feat: Better At-a-Glance perceptive wallpaper colour luminance detection

lawnchair/src/app/lawnchair/util/WallpaperUtils.kt

@@ -1,16 +1,24 @@
 package app.lawnchair.util
 
+import android.app.WallpaperColors
 import android.content.Context
-import android.graphics.Color
+import androidx.core.graphics.ColorUtils
 import app.lawnchair.wallpaper.WallpaperColorsCompat
 import app.lawnchair.wallpaper.WallpaperManagerCompat
 
 fun isWallpaperDark(context: Context): Boolean {
     val wallpaperManager = WallpaperManagerCompat.INSTANCE.get(context)
     val colors: WallpaperColorsCompat? = wallpaperManager.wallpaperColors
-    return colors?.primaryColor?.let { argb ->
-        val darkness =
-            1 - (0.299 * Color.red(argb) + 0.587 * Color.green(argb) + 0.114 * Color.blue(argb)) / 255
-        darkness >= 0.5
-    } ?: false
+    if (colors != null) {
+        val hints = colors.colorHints
+        if ((hints and WallpaperColors.HINT_SUPPORTS_DARK_TEXT) != 0) {
+            return false
+        }
+        if ((hints and WallpaperColors.HINT_SUPPORTS_DARK_THEME) != 0) {
+            return true
+        }
+    }
+
+    val primaryColor = colors?.primaryColor ?: return false
+    return ColorUtils.calculateLuminance(primaryColor) < 0.5
 }