { GearslipLog.snapshot() }
 
+    var pastOpen by remember { mutableStateOf(false) }
+    if (pastOpen) PastLogsDialog(onDismiss = { pastOpen = false })
+
     val listState = rememberLazyListState()
     val atEnd by remember {
         derivedStateOf {
@@ -96,17 +100,16 @@ fun LogsScreen(onBack: () -> Unit) {
                     Button(
                         onClick = {
                             scope.launch {
-                            val uri = withContext(Dispatchers.IO) { GearslipLog.shareableFile(context) }
-                            val send = Intent(Intent.ACTION_SEND)
-                                .setType("text/plain")
-                                .putExtra(Intent.EXTRA_SUBJECT, "Gearslip log")
-                                .putExtra(Intent.EXTRA_STREAM, uri)
-                                .addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
-                            context.startActivity(Intent.createChooser(send, "Share log"))
-                        }
+                                val uri = withContext(Dispatchers.IO) { GearslipLog.shareableFile(context) }
+                                shareLog(context, uri)
+                            }
                         },
                         modifier = Modifier.weight(1f).height(56.dp),
                     ) { Text("Share") }
+                    OutlinedButton(
+                        onClick = { pastOpen = true },
+                        modifier = Modifier.weight(1f).height(56.dp),
+                    ) { Text("Earlier") }
                     OutlinedButton(
                         onClick = { GearslipLog.clearLive() },
                         modifier = Modifier.weight(1f).height(56.dp),
@@ -153,6 +156,68 @@ fun LogsScreen(onBack: () -> Unit) {
     }
 }
 
+private fun shareLog(context: android.content.Context, uri: android.net.Uri) {
+    val send = Intent(Intent.ACTION_SEND)
+        .setType("text/plain")
+        .putExtra(Intent.EXTRA_SUBJECT, "Gearslip log")
+        .putExtra(Intent.EXTRA_STREAM, uri)
+        .addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
+    context.startActivity(Intent.createChooser(send, "Share log"))
+}
+
+/**
+ * Logs from earlier launches. Opening the app after a crash starts a new log, so the one that
+ * saw the crash is only reachable here.
+ */
+@Composable
+private fun PastLogsDialog(onDismiss: () -> Unit) {
+    val context = LocalContext.current
+    val scope = rememberCoroutineScope()
+    val logs by androidx.compose.runtime.produceState<List<GearslipLog.PastLog>?>(null) {
+        value = withContext(Dispatchers.IO) { GearslipLog.pastLogs(context) }
+    }
+    val format = remember { java.text.SimpleDateFormat("EEE d MMM, h:mm a", java.util.Locale.getDefault()) }
+    androidx.compose.material3.AlertDialog(
+        onDismissRequest = onDismiss,
+        title = { Text("Earlier logs") },
+        text = {
+            val list = logs
+            when {
+                list == null -> Text("Loading…")
+                list.isEmpty() -> Text("No earlier logs yet. Each time Gearslip starts, it begins a new one.")
+                else -> LazyColumn {
+                    itemsIndexed(list) { _, log ->
+                        androidx.compose.foundation.layout.Column(
+                            Modifier
+                                .fillMaxWidth()
+                                .clickable {
+                                    scope.launch {
+                                        val uri = withContext(Dispatchers.IO) { GearslipLog.shareableFile(context, log.file) }
+                                        shareLog(context, uri)
+                                    }
+                                }
+                                .padding(vertical = 12.dp),
+                        ) {
+                            Text(log.started?.let(format::format) ?: log.file.name, style = MaterialTheme.typography.titleMedium)
+                            val detail = listOfNotNull(
+                                "Crashed".takeIf { log.crashed },
+                                log.car,
+                                "${(log.file.length() + 1023) / 1024} KB",
+                            ).joinToString(" · ")
+                            Text(
+                                detail,
+                                style = MaterialTheme.typography.bodyMedium,
+                                color = if (log.crashed) MaterialTheme.colorScheme.error else MaterialTheme.colorScheme.onSurfaceVariant,
+                            )
+                        }
+                    }
+                }
+            }
+        },
+        confirmButton = { androidx.compose.material3.TextButton(onClick = onDismiss) { Text("Close") } },
+    )
+}
+
 /** Lines look like "HH:mm:ss.SSS L message"; the level letter sits at index 13. */
 @Composable
 private fun colorFor(line: String): Color = when (line.getOrNull(13)) {

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/RecommendedApps.kt

@@ -57,6 +57,9 @@ private val recommended = listOf(
     "Podcasts" to listOf(
         RecommendedApp("AntennaPod", "de.danoeh.antennapod", "https://github.com/AntennaPod/AntennaPod", "Podcasts, chapters and all."),
     ),
+    "Other cool apps" to listOf(
+        RecommendedApp("RF Sentinel", "com.rfsentinel.app", "https://github.com/CIS-C0/RFSentinel", "Spots trackers and cameras nearby."),
+    ),
 )
 
 /** Opened from Settings: the same list the setup guide ends with. */
@@ -135,11 +138,13 @@ private fun AppRow(app: RecommendedApp, onOpen: () -> Unit) {
             if (icon != null) {
                 Image(icon.toBitmap(96, 96).asImageBitmap(), contentDescription = null, Modifier.fillMaxSize())
             } else {
-                Text(app.name.take(1), style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.Bold)
+                Text(app.name.take(1), style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.Bold, color = MaterialTheme.colorScheme.onSurface)
             }
         }
         Column(Modifier.weight(1f).padding(horizontal = 14.dp)) {
-            Text(app.name, style = MaterialTheme.typography.titleMedium)
+            // Colours set outright: the setup guide draws this on its own background, with no
+            // Surface to hand down a content colour, and unset text came out dark on dark.
+            Text(app.name, style = MaterialTheme.typography.titleMedium, color = MaterialTheme.colorScheme.onSurface)
             Text(app.about, style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.onSurfaceVariant)
             if (icon != null) {
                 Row(verticalAlignment = Alignment.CenterVertically, modifier = Modifier.padding(top = 4.dp)) {

