diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/transition/DefaultTransitionHandler.java b/libs/WindowManager/Shell/src/com/android/wm/shell/transition/DefaultTransitionHandler.java
index 3a2820ee..1573291 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/transition/DefaultTransitionHandler.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/transition/DefaultTransitionHandler.java
@@ -358,9 +358,12 @@
 
             if (mode == TRANSIT_CHANGE && change.hasFlags(FLAG_IS_DISPLAY)) {
                 if (info.getType() == TRANSIT_CHANGE) {
-                    final int anim = getRotationAnimationHint(change, info, mDisplayController);
+                    int anim = getRotationAnimationHint(change, info, mDisplayController);
                     isSeamlessDisplayChange = anim == ROTATION_ANIMATION_SEAMLESS;
                     if (!(isSeamlessDisplayChange || anim == ROTATION_ANIMATION_JUMPCUT)) {
+                        if (wallpaperTransit != WALLPAPER_TRANSITION_NONE) {
+                            anim |= ScreenRotationAnimation.ANIMATION_HINT_HAS_WALLPAPER;
+                        }
                         startRotationAnimation(startTransaction, change, info, anim, animations,
                                 onAnimFinish);
                         isDisplayRotationAnimationStarted = true;
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/transition/ScreenRotationAnimation.java b/libs/WindowManager/Shell/src/com/android/wm/shell/transition/ScreenRotationAnimation.java
index 5802e2c..b9d11a3 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/transition/ScreenRotationAnimation.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/transition/ScreenRotationAnimation.java
@@ -25,12 +25,9 @@
 import static com.android.wm.shell.transition.Transitions.TAG;
 
 import android.animation.Animator;
-import android.animation.AnimatorListenerAdapter;
-import android.animation.ArgbEvaluator;
 import android.animation.ValueAnimator;
 import android.annotation.NonNull;
 import android.content.Context;
-import android.graphics.Color;
 import android.graphics.Matrix;
 import android.graphics.Rect;
 import android.hardware.HardwareBuffer;
@@ -38,6 +35,7 @@
 import android.view.Surface;
 import android.view.SurfaceControl;
 import android.view.SurfaceControl.Transaction;
+import android.view.animation.AccelerateInterpolator;
 import android.view.animation.Animation;
 import android.view.animation.AnimationUtils;
 import android.window.ScreenCapture;
@@ -74,6 +72,9 @@
  */
 class ScreenRotationAnimation {
     static final int MAX_ANIMATION_DURATION = 10 * 1000;
+    static final int ANIMATION_HINT_HAS_WALLPAPER = 1 << 8;
+    /** It must cover all WindowManager#ROTATION_ANIMATION_*. */
+    private static final int ANIMATION_TYPE_MASK = 0xff;
 
     private final Context mContext;
     private final TransactionPool mTransactionPool;
@@ -81,7 +82,7 @@
     /** The leash of the changing window container. */
     private final SurfaceControl mSurfaceControl;
 
-    private final int mAnimHint;
+    private final int mAnimType;
     private final int mStartWidth;
     private final int mStartHeight;
     private final int mEndWidth;
@@ -98,6 +99,12 @@
     private SurfaceControl mBackColorSurface;
     /** The leash using to animate screenshot layer. */
     private final SurfaceControl mAnimLeash;
+    /**
+     * The container with background color for {@link #mSurfaceControl}. It is only created if
+     * {@link #mSurfaceControl} may be translucent. E.g. visible wallpaper with alpha < 1 (dimmed).
+     * That prevents flickering of alpha blending.
+     */
+    private SurfaceControl mBackEffectSurface;
 
     // The current active animation to move from the old to the new rotated
     // state.  Which animation is run here will depend on the old and new
@@ -115,7 +122,7 @@
             Transaction t, TransitionInfo.Change change, SurfaceControl rootLeash, int animHint) {
         mContext = context;
         mTransactionPool = pool;
-        mAnimHint = animHint;
+        mAnimType = animHint & ANIMATION_TYPE_MASK;
 
