car icons: drop app tints that can't be seen, mark MAPS.ME and MapQuest as working

MAPS.ME tints its map buttons dark grey for dark mode, which vanished on Gearslip's
dark buttons. A tint below 3:1 contrast now falls back to the normal text colour,
as Android Auto does.

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

@@ -5,6 +5,7 @@ import androidx.compose.runtime.produceState
 import androidx.compose.runtime.remember
 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
@@ -468,7 +469,10 @@ internal fun CarGlyph(icon: CarIcon?, modifier: Modifier = Modifier, standard: I
         val white = remember(bitmap) { bitmap.isPlainWhite() }
         // Untinted white artwork is a template-app habit from dark surfaces; it is coloured like
         // text so it stays readable on a light one.
-        val tint = icon?.tint?.color(dark, content) ?: content.takeIf { white }
+        // An app's own tint is kept only if it can be seen: MAPS.ME asks for dark grey on dark
+        // buttons. Android Auto drops colours that fail contrast the same way.
+        val tint = icon?.tint?.color(dark, content)?.takeIf { it.readableOn(content) }
+            ?: content.takeIf { white || icon?.tint != null }
         Image(
             bitmap, contentDescription = null, modifier = modifier,
             colorFilter = tint?.let { ColorFilter.tint(it) },
@@ -661,6 +665,17 @@ internal fun RowItem(row: CarRow, selection: RowSelection? = null, large: Boolea
 /** 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/host/KnownApps.kt

@@ -19,6 +19,7 @@ object KnownApps {
         "com.metrolist.music", // Metrolist: browse, play, works
         "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
     )
 
     fun works(packageName: String): Boolean = packageName in working
@@ -72,7 +73,6 @@ object KnownApps {
      */
     private val partial = setOf(
         "app.vela", // Vela Maps: connects and draws, but rough enough not to call it working yet
-        "com.mapquest.android.ace", // MapQuest: map, search and routing run, but not cleanly
         "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
     )