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/SettingsScreen.kt

@@ -79,12 +79,7 @@ import kotlinx.coroutines.withContext
 fun SettingsScreen(
     onBack: () -> Unit,
     onOpenRecommendedApps: () -> Unit,
-    onOpenWhatsNew: () -> Unit,
-    onOpenHelp: () -> Unit,
-    onOpenCarPreview: () -> Unit,
-    onOpenLogs: () -> Unit,
     onReplayTutorial: () -> Unit,
-    onReplayIntro: () -> Unit,
     atUsageNotes: Boolean = false,
 ) {
     val scroll = rememberScrollState()
@@ -119,13 +114,23 @@ fun SettingsScreen(
             verticalArrangement = Arrangement.spacedBy(24.dp),
         ) {
             Spacer(Modifier.height(0.dp))
+            SettingsSection {
+                val context = LocalContext.current
+                SettingsRow(
+                    "What's new",
+                    Modifier.clickable { GearslipLinks.open(context, GearslipLinks.RELEASE_NOTES) },
+                    subtitle = "Read the ${BuildConfig.VERSION_NAME} release notes on GitHub",
+                    icon = Icons.Filled.Star,
+                    trailing = { Arrow() },
+                )
+            }
             SettingsSection(
                 "Support Gearslip",
                 footer = "Gearslip is free, with no ads and no tracking. Your support keeps it going.",
             ) { DonateRows() }
             ConnectionSection()
-            HelpSection(onOpenHelp, onOpenCarPreview, onOpenLogs)
             CarAudioSection()
+            CarScreenSection()
             VoiceModelSection()
             if (SHOW_RECOMMENDED_APPS) AppsSection(onOpenRecommendedApps)
             SettingsSection(
@@ -135,7 +140,8 @@ fun SettingsScreen(
             ) { UsageStatsRows() }
             SettingsSection("Updates") { UpdateRow() }
             CertificateSection()
-            AboutSection(onOpenWhatsNew, onReplayTutorial, onReplayIntro)
+            AboutSection(onReplayTutorial)
+            if (BuildConfig.DEBUG) DebugSection()
             Spacer(Modifier.height(16.dp))
         }
     }
@@ -148,26 +154,10 @@ private fun Arrow() = Icon(
     tint = MaterialTheme.colorScheme.onSurfaceVariant,
 )
 
-/** What's new, the replays, and where Gearslip lives outside the app. */
+/** The setup guide replay, and where Gearslip lives outside the app. */
 @Composable
-private fun AboutSection(onOpenWhatsNew: () -> Unit, onReplayTutorial: () -> Unit, onReplayIntro: () -> Unit) {
+private fun AboutSection(onReplayTutorial: () -> Unit) {
     SettingsSection("About") {
-        SettingsRow(
-            "What's new",
-            Modifier.clickable(onClick = onOpenWhatsNew),
-            subtitle = "Version ${BuildConfig.VERSION_NAME}",
-            icon = Icons.Filled.Star,
-            trailing = { Arrow() },
-        )
-        SettingsDivider()
-        SettingsRow(
-            "Replay the ${Intro.release} intro",
-            Modifier.clickable(onClick = onReplayIntro),
-            subtitle = "What's in this release, in a few taps",
-            icon = Icons.Filled.Star,
-            trailing = { Arrow() },
-        )
-        SettingsDivider()
         SettingsRow(
             "Replay the setup guide",
             Modifier.clickable(onClick = onReplayTutorial),
@@ -199,48 +189,25 @@ private fun ConnectionSection() {
     }
 }
 
-/** Connection help, and the tools for checking what Gearslip does. */
+/** Tools for testing a debug build; release builds never show this section. */
 @Composable
-private fun HelpSection(onOpenHelp: () -> Unit, onOpenCarPreview: () -> Unit, onOpenLogs: () -> Unit) {
+private fun DebugSection() {
     val context = LocalContext.current
-    val status by SessionStatus.state.collectAsState()
-    val live = status.phase == SessionStatus.Phase.CONNECTING || status.phase == SessionStatus.Phase.PROJECTING
-    SettingsSection("Help and tools") {
+    SettingsSection("Debug build") {
         SettingsRow(
-            "Connection help",
-            Modifier.clickable(onClick = onOpenHelp),
-            subtitle = "Which cars work, and what to set up first",
-            icon = Icons.Filled.Info,
-            trailing = { Arrow() },
+            "Send a test message",
+            Modifier.clickable { TestMessage.post(context) },
+            subtitle = "Posts a message notification to read on the car",
+            icon = Icons.AutoMirrored.Filled.Send,
         )
-        // The preview draws the car screen on the phone, so it waits until no car is using it.
-        if (!live) {
-            SettingsDivider()
-            SettingsRow(
-                "Car preview",
-                Modifier.clickable(onClick = onOpenCarPreview),
-                subtitle = "See the car screen on your phone",
-                icon = Icons.Filled.PlayArrow,
-                trailing = { Arrow() },
-            )
-        }
         SettingsDivider()
+        val badge by CarSettings.debugBadge.collectAsState()
         SettingsRow(
-            "Live logs",
-            Modifier.clickable(onClick = onOpenLogs),
-            subtitle = "What Gearslip and the car are saying to each other",
-            icon = Icons.AutoMirrored.Filled.List,
-            trailing = { Arrow() },
+            "Debug badge on the car screen",
+            Modifier.clickable { CarSettings.setDebugBadge(!badge) },
+            subtitle = "Turn it off for screenshots",
+            trailing = { Switch(checked = badge, onCheckedChange = null) },
         )
-        if (BuildConfig.DEBUG) {
-            SettingsDivider()
-            SettingsRow(
-                "Send a test message",
-                Modifier.clickable { TestMessage.post(context) },
-                subtitle = "Debug builds only. Posts a message notification to read on the car",
-                icon = Icons.AutoMirrored.Filled.Send,
-            )
-        }
     }
 }
 
@@ -262,7 +229,7 @@ private fun CarAudioSection() {
         SettingsRow(
             "USB",
             Modifier.selectable(usb, role = Role.RadioButton) { CarSettings.setPipeAudio(true) },
-            subtitle = "Clearer sound with no delay. Android asks to share audio once each drive",
+            subtitle = "Clearer sound with no delay. Each drive, Android asks you to share your screen, which lets Gearslip send the sound",
             trailing = { RadioButton(selected = usb, onClick = null) },
         )
     }

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/SetupGuideScreen.kt

@@ -93,6 +93,9 @@ import app.seb3thehacker.gearslip.host.AndroidAuto
 import app.seb3thehacker.gearslip.notify.GearslipNotificationListener
 import app.seb3thehacker.gearslip.stats.UsageStats
 import androidx.compose.runtime.DisposableEffect
+import androidx.compose.animation.core.RepeatMode
+import androidx.compose.animation.core.FastOutSlowInEasing
+import androidx.compose.foundation.layout.offset
 
 /**
  * One page of the guide. [permissions] drives a system permission dialog; [command] is an adb
@@ -100,6 +103,9 @@ import androidx.compose.runtime.DisposableEffect
  * settings screen) without by itself finishing the page. Everything is skippable: none of this
  * can be verified as done, only offered.
  */
+/** The guide's colours and its one-percent-of-the-width scale, for content that sizes itself the same way. */
+internal class GuideScale(val c: IntroColors, val cq: (Float) -> Dp, val cqSp: (Float) -> TextUnit)
+
 private class GuidePage(
     val title: String,
     /** Plain text, or an [AnnotatedString] when part of it needs to stand out. */
@@ -112,8 +118,8 @@ private class GuidePage(
     val command: String? = null,
     val actionLabel: String? = null,
     val onAction: (() -> Unit)? = null,
-    /** Drawn under [explanation]. */
-    val content: (@Composable () -> Unit)? = null,
+    /** Drawn under [explanation], sized off the same screen-width scale as the page. */
+    val content: (@Composable (GuideScale) -> Unit)? = null,
     /** Only shown when the driver picked USB audio on the car audio page. */
     val usbOnly: Boolean = false,
 )
@@ -365,20 +371,24 @@ private fun pages(context: Context, onRequestCallScreening: () -> Unit): List<Gu
         )
     }
 