         mSurfaceControl = change.getLeash();
         mStartWidth = change.getStartAbsBounds().width();
@@ -170,11 +177,20 @@
                 }
                 hardwareBuffer.close();
             }
+            if ((animHint & ANIMATION_HINT_HAS_WALLPAPER) != 0) {
+                mBackEffectSurface = new SurfaceControl.Builder()
+                        .setCallsite("ShellRotationAnimation").setParent(rootLeash)
+                        .setEffectLayer().setOpaque(true).setName("BackEffect").build();
+                t.reparent(mSurfaceControl, mBackEffectSurface)
+                        .setColor(mBackEffectSurface,
+                                new float[] {mStartLuma, mStartLuma, mStartLuma})
+                        .show(mBackEffectSurface);
+            }
 
             t.setLayer(mAnimLeash, SCREEN_FREEZE_LAYER_BASE);
             t.show(mAnimLeash);
             // Crop the real content in case it contains a larger child layer, e.g. wallpaper.
-            t.setCrop(mSurfaceControl, new Rect(0, 0, mEndWidth, mEndHeight));
+            t.setCrop(getEnterSurface(), new Rect(0, 0, mEndWidth, mEndHeight));
 
             if (!isCustomRotate()) {
                 mBackColorSurface = new SurfaceControl.Builder()
@@ -199,7 +215,12 @@
     }
 
     private boolean isCustomRotate() {
-        return mAnimHint == ROTATION_ANIMATION_CROSSFADE || mAnimHint == ROTATION_ANIMATION_JUMPCUT;
+        return mAnimType == ROTATION_ANIMATION_CROSSFADE || mAnimType == ROTATION_ANIMATION_JUMPCUT;
+    }
+
+    /** Returns the surface which contains the real content to animate enter. */
+    private SurfaceControl getEnterSurface() {
+        return mBackEffectSurface != null ? mBackEffectSurface : mSurfaceControl;
     }
 
     private void setScreenshotTransform(SurfaceControl.Transaction t) {
@@ -260,7 +281,7 @@
         final boolean customRotate = isCustomRotate();
         if (customRotate) {
             mRotateExitAnimation = AnimationUtils.loadAnimation(mContext,
-                    mAnimHint == ROTATION_ANIMATION_JUMPCUT ? R.anim.rotation_animation_jump_exit
+                    mAnimType == ROTATION_ANIMATION_JUMPCUT ? R.anim.rotation_animation_jump_exit
                             : R.anim.rotation_animation_xfade_exit);
             mRotateEnterAnimation = AnimationUtils.loadAnimation(mContext,
                     R.anim.rotation_animation_enter);
@@ -314,7 +335,11 @@
         } else {
             startDisplayRotation(animations, finishCallback, mainExecutor);
             startScreenshotRotationAnimation(animations, finishCallback, mainExecutor);
-            //startColorAnimation(mTransaction, animationScale);
+            if (mBackEffectSurface != null && mStartLuma > 0.1f) {
+                // Animate from the color of background to black for smooth alpha blending.
+                buildLumaAnimation(animations, mStartLuma, 0f /* endLuma */, mBackEffectSurface,
+                        animationScale, finishCallback, mainExecutor);
+            }
         }
 
         return true;
@@ -322,7 +347,7 @@
 
     private void startDisplayRotation(@NonNull ArrayList<Animator> animations,
             @NonNull Runnable finishCallback, @NonNull ShellExecutor mainExecutor) {
-        buildSurfaceAnimation(animations, mRotateEnterAnimation, mSurfaceControl, finishCallback,
+        buildSurfaceAnimation(animations, mRotateEnterAnimation, getEnterSurface(), finishCallback,
                 mTransactionPool, mainExecutor, null /* position */, 0 /* cornerRadius */,
                 null /* clipRect */, false /* isActivity */);
     }
@@ -341,40 +366,17 @@
                 null /* clipRect */, false /* isActivity */);
     }
 
