SystemUI: Add QS brightness slider gradient customization

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>

Author: neobuddy89

core/java/android/provider/Settings.java

@@ -7717,6 +7717,12 @@ public static void setShowGTalkServiceStatusForUser(ContentResolver cr, boolean
          */
         public static final String QS_TILE_GRADIENT = "qs_tile_gradient";
 
+        /**
+         * Gradient on QS brightness slider
+         * @hide
+         */
+        public static final String QS_BRIGHTNESS_SLIDER_GRADIENT = "qs_brightness_slider_gradient";
+
         /**
          * Keys we no longer back up under the current schema, but want to continue to
          * process when restoring historical backup datasets.

packages/SystemUI/src/com/android/systemui/brightness/ui/compose/BrightnessSlider.kt

@@ -73,11 +73,16 @@ import androidx.compose.ui.draw.drawWithCache
 import androidx.compose.ui.draw.drawWithContent
 import androidx.compose.ui.geometry.CornerRadius
 import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.geometry.RoundRect
 import androidx.compose.ui.geometry.Size
+import androidx.compose.ui.graphics.Brush
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.ColorFilter
+import androidx.compose.ui.graphics.Outline
+import androidx.compose.ui.graphics.Path
 import androidx.compose.ui.graphics.asImageBitmap
 import androidx.compose.ui.graphics.drawscope.DrawScope
+import androidx.compose.ui.graphics.drawscope.clipPath
 import androidx.compose.ui.graphics.drawscope.scale
 import androidx.compose.ui.graphics.drawscope.translate
 import androidx.compose.ui.graphics.painter.BitmapPainter
@@ -164,6 +169,9 @@ fun BrightnessSlider(
         else -> Dimensions.SliderTrackRoundedCorner
     }
 
+    val trackShape = RoundedCornerShape(trackCornerDp)
+    val brightnessGradient = brightnessSliderGradient()
+
     var value by remember(gammaValue) { mutableIntStateOf(gammaValue) }
     val animatedValue by
         animateFloatAsState(targetValue = value.toFloat(), label = "BrightnessSliderAnimatedValue")
@@ -188,7 +196,7 @@ fun BrightnessSlider(
         } else {
             null
         }
-    val colors = colors()
+    val colors = colors(brightnessGradient)
 
     // The value state is recreated every time gammaValue changes, so we recreate this derivedState
     // We have to use value as that's the value that changes when the user is dragging (gammaValue
@@ -359,9 +367,31 @@ fun BrightnessSlider(
                                     BrightnessSliderMotionTestKeys.InactiveIconAlpha
                             }
                             .height(TrackHeight)
-                            .drawWithContent {
+                            .drawWithCache {
+
+                                val outline = trackShape.createOutline(size, layoutDirection, this)
+                                val clipPath = outline.asPath()
+
+                                onDrawWithContent {
                                 drawContent()
 
+                                val gradient = brightnessGradient
+                                if (gradient != null) {
+                                    val gapPx = ThumbTrackGapSize.toPx()
+                                    val fraction = sliderState.coercedValueAsFraction
+                                    val activeEnd = (size.width * fraction - gapPx).coerceAtLeast(0f)
+
+                                    if (activeEnd > 0f) {
+                                        clipPath(clipPath) {
+                                            drawRect(
+                                                brush = gradient.brush,
+                                                topLeft = Offset.Zero,
+                                                size = Size(activeEnd.coerceAtMost(size.width), size.height)
+                                            )
+                                        }
+                                    }
+                                }
+
                                 val yOffset = size.height / 2 - IconSize.toSize().height / 2
                                 val activeTrackStart = 0f
                                 val activeTrackEnd =
@@ -393,6 +423,7 @@ fun BrightnessSlider(
                                         iconActiveAlphaAnimatable.value,
                                     )
                                 }
+                                }
                             },
                     trackCornerSize = trackCornerDp,
                     trackInsideCornerSize = 2.dp,
@@ -425,6 +456,14 @@ fun BrightnessSlider(
     }
 }
 
+fun Outline.asPath(): Path {
+    return when (this) {
+        is Outline.Generic -> path
+        is Outline.Rounded -> Path().apply { addRoundRect(roundRect) }
+        is Outline.Rectangle -> Path().apply { addRect(rect) }
+    }
+}
+
 @Composable
 fun rememberSliderShapeMode(): Int {
     val context = LocalContext.current
@@ -465,6 +504,62 @@ fun rememberSliderShapeMode(): Int {
     return shapeMode
 }
 
+private data class BrightnessGradient(
+    val brush: Brush,
+)
+
+@Composable
+private fun rememberSliderGradient(): Boolean {
+    val context = LocalContext.current
+    val contentResolver = context.contentResolver
+
+    fun readEnabled(): Boolean {
+        return try {
+            Settings.System.getIntForUser(
+                contentResolver, Settings.System.QS_BRIGHTNESS_SLIDER_GRADIENT, 0,
+                UserHandle.USER_CURRENT
+            ) != 0
+        } catch (_: Throwable) {
+            false
+        }
+    }
+
+    var enabled by remember { mutableStateOf(readEnabled()) }
+
+    DisposableEffect(contentResolver) {
+        val observer = object : ContentObserver(null) {
+                override fun onChange(selfChange: Boolean) {
+                    enabled = readEnabled()
+                }
+            }
+
+        contentResolver.registerContentObserver(
+            Settings.System.getUriFor(Settings.System.QS_BRIGHTNESS_SLIDER_GRADIENT),
+            false, observer, UserHandle.USER_ALL
+        )
+
+        onDispose {
+            contentResolver.unregisterContentObserver(observer)
+        }
+    }
+
+    return enabled
+}
+
+@Composable
+private fun brightnessSliderGradient(): BrightnessGradient? {
+    if (!rememberSliderGradient()) return null
+
+    val colors = listOf(
+        MaterialTheme.colorScheme.primary,
+        MaterialTheme.colorScheme.secondary
+    )
+
+    return BrightnessGradient(
+        brush = Brush.horizontalGradient(colors)
+    )
+}
+
 private fun Modifier.sliderBackground(color: Color, corner: Dp) = drawWithCache {
     val offsetAround = SliderBackgroundFrameSize.toSize()
     val newSize = Size(size.width + 2 * offsetAround.width, size.height + 2 * offsetAround.height)
@@ -719,9 +814,11 @@ object BrightnessSliderMotionTestKeys {
 }
 
 @Composable
-private fun colors(): SliderColors {
-    return SliderDefaults.colors()
+private fun colors(brightnessGradient: BrightnessGradient?): SliderColors {
+    val base = SliderDefaults.colors()
+    return base
         .copy(
+            activeTrackColor = if (brightnessGradient != null) Color.Transparent else base.activeTrackColor,
             inactiveTrackColor = LocalAndroidColorScheme.current.surfaceEffect1,
             activeTickColor = MaterialTheme.colorScheme.onPrimary,
             inactiveTickColor = MaterialTheme.colorScheme.onSurface,