-    // --- Apps worth installing, once everything above is set up -----------------------
-    if (SHOW_RECOMMENDED_APPS) {
-        add(
-            GuidePage(
-                title = "Good company.",
-                explanation = RECOMMENDED_INTRO,
-                icon = { StarIcon(it) },
-                content = { RecommendedAppsList() },
-            ),
-        )
-    }
-
-    // --- The very end, every time: usage notes. On a replay, the switch shows what was
-    // chosen before.
+    // --- At the end, every time: apps worth installing, how the car's buttons look, and last
+    // the usage notes. On a replay, the switch shows what was chosen before.
+    add(
+        GuidePage(
+            title = "Good company.",
+            explanation = RECOMMENDED_INTRO,
+            icon = { StarIcon(it) },
+            content = { RecommendedAppsList() },
+        ),
+    )
+    add(
+        GuidePage(
+            title = "Your buttons.",
+            explanation = "Pick how the car's buttons look. Change it any time in the car's settings.",
+            icon = { ButtonsIcon(it) },
+            content = { ThemePicker(it.c, it.cq, it.cqSp, key = "guide-buttons") },
+        ),
+    )
     add(usageNotesPage(context))
 }
 
@@ -417,7 +427,7 @@ private fun AudioChoice() {
         ) { CarSettings.setPipeAudio(false) }
         AudioCard(
             "USB", null,
-            "Clearer sound with no delay. Android asks to share audio once each drive.",
+            "Clearer sound with no delay. Each drive, Android asks you to share your screen, which lets Gearslip send the sound.",
             selected = usb,
         ) { CarSettings.setPipeAudio(true) }
     }
@@ -509,10 +519,11 @@ fun SetupGuideScreen(onRequestCallScreening: () -> Unit, onDone: () -> Unit, onl
             // pushes them off the screen. Short pages sit in the middle.
             BoxWithConstraints(Modifier.weight(1f).fillMaxWidth()) {
                 key(index) {
+                    val scroll = rememberScrollState()
                     Column(
                         Modifier
                             .fillMaxWidth()
-                            .verticalScroll(rememberScrollState())
+                            .verticalScroll(scroll)
                             .heightIn(min = maxHeight)
                             .padding(vertical = cq(6f)),
                         verticalArrangement = Arrangement.Center,
@@ -550,7 +561,7 @@ fun SetupGuideScreen(onRequestCallScreening: () -> Unit, onDone: () -> Unit, onl
                                 style = TextStyle(fontSize = cqSp(4.5f), lineHeight = cqSp(6.5f)),
                             )
                             page.command?.let { CopyableCommand(it) }
-                            page.content?.invoke()
+                            page.content?.invoke(GuideScale(c, ::cq, ::cqSp))
                             if (page.permissions != null && alreadyGranted) {
                                 Text(
                                     "Already allowed.", color = c.primary,
@@ -559,6 +570,9 @@ fun SetupGuideScreen(onRequestCallScreening: () -> Unit, onDone: () -> Unit, onl
                             }
                         }
                     }
+                    // A long page (the app list, the usage notes) says so: a fade over the
+                    // last lines and a nudge to keep going, until the bottom is in view.
+                    if (scroll.canScrollForward) ScrollHint(c, ::cq, ::cqSp, Modifier.align(Alignment.BottomCenter))
                 }
             }
 
@@ -585,6 +599,28 @@ fun SetupGuideScreen(onRequestCallScreening: () -> Unit, onDone: () -> Unit, onl
     }
 }
 
+/** A fade into the page's background with "Scroll for more" over it, at the bottom of a page that goes on. */
+@Composable
+private fun ScrollHint(c: IntroColors, cq: (Float) -> Dp, cqSp: (Float) -> TextUnit, modifier: Modifier = Modifier) {
+    val bob by rememberInfiniteTransition(label = "hint").animateFloat(
+        0f, 1f, infiniteRepeatable(tween(900, easing = FastOutSlowInEasing), RepeatMode.Reverse), label = "bob",
+    )
+    Box(
+        modifier
+            .fillMaxWidth()
+            .height(cq(22f))
+            .background(androidx.compose.ui.graphics.Brush.verticalGradient(listOf(c.surface.copy(alpha = 0f), c.surface))),
+        contentAlignment = Alignment.BottomCenter,
+    ) {
+        Text(
+            "Scroll for more  ↓",
+            color = c.primary,
+            style = TextStyle(fontSize = cqSp(4f), fontWeight = FontWeight.Bold),
+            modifier = Modifier.padding(bottom = cq(2f)).offset(y = cq(1.2f) * bob),
+        )
+    }
+}
+
 internal enum class PillStyle { FILLED, OUTLINED, TEXT }
 
 /** The intro's rounded buttons: filled for the step's main action, outlined beside it, bare text to skip. */

gearslip/src/main/java/app/seb3thehacker/gearslip/ui/WirelessButton.kt

@@ -109,6 +109,8 @@ internal fun WirelessButton() {
                                 .clickable {
                                     devices = null
                                     WirelessLink.start(context, device)
+                                    // Next time this car connects, Gearslip does this by itself.
+                                    app.seb3thehacker.gearslip.wireless.WirelessAuto.connectedByHand(context, device)
                                 }
                                 .padding(vertical = 14.dp),
                         )

gearslip/src/main/java/app/seb3thehacker/gearslip/wireless/CarPresenceService.kt

@@ -0,0 +1,15 @@
+package app.seb3thehacker.gearslip.wireless
+
+import android.companion.CompanionDeviceService
+
+/** Android calls this when a car approved in [WirelessAuto] connects over Bluetooth. */
+class CarPresenceService : CompanionDeviceService() {
+
+    @Deprecated("Deprecated in Java")
+    override fun onDeviceAppeared(address: String) {
+        WirelessAuto.carAppeared(applicationContext, address)
+    }
+
+    @Deprecated("Deprecated in Java")
+    override fun onDeviceDisappeared(address: String) {}
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/wireless/WirelessAuto.kt

