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

GITHUB_CHANGELOG.md

@@ -16,6 +16,9 @@ This is a developer-focused change log:
 * Fix folder navigation (TODO)
 * Enable Material Expressive Folder Expansion animation flag
 * Move to Google Sans Flex font (TODO)
+* Material 3 Expressive Settings (Phase 2, TODO)
+* Better At-a-Glance perceptive wallpaper colour luminance detection
+  * Big word that means Lawnchair will take system default hint bright/dark theme and fallback to luminosity detection for bright/dark mode detection in At a Glance. 
 
 ### 🥞 Snapshot 9 (Development 4 Release 1)
 

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
 }