-    private void startColorAnimation(float animationScale, @NonNull ShellExecutor animExecutor) {
-        int colorTransitionMs = mContext.getResources().getInteger(
-                R.integer.config_screen_rotation_color_transition);
-        final float[] rgbTmpFloat = new float[3];
-        final int startColor = Color.rgb(mStartLuma, mStartLuma, mStartLuma);
-        final int endColor = Color.rgb(mEndLuma, mEndLuma, mEndLuma);
-        final long duration = colorTransitionMs * (long) animationScale;
-        final Transaction t = mTransactionPool.acquire();
-
-        final ValueAnimator va = ValueAnimator.ofFloat(0f, 1f);
-        // Animation length is already expected to be scaled.
-        va.overrideDurationScale(1.0f);
-        va.setDuration(duration);
-        va.addUpdateListener(animation -> {
-            final long currentPlayTime = Math.min(va.getDuration(), va.getCurrentPlayTime());
-            final float fraction = currentPlayTime / va.getDuration();
-            applyColor(startColor, endColor, rgbTmpFloat, fraction, mBackColorSurface, t);
-        });
-        va.addListener(new AnimatorListenerAdapter() {
-            @Override
-            public void onAnimationCancel(Animator animation) {
-                applyColor(startColor, endColor, rgbTmpFloat, 1f /* fraction */, mBackColorSurface,
-                        t);
-                mTransactionPool.release(t);
-            }
-
-            @Override
-            public void onAnimationEnd(Animator animation) {
-                applyColor(startColor, endColor, rgbTmpFloat, 1f /* fraction */, mBackColorSurface,
-                        t);
-                mTransactionPool.release(t);
-            }
-        });
-        animExecutor.execute(va::start);
+    private void buildLumaAnimation(@NonNull ArrayList<Animator> animations,
+            float startLuma, float endLuma, SurfaceControl surface, float animationScale,
+            @NonNull Runnable finishCallback, @NonNull ShellExecutor mainExecutor) {
+        final long durationMillis = (long) (mContext.getResources().getInteger(
+                R.integer.config_screen_rotation_color_transition) * animationScale);
+        final LumaAnimation animation = new LumaAnimation(durationMillis);
+        // Align the end with the enter animation.
+        animation.setStartOffset(mRotateEnterAnimation.getDuration() - durationMillis);
+        final LumaAnimationAdapter adapter = new LumaAnimationAdapter(surface, startLuma, endLuma);
+        buildSurfaceAnimation(animations, animation, finishCallback, mTransactionPool,
+                mainExecutor, adapter);
     }
 
     public void kill() {
@@ -389,21 +391,47 @@
         if (mBackColorSurface != null && mBackColorSurface.isValid()) {
             t.remove(mBackColorSurface);
         }
+        if (mBackEffectSurface != null && mBackEffectSurface.isValid()) {
+            t.remove(mBackEffectSurface);
+        }
         t.apply();
         mTransactionPool.release(t);
     }
 
-    private static void applyColor(int startColor, int endColor, float[] rgbFloat,
-            float fraction, SurfaceControl surface, SurfaceControl.Transaction t) {
-        final int color = (Integer) ArgbEvaluator.getInstance().evaluate(fraction, startColor,
-                endColor);
-        Color middleColor = Color.valueOf(color);
-        rgbFloat[0] = middleColor.red();
-        rgbFloat[1] = middleColor.green();
-        rgbFloat[2] = middleColor.blue();
-        if (surface.isValid()) {
-            t.setColor(surface, rgbFloat);
+    /** A no-op wrapper to provide animation duration. */
+    private static class LumaAnimation extends Animation {
+        LumaAnimation(long durationMillis) {
+            setDuration(durationMillis);
         }
-        t.apply();
+    }
+
+    private static class LumaAnimationAdapter extends DefaultTransitionHandler.AnimationAdapter {
+        final float[] mColorArray = new float[3];
+        final float mStartLuma;
+        final float mEndLuma;
+        final AccelerateInterpolator mInterpolation;
+
+        LumaAnimationAdapter(@NonNull SurfaceControl leash, float startLuma, float endLuma) {
+            super(leash);
+            mStartLuma = startLuma;
+            mEndLuma = endLuma;
+            // Make the initial progress color lighter if the background is light. That avoids
+            // darker content when fading into the entering surface.
+            final float factor = Math.min(3f, (Math.max(0.5f, mStartLuma) - 0.5f) * 10);
+            Slog.d(TAG, "Luma=" + mStartLuma + " factor=" + factor);
+            mInterpolation = factor > 0.5f ? new AccelerateInterpolator(factor) : null;
+        }
+
+        @Override
+        void applyTransformation(ValueAnimator animator) {
+            final float fraction = mInterpolation != null
+                    ? mInterpolation.getInterpolation(animator.getAnimatedFraction())
+                    : animator.getAnimatedFraction();
+            final float luma = mStartLuma + fraction * (mEndLuma - mStartLuma);
+            mColorArray[0] = luma;
+            mColorArray[1] = luma;
+            mColorArray[2] = luma;
+            mTransaction.setColor(mLeash, mColorArray);
+        }
     }
 }