@@ -0,0 +1,116 @@
+package app.seb3thehacker.gearslip.wireless
+
+import android.annotation.SuppressLint
+import android.bluetooth.BluetoothDevice
+import android.companion.AssociationRequest
+import android.companion.BluetoothDeviceFilter
+import android.companion.CompanionDeviceManager
+import android.content.Context
+import android.content.Intent
+import android.content.IntentSender
+import android.os.Handler
+import android.os.Looper
+import app.seb3thehacker.gearslip.GearslipLog
+import app.seb3thehacker.gearslip.GearslipActivity
+
+/**
+ * Starts wireless Android Auto by itself when a car Gearslip has connected to before comes up
+ * over Bluetooth.
+ *
+ * Android only lets an app wake up and open its screen from the background for a device it
+ * manages as a companion, so the first wireless connection to a car also asks Android to make
+ * that car Gearslip's companion. Android shows its own one-time "Allow" for it; after that it
+ * tells [CarPresenceService] whenever the car connects, and Gearslip connects to it.
+ */
+object WirelessAuto {
+
+    /** Action on the activity's intent when the car came up on its own. */
+    const val ACTION_CAR_NEARBY = "app.seb3thehacker.gearslip.CAR_NEARBY"
+    const val EXTRA_ADDRESS = "address"
+
+    private const val PREFS = "gearslip_wireless_auto"
+
+    private val log = GearslipLog.tagged("AAW")
+
+    /** Set by the activity: shows Android's companion dialog, which only an activity can do. */
+    @Volatile var showApproval: ((IntentSender, String) -> Unit)? = null
+
+    /**
+     * Called whenever the driver connects to [device] by hand. Asks Android once per car; a car
+     * already approved only has its presence watched again, in case Android forgot. A car only
+     * counts as asked once the driver has answered the dialog: if it never showed, the next
+     * connection by hand asks again.
+     */
+    @SuppressLint("MissingPermission")
+    fun connectedByHand(context: Context, device: BluetoothDevice) {
+        val manager = context.getSystemService(CompanionDeviceManager::class.java) ?: return
+        val address = device.address
+        if (isCompanion(manager, address)) {
+            watch(context, address)
+            return
+        }
+        if (context.getSharedPreferences(PREFS, Context.MODE_PRIVATE).getBoolean(address, false)) {
+            log.i("auto-connect: already asked about this car and it was declined; connect by hand")
+            return
+        }
+
+        val request = AssociationRequest.Builder()
+            .addDeviceFilter(BluetoothDeviceFilter.Builder().setAddress(address).build())
+            .setSingleDevice(true)
+            .build()
+        log.i("auto-connect: asking Android to let Gearslip watch for ${WirelessLink.name(device)}")
+        @Suppress("DEPRECATION")
+        manager.associate(request, object : CompanionDeviceManager.Callback() {
+            @Deprecated("Deprecated in Java")
+            override fun onDeviceFound(chooser: IntentSender) {
+                showApproval?.invoke(chooser, address) ?: log.w("auto-connect: no screen to ask on")
+            }
+
+            override fun onFailure(error: CharSequence?) {
+                log.w("auto-connect: Android wouldn't ask ($error)")
+            }
+        }, Handler(Looper.getMainLooper()))
+    }
+
+    /** The driver allowed it in Android's dialog. */
+    fun approved(context: Context, address: String) {
+        log.i("auto-connect: allowed")
+        answered(context, address)
+        watch(context, address)
+    }
+
+    /** The driver said no in Android's dialog: this car isn't asked about again. */
+    fun declined(context: Context, address: String) {
+        log.w("auto-connect: declined in Android's dialog")
+        answered(context, address)
+    }
+
+    private fun answered(context: Context, address: String) {
+        context.getSharedPreferences(PREFS, Context.MODE_PRIVATE).edit().putBoolean(address, true).apply()
+    }
+
+    @SuppressLint("MissingPermission")
+    private fun watch(context: Context, address: String) {
+        val manager = context.getSystemService(CompanionDeviceManager::class.java) ?: return
+        @Suppress("DEPRECATION")
+        runCatching { manager.startObservingDevicePresence(address) }
+            .onFailure { log.w("auto-connect: couldn't watch for the car (${it.message})") }
+    }
+
+    @Suppress("DEPRECATION")
+    private fun isCompanion(manager: CompanionDeviceManager, address: String): Boolean =
+        runCatching { manager.associations.any { it.equals(address, ignoreCase = true) } }.getOrDefault(false)
+
+    /** From [CarPresenceService]: the car is here, so bring Gearslip up to connect to it. */
+    fun carAppeared(context: Context, address: String) {
+        log.i("auto-connect: a car Gearslip knows connected over Bluetooth")
+        runCatching {
+            context.startActivity(
+                Intent(context, GearslipActivity::class.java)
+                    .setAction(ACTION_CAR_NEARBY)
+                    .putExtra(EXTRA_ADDRESS, address)
+                    .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK),
+            )
+        }.onFailure { log.w("auto-connect: couldn't open Gearslip (${it.message})") }
+    }
+}

gearslip/src/main/java/app/seb3thehacker/gearslip/wireless/WirelessLink.kt

@@ -82,8 +82,13 @@ object WirelessLink {
     @Volatile private var tcp: Socket? = null
     @Volatile private var network: ConnectivityManager.NetworkCallback? = null
     @Volatile private var worker: Thread? = null
+
+    /** A start-up or a session's Bluetooth channel is under way. */
+    val busy: Boolean get() = worker?.isAlive == true
     /** Set when Android drops the car's network mid-try, so the rest don't bind to a dead one. */
     @Volatile private var lostNetwork: Network? = null
+    /** The car network asked for or joined, until Android says it's gone or never came. */
+    @Volatile private var activeSsid: String? = null
     /** Bumped on each Wi-Fi join and on stop, so an older run of TCP tries ends instead of racing the new one. */
     @Volatile private var tcpRun = 0
     private val writeLock = Any()
@@ -128,6 +133,7 @@ object WirelessLink {
             runCatching { context.getSystemService(ConnectivityManager::class.java).unregisterNetworkCallback(cb) }
         }
         network = null
+        activeSsid = null
         // Stopped before the car's session began, so nothing else resets Home's card.
         if (starting) {
             log.i("wireless start-up stopped")
@@ -220,6 +226,14 @@ object WirelessLink {
                         val bssid = text(3)
                         val security = Wire.varint(f, 4) ?: -1
                         log.i("<- InfoResponse: ssid=\"$ssid\" bssid=$bssid security=$security password=${if (password.isEmpty()) "none" else "(${password.length} chars)"}")
+                        // ZLink head units send the Wi-Fi details again once the stream is up.
+                        // Asking Android for the network again releases the one carrying the
+                        // stream, which aborts its socket; a phone running Android Auto just
+                        // carries on, so the repeat is ignored while that network is in use.
+                        if (ssid == activeSsid) {
+                            log.i("InfoResponse again for \"$ssid\", which the phone is already on - ignoring it")
+                            continue
+                        }
                         val join = { ip: String, port: Int -> joinWifi(context, output, name, ssid, password, bssid, ip, port) }
                         val known = target
                         if (known != null) {
@@ -329,6 +343,7 @@ object WirelessLink {
             }
 
             override fun onUnavailable() {
+                if (activeSsid == ssid) activeSsid = null
                 log.w("Wi-Fi: couldn't join \"$ssid\" (declined, out of range, or wrong password)")
                 runCatching { send(output, MSG_CONNECTION_STATUS, Protobuf.varintField(1, -1)) }
                 SessionStatus.failed(
@@ -353,6 +368,7 @@ object WirelessLink {
 
             override fun onLost(net: Network) {
                 lostNetwork = net
+                if (activeSsid == ssid) activeSsid = null
                 log.w(
                     "Wi-Fi: lost \"$ssid\" - Android dropped the car's network. Picking it by hand " +
                         "in the Wi-Fi list does this; the remaining tries go over the phone's own Wi-Fi",
@@ -361,6 +377,7 @@ object WirelessLink {
         }
         network?.let { runCatching { manager.unregisterNetworkCallback(it) } }
         network = callback
+        activeSsid = ssid
         manager.requestNetwork(request, callback, WIFI_WAIT_MS)
     }
 

gearslip/src/main/res/values/themes.xml

@@ -9,4 +9,12 @@
         <item name="android:windowNoTitle">true</item>
         <item name="windowActionBar">false</item>
     </style>
+
+    <!-- For PermissionActivity: only Android's own permission dialog shows, over whatever was there. -->
+    <style name="Theme.Gearslip.Invisible" parent="Theme.Gearslip">
+        <item name="android:windowIsTranslucent">true</item>
+        <item name="android:windowBackground">@android:color/transparent</item>
+        <item name="android:windowAnimationStyle">@null</item>
+        <item name="android:backgroundDimEnabled">false</item>
+    </style>
 </resources>

gearslip/src/test/java/app/seb3thehacker/gearslip/ConnectionLifecycleTest.kt

@@ -1,5 +1,6 @@
 package app.seb3thehacker.gearslip
 
+import android.view.Surface
 import java.io.ByteArrayInputStream
 import java.io.ByteArrayOutputStream
 import java.io.IOException
@@ -7,17 +8,20 @@ import java.io.InputStream
 import java.nio.ByteBuffer
 import java.util.concurrent.CountDownLatch
 import java.util.concurrent.ExecutorService
+import java.util.concurrent.FutureTask
 import java.util.concurrent.TimeUnit
 import javax.net.ssl.SSLContext
+import org.junit.Assert.assertArrayEquals
 import org.junit.Assert.assertEquals
 import org.junit.Assert.assertTrue
+import org.junit.Assert.assertFalse
 import org.junit.Test
 
 class ConnectionLifecycleTest {
     private val version = message(1, byteArrayOf(0, 1, 0, 3))
 
     private fun message(id: Int, body: ByteArray = byteArrayOf()) = Frames.build(
-        Frames.CHANNEL_CONTROL, false, byteArrayOf(0, id.toByte()) + body,
+        Frames.CHANNEL_CONTROL, false, byteArrayOf((id ushr 8).toByte(), id.toByte()) + body,
     )
 
     private fun hello(): ByteArray {
@@ -41,13 +45,13 @@ class ConnectionLifecycleTest {
     private fun runner(input: InputStream) = GearslipRunner(input, ByteArrayOutputStream(), ::identity)
 
     @Test fun `rejected authentication ignores subsequent success and service discovery in the same read`() {
-        for (status in listOf(-2, -3)) {
+        for (status in listOf(-2, -3, -23, -24)) {
             runner(ByteArrayInputStream(
                 version + hello() + message(4, Protobuf.varintField(1, status.toLong())) +
                     message(4, Protobuf.varintField(1, 0)) + message(6) + version,
             )).run()
             assertEquals(
-                if (status == -2) SessionReport.Category.CERTIFICATE else SessionReport.Category.AUTH,
+                if (status == -3) SessionReport.Category.AUTH else SessionReport.Category.CERTIFICATE,
                 SessionReport.category,
             )
             assertEquals(SessionStatus.Phase.FAILED, SessionStatus.state.value.phase)
@@ -56,14 +60,70 @@ class ConnectionLifecycleTest {
         }
     }
 
+    @Test fun `protocol error terminates setup and ignores later messages`() {
+        for (error in listOf(255, 65535)) {
+            val runner = runner(ByteArrayInputStream(version + message(error) + version + message(6)))
+            runner.run()
+            assertFalse(getField(runner, "running") as Boolean)
+            assertEquals(SessionReport.Category.UNKNOWN, SessionReport.category)
+            assertEquals("Protocol error", SessionStatus.state.value.headline)
+            assertEquals(SessionReport.Stage.VERSIONS, SessionReport.stage)
+        }
+    }
+
+    @Test fun `head unit can end the session before authentication`() {
+        val output = ByteArrayOutputStream()
+        val runner = GearslipRunner(ByteArrayInputStream(version + message(15, Protobuf.varintField(1, 7))), output, ::identity)
+        runner.run()
+        val parser = Frames.Parser()
+        parser.append(output.toByteArray(), output.size())
+        assertEquals(2, requireNotNull(parser.next()).payload[1].toInt())
+        val reply = requireNotNull(parser.next())
+        assertFalse(reply.encrypted)
+        assertArrayEquals(byteArrayOf(0, 16), reply.payload)
+        assertEquals(SessionReport.Category.BYEBYE, SessionReport.category)
+        assertEquals(SessionStatus.Phase.DISCONNECTED, SessionStatus.state.value.phase)
+    }
+
     @Test fun `TLS failure ignores later protocol messages`() {
         val fatalAlert = message(3, byteArrayOf(21, 3, 3, 0, 2, 2, 42))
         runner(ByteArrayInputStream(version + hello() + fatalAlert + version + message(6))).run()
         assertEquals(SessionReport.Category.TLS, SessionReport.category)
-        assertEquals("Head unit rejected the certificate", SessionStatus.state.value.headline)
+        assertEquals("Secure connection failed", SessionStatus.state.value.headline)
         assertTrue(SessionReport.stage < SessionReport.Stage.ACCEPTED)
     }
 
+    @Test fun `local TLS failure ends the session without waiting for peer EOF`() {
+        val input = CountingInput(version + hello())
+        val runner = GearslipRunner(input, ByteArrayOutputStream(), { error("identity unavailable") })
+        runner.run()
+        assertEquals(1, input.reads)
+        assertEquals(SessionReport.Category.TLS, SessionReport.category)
+        assertEquals("Secure connection failed", SessionStatus.state.value.headline)
+        assertTrue((getField(runner, "writer") as ExecutorService).isShutdown)
+    }
+
+    @Test fun `unsupported version sends rejection and ends without waiting for peer EOF`() {
+        val input = CountingInput(message(1, byteArrayOf(0, 0, 0, 9)))
+        val output = ByteArrayOutputStream()
+        val runner = GearslipRunner(input, output, ::identity)
+        runner.run()
+        assertEquals(1, input.reads)
+        val parser = Frames.Parser()
+        parser.append(output.toByteArray(), output.size())
+        val response = requireNotNull(parser.next())
+        assertArrayEquals(byteArrayOf(0, 2) + ProtocolVersion.respond(0, 9).bytes, response.payload)
+        assertEquals("Unsupported protocol", SessionStatus.state.value.headline)
+    }
+
+    private class CountingInput(bytes: ByteArray) : ByteArrayInputStream(bytes) {
+        var reads = 0
+        override fun read(bytes: ByteArray, offset: Int, length: Int): Int {
+            reads++
+            return super.read(bytes, offset, length)
+        }
+    }
+
     @Test fun `authentication success before TLS completes is ignored`() {
         runner(ByteArrayInputStream(version + message(4, Protobuf.varintField(1, 0)))).run()
         assertEquals(SessionReport.Category.TLS, SessionReport.category)
@@ -133,4 +193,64 @@ class ConnectionLifecycleTest {
             assertTrue((field.get(runner) as ExecutorService).isShutdown)
         }
     }
+    @Test fun `ping echoes the full timestamp and optional payload`() {
+        for (payload in listOf(null, byteArrayOf(), byteArrayOf(0, -1, 42))) {
+            val output = ByteArrayOutputStream()
+            val runner = GearslipRunner(ByteArrayInputStream(byteArrayOf()), output, ::identity)
+            val identity = identity()
+            val tls = FutureTask { PhoneTls(identity.keyStore, identity.password) }.apply { run() }
+            setField(runner, "identityTask", tls)
+            val timestamp = 0x1234_5678_9abcL
+            val request = Protobuf.varintField(1, timestamp) + Protobuf.varintField(2, 1) +
+                (payload?.let { Protobuf.bytesField(3, it) } ?: byteArrayOf())
+            val ping = GearslipRunner::class.java.getDeclaredMethod("onPingRequest", ByteArray::class.java)
+                .apply { isAccessible = true }
+            try {
+                ping.invoke(runner, request)
+                val writer = getField(runner, "writer") as ExecutorService
+                writer.shutdown()
+                assertTrue(writer.awaitTermination(2, TimeUnit.SECONDS))
+                val parser = Frames.Parser()
+                parser.append(output.toByteArray(), output.size())
+                val response = requireNotNull(parser.next()).payload
+                assertEquals(12, response[1].toInt())
+                val fields = Wire.fields(response.copyOfRange(2, response.size))
+                assertEquals(timestamp, Wire.varint(fields, 1))
+                assertArrayEquals(payload, Wire.bytes(fields, 2))
+            } finally {
+                runner.stop()
+            }
+        }
+    }
+
+    private fun getField(runner: GearslipRunner, name: String): Any? =
+        GearslipRunner::class.java.getDeclaredField(name).apply { isAccessible = true }.get(runner)
+
+    private fun setField(runner: GearslipRunner, name: String, value: Any) {
+        GearslipRunner::class.java.getDeclaredField(name).apply { isAccessible = true }.set(runner, value)
+    }
+
+
+    @Test fun `touchpad reports are not injected as touchscreen taps`() {
+        var touches = 0
+        val projection = object : Projection {
+            override fun onSurfaceReady(surface: Surface, width: Int, height: Int, densityDpi: Int) = Unit
+            override fun onTouch(action: Int, actionIndex: Int, points: List<TouchPoint>) { touches++ }
+            override fun onProjectionStopped() = Unit
+        }
+        val runner = GearslipRunner(ByteArrayInputStream(byteArrayOf()), ByteArrayOutputStream(), ::identity, projection)
+        val input = GearslipRunner::class.java.getDeclaredMethod("onInputReport", ByteArray::class.java)
+            .apply { isAccessible = true }
+        val touch = Protobuf.bytesField(1, Protobuf.varintField(1, 100) +
+            Protobuf.varintField(2, 200) + Protobuf.varintField(3, 0))
+        try {
+            input.invoke(runner, Protobuf.varintField(1, 1000) + Protobuf.bytesField(7, touch))
+            assertEquals(0, touches)
+            input.invoke(runner, Protobuf.varintField(1, 1000) + Protobuf.bytesField(3, touch))
+            assertEquals(1, touches)
+        } finally {
+            runner.stop()
+        }
+    }
+
 }

gearslip/src/test/java/app/seb3thehacker/gearslip/CryptoTest.kt

@@ -1,5 +1,6 @@
 package app.seb3thehacker.gearslip
 
+import org.junit.Assert.assertFalse
 import org.junit.Assert.assertEquals
 import org.junit.Assert.assertTrue
 import org.junit.Test
@@ -42,6 +43,14 @@ class CryptoTest {
         assertTrue(TlsSelfTest.run(identity))
     }
 
+    @Test
+    fun `TLS still connects a head unit that presents no certificate, as homemade ones may`() {
+        val generated = SelfSignedCert.generate()
+        val identity = CertProvider.Identity(generated.keyStore, generated.certificate,
+            SelfSignedCert.PASSWORD, "test")
+        assertTrue(TlsSelfTest.run(identity, withClientCertificate = false))
+    }
+
     @Test
     fun `frames round-trip through the parser`() {
         val payload = ByteArray(300) { it.toByte() }

gearslip/src/test/java/app/seb3thehacker/gearslip/FramingTest.kt

@@ -0,0 +1,94 @@
+package app.seb3thehacker.gearslip
+
+import java.io.ByteArrayOutputStream
+import java.io.IOException
+import org.junit.Assert.*
+import org.junit.Test
+
+class FramingTest {
+    @Test fun `fragmentation survives every byte arriving separately`() {
+        val message = ByteArray(40_000) { it.toByte() }
+        val output = ByteArrayOutputStream()
+        assertEquals(3, Frames.writeMessage(output, 5, false, Frames.MESSAGE_SPECIFIC, message) { error("plaintext") })
+        val parser = Frames.Parser()
+        val assembler = Frames.Assembler()
+        var received: ByteArray? = null
+        for (byte in output.toByteArray()) {
+            parser.append(byteArrayOf(byte), 1)
+            parser.next()?.let { received = assembler.offer(it, it.payload) }
+        }
+        assertArrayEquals(message, received)
+    }
+
+    @Test fun `encrypted fragments count plaintext length and encrypt each chunk`() {
+        val output = ByteArrayOutputStream()
+        val message = ByteArray(20_000) { 42 }
+        Frames.writeMessage(output, 1, true, Frames.MESSAGE_SPECIFIC, message) { byteArrayOf(99) + it }
+        val parser = Frames.Parser()
+        parser.append(output.toByteArray(), output.size())
+        val first = parser.next()!!
+        val last = parser.next()!!
+        assertEquals(20_000, first.totalSize)
+        assertEquals(16_121, first.payload.size)
+        assertEquals(Frames.TYPE_LAST, last.frameType)
+        val assembler = Frames.Assembler()
+        assertNull(assembler.offer(first, first.payload.drop(1).toByteArray()))
+        assertArrayEquals(message, assembler.offer(last, last.payload.drop(1).toByteArray()))
+    }
+
+    @Test fun `fragment budget includes the short or extended header`() {
+        for (size in listOf(16_124, 16_125, 32_245)) {
+            val output = ByteArrayOutputStream()
+            Frames.writeMessage(output, 1, false, Frames.MESSAGE_SPECIFIC, ByteArray(size)) { error("plaintext") }
+            val parser = Frames.Parser()
+            parser.append(output.toByteArray(), output.size())
+            val first = parser.next()!!
+            if (size == 16_124) {
+                assertEquals(Frames.TYPE_BULK, first.frameType)
+                assertEquals(16_124, first.payload.size)
+            } else {
+                assertEquals(Frames.TYPE_FIRST, first.frameType)
+                assertEquals(size, first.totalSize)
+                assertEquals(16_120, first.payload.size)
+                val next = parser.next()!!
+                if (size == 32_245) {
+                    assertEquals(Frames.TYPE_MIDDLE, next.frameType)
+                    assertEquals(16_124, next.payload.size)
+                    val last = parser.next()!!
+                    assertEquals(Frames.TYPE_LAST, last.frameType)
+                    assertEquals(1, last.payload.size)
+                } else {
+                    assertEquals(Frames.TYPE_LAST, next.frameType)
+                    assertEquals(5, next.payload.size)
+                }
+            }
+            assertNull(parser.next())
+        }
+    }
+
+    @Test fun `channel control messages cannot be fragmented`() {
+        assertThrows(IllegalArgumentException::class.java) {
+            Frames.writeMessage(ByteArrayOutputStream(), 1, false, Frames.MESSAGE_CONTROL, ByteArray(16_125)) { it }
+        }
+    }
+
+    @Test fun `malformed and mismatched fragment runs are rejected`() {
+        val first = Frames.Frame(1, Frames.TYPE_FIRST, true, 0, byteArrayOf(), 4)
+        val last = Frames.Frame(1, Frames.TYPE_LAST, true, 0, byteArrayOf())
+        assertThrows(IOException::class.java) { Frames.Assembler().offer(last, byteArrayOf(1)) }
+        val assembler = Frames.Assembler()
+        assembler.offer(first, byteArrayOf(1, 2))
+        assertThrows(IOException::class.java) { assembler.offer(last, byteArrayOf(3)) }
+        assembler.offer(first, byteArrayOf(1, 2))
+        assertThrows(IOException::class.java) { assembler.offer(last, byteArrayOf(3, 4, 5)) }
+        assembler.offer(first, byteArrayOf(1, 2))
+        assertThrows(IOException::class.java) { assembler.offer(first, byteArrayOf(1, 2)) }
+    }
+
+    @Test fun `oversized declared message is rejected before allocation`() {
+        val parser = Frames.Parser()
+        val frame = byteArrayOf(1, 1, 0, 1, 0x7f, -1, -1, -1, 0)
+        parser.append(frame, frame.size)
+        assertThrows(IOException::class.java) { parser.next() }
+    }
+}

gearslip/src/test/java/app/seb3thehacker/gearslip/ProtobufTest.kt

@@ -0,0 +1,24 @@
+package app.seb3thehacker.gearslip
+
+import org.junit.Assert.*
+import org.junit.Test
+
+class ProtobufTest {
+    @Test fun `malformed suffix invalidates the whole message`() {
+        for (suffix in listOf(byteArrayOf(0), byteArrayOf(18, -1), byteArrayOf(13, 1), byteArrayOf(17, 1))) {
+            assertTrue(Wire.fields(byteArrayOf(8, 2) + suffix).isEmpty())
+            assertNull(Protobuf.readInt32Field(byteArrayOf(8, 2) + suffix, 1))
+        }
+    }
+
+    @Test fun `lengths cannot wrap when narrowed to int`() {
+        val huge = byteArrayOf(18) + Protobuf.varint(0x1_0000_0001) + byteArrayOf(42)
+        assertTrue(Wire.fields(huge).isEmpty())
+    }
+
+    @Test fun `last singular field wins and negative int32 keeps its sign`() {
+        assertEquals(2, Protobuf.readInt32Field(byteArrayOf(8, 1, 8, 2), 1))
+        assertEquals(-3, Protobuf.readInt32Field(Protobuf.varintField(1, -3), 1))
+        assertEquals(8_803_621_255L, Protobuf.readInt64Field(Protobuf.varintField(1, 8_803_621_255L), 1))
+    }
+}

gearslip/src/test/java/app/seb3thehacker/gearslip/ProtocolVersionTest.kt

@@ -0,0 +1,23 @@
+package app.seb3thehacker.gearslip
+
+import org.junit.Assert.*
+import org.junit.Test
+
+class ProtocolVersionTest {
+    @Test fun `advertises supported version to older and newer 1x peers`() {
+        assertArrayEquals(byteArrayOf(0, 1, 0, 7, 0, 0), ProtocolVersion.respond(1, 3).bytes)
+        assertArrayEquals(byteArrayOf(0, 1, 0, 7, 0, 0), ProtocolVersion.respond(1, 7).bytes)
+        assertArrayEquals(byteArrayOf(0, 1, 0, 7, 0, 0), ProtocolVersion.respond(1, 9).bytes)
+    }
+
+    @Test fun `newer head units get the 1x answer they accept`() {
+        assertArrayEquals(byteArrayOf(0, 1, 0, 7, 0, 0), ProtocolVersion.respond(4, 2).bytes)
+        assertArrayEquals(byteArrayOf(0, 1, 0, 7, 0, 0), ProtocolVersion.respond(6, 1).bytes)
+    }
+
+    @Test fun `major version 0 is refused`() {
+        val response = ProtocolVersion.respond(0, 9)
+        assertFalse(response.supported)
+        assertArrayEquals(byteArrayOf(0, 1, 0, 7, -1, -1), response.bytes)
+    }
+}

gearslip/src/test/java/app/seb3thehacker/gearslip/ServiceDiscoveryChannelTest.kt

@@ -0,0 +1,36 @@
+package app.seb3thehacker.gearslip
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNull
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class ServiceDiscoveryChannelTest {
+    private fun service(id: Long, field: Int, payload: ByteArray = byteArrayOf()) =
+        Protobuf.bytesField(1, Protobuf.varintField(1, id) + Protobuf.bytesField(field, payload))
+
+    @Test fun `invalid channel IDs cannot alias the control or another service channel`() {
+        val config = Protobuf.varintField(1, 16000) + Protobuf.varintField(2, 16) + Protobuf.varintField(3, 1)
+        val audio = Protobuf.bytesField(3, config)
+        val microphone = Protobuf.bytesField(2, config)
+        val sensor = Protobuf.bytesField(1, Protobuf.varintField(1, 1))
+        for (id in listOf(-1L, 0L, 256L, 0x1_0000_0001L)) {
+            assertNull(ServiceDiscovery.findMediaStatusChannel(service(id, 9)))
+            assertNull(ServiceDiscovery.findNavStatusService(service(id, 8, Protobuf.varintField(1, 1000))))
+            assertNull(ServiceDiscovery.findVideoService(service(id, 3, Protobuf.bytesField(4, byteArrayOf()))))
+            assertNull(ServiceDiscovery.findInputService(service(id, 4)))
+            assertNull(ServiceDiscovery.findMicService(service(id, 5, microphone)))
+            assertNull(ServiceDiscovery.findSensorService(service(id, 2, sensor)))
+            assertTrue(ServiceDiscovery.findAudioServices(service(id, 3, audio)).isEmpty())
+        }
+        assertEquals(255, ServiceDiscovery.findMediaStatusChannel(service(255, 9)))
+    }
+
+    @Test fun `navigation discovery preserves the requested update interval`() {
+        val navigation = requireNotNull(ServiceDiscovery.findNavStatusService(service(6, 8, Protobuf.varintField(1, 1500))))
+        assertEquals(6, navigation.serviceId)
+        assertEquals(1500, navigation.minimumIntervalMs)
+        assertNull(ServiceDiscovery.findNavStatusService(service(6, 8)))
+        assertNull(ServiceDiscovery.findNavStatusService(service(6, 8, Protobuf.varintField(1, -1))))
+    }
+}

gearslip/src/test/java/app/seb3thehacker/gearslip/car/ClusterNavTest.kt

@@ -0,0 +1,61 @@
+package app.seb3thehacker.gearslip.car
+
+import app.seb3thehacker.gearslip.Protobuf
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.TimeUnit
+import java.util.concurrent.atomic.AtomicInteger
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class ClusterNavTest {
+    @Test fun `head unit minimum interval limits repeated navigation updates`() {
+        val first = CountDownLatch(1)
+        val next = CountDownLatch(1)
+        val count = AtomicInteger()
+        val nav = ClusterNav(6, 1000) { _, _ ->
+            if (count.incrementAndGet() == 1) first.countDown() else next.countDown()
+        }
+        try {
+            nav.onMessage(8, Protobuf.varintField(1, 0))
+            assertTrue(first.await(2, TimeUnit.SECONDS))
+            nav.onMessage(32769, byteArrayOf())
+            assertFalse("the fixed 500ms timer must not override the head unit", next.await(700, TimeUnit.MILLISECONDS))
+            assertTrue(next.await(2, TimeUnit.SECONDS))
+        } finally {
+            nav.stop()
+        }
+    }
+
+    @Test fun `head unit stop pauses updates and start resends current status`() {
+        val messages = mutableListOf<Int>()
+        val nav = ClusterNav(6) { id, _ -> messages += id }
+        // Drive polling synchronously so the test does not depend on a background timer.
+        val running = ClusterNav::class.java.getDeclaredField("running").apply { isAccessible = true }
+        val tick = ClusterNav::class.java.getDeclaredMethod("tick").apply { isAccessible = true }
+        running.set(nav, true)
+        try {
+            tick.invoke(nav)
+            assertEquals(listOf(32771), messages)
+            nav.onMessage(32770, byteArrayOf())
+            tick.invoke(nav)
+            assertEquals(1, messages.size)
+            nav.onMessage(32769, byteArrayOf())
+            tick.invoke(nav)
+            assertEquals(listOf(32771, 32771), messages)
+            nav.stop()
+            tick.invoke(nav)
+            assertEquals(2, messages.size)
+        } finally {
+            nav.stop()
+        }
+    }
+
+    @Test fun `missing channel open status does not start publishing`() {
+        val nav = ClusterNav(6) { _, _ -> error("channel was not accepted") }
+        nav.onMessage(8, byteArrayOf())
+        val running = ClusterNav::class.java.getDeclaredField("running").apply { isAccessible = true }
+        assertFalse(running.getBoolean(nav))
+    }
+}

gearslip/src/test/java/app/seb3thehacker/gearslip/protocol/InputProtocolTest.kt

@@ -0,0 +1,52 @@
+package app.seb3thehacker.gearslip.protocol
+
+import app.seb3thehacker.gearslip.Protobuf
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNull
+import org.junit.Test
+
+class InputProtocolTest {
+    private fun pointer(id: Int) = Protobuf.bytesField(1,
+        Protobuf.varintField(1, 100) + Protobuf.varintField(2, 200) + Protobuf.varintField(3, id.toLong()))
+
+    @Test fun `multitouch preserves pointer IDs and action index`() {
+        val body = pointer(7) + pointer(3) + Protobuf.varintField(2, 1) + Protobuf.varintField(3, 5)
+        val touch = requireNotNull(InputProtocol.touch(body, 800 to 480))
+        assertEquals(5, touch.action)
+        assertEquals(1, touch.actionIndex)
+        assertEquals(listOf(7, 3), touch.points.map { it.id })
+        assertEquals(100f, touch.points[1].x)
+    }
+
+    @Test fun `invalid pointer index is rejected instead of targeting a different finger`() {
+        assertNull(InputProtocol.touch(pointer(0) + Protobuf.varintField(2, 1), null))
+        assertNull(InputProtocol.touch(pointer(0) + Protobuf.varintField(2, -1), null))
+    }
+
+    @Test fun `missing required pointer fields and duplicate IDs are rejected`() {
+        assertNull(InputProtocol.touch(Protobuf.bytesField(1, Protobuf.varintField(1, 20)), null))
+        assertNull(InputProtocol.touch(pointer(1) + pointer(1), null))
+    }
+
+    @Test fun `pointer IDs must fit the Android motion event range`() {
+        for (id in listOf(-1L, 32L, 0x1_0000_0000L)) {
+            val body = Protobuf.bytesField(1, Protobuf.varintField(1, 100) +
+                Protobuf.varintField(2, 200) + Protobuf.varintField(3, id))
+            assertNull(InputProtocol.touch(body, null))
+        }
+        assertEquals(31, requireNotNull(InputProtocol.touch(pointer(31), null)).points.single().id)
+    }
+
+    @Test fun `oversized pointer sets are rejected before constructing motion events`() {
+        val body = (0..32).fold(byteArrayOf()) { bytes, id -> bytes + pointer(id) }
+        assertNull(InputProtocol.touch(body, null))
+    }
+
+    @Test fun `optional touch fields use down and first pointer defaults`() {
+        val touch = requireNotNull(InputProtocol.touch(pointer(0), 50 to 60))
+        assertEquals(0, touch.action)
+        assertEquals(0, touch.actionIndex)
+        assertEquals(49f, touch.points.single().x)
+        assertEquals(59f, touch.points.single().y)
+    }
+}

gradle/libs.versions.toml

@@ -8,7 +8,7 @@ espressoCore = "3.7.0"
 lifecycleRuntimeKtx = "2.10.0"
 activityCompose = "1.13.0"
 composeBom = "2026.05.01"
-carApp = "1.7.0"
+carApp = "1.8.0-rc01"
 appcompat = "1.7.1"
 material = "1.14.0"
 constraintlayout = "2.2.1"