Add edge extension for ActivityEmbedding Shell transition animation

Refactor the edge extension logic from DefaultTransitionHandler to the
helper class so that we can reuse it for ActivityEmbedding.

Bug: 207070762
Test: manually verify with Settings.
Change-Id: I6a89b549e7b117caae75ceba6df8f41f5c4d4a15

libs/WindowManager/Shell/src/com/android/wm/shell/activityembedding/ActivityEmbeddingAnimationAdapter.java

@@ -130,6 +130,10 @@ class ActivityEmbeddingAnimationAdapter {
         if (!cropRect.intersect(mWholeAnimationBounds)) {
             // Hide the surface when it is outside of the animation area.
             t.setAlpha(mLeash, 0);
+        } else if (mAnimation.hasExtension()) {
+            // Allow the surface to be shown in its original bounds in case we want to use edge
+            // extensions.
+            cropRect.union(mChange.getEndAbsBounds());
         }
 
         // cropRect is in absolute coordinate, so we need to translate it to surface top left.

libs/WindowManager/Shell/src/com/android/wm/shell/activityembedding/ActivityEmbeddingAnimationRunner.java

@@ -21,6 +21,7 @@ import static android.view.WindowManagerPolicyConstants.TYPE_LAYER_OFFSET;
 import static android.window.TransitionInfo.FLAG_IS_BEHIND_STARTING_WINDOW;
 
 import static com.android.wm.shell.transition.TransitionAnimationHelper.addBackgroundToTransition;
+import static com.android.wm.shell.transition.TransitionAnimationHelper.edgeExtendWindow;
 import static com.android.wm.shell.transition.TransitionAnimationHelper.getTransitionBackgroundColorIfSet;
 
 import android.animation.Animator;
@@ -45,6 +46,7 @@ import com.android.wm.shell.transition.Transitions;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Set;
+import java.util.function.Consumer;
 
 /** To run the ActivityEmbedding animations. */
 class ActivityEmbeddingAnimationRunner {
@@ -65,11 +67,32 @@ class ActivityEmbeddingAnimationRunner {
     void startAnimation(@NonNull IBinder transition, @NonNull TransitionInfo info,
             @NonNull SurfaceControl.Transaction startTransaction,
             @NonNull SurfaceControl.Transaction finishTransaction) {
+        // There may be some surface change that we want to apply after the start transaction is
+        // applied to make sure the surface is ready.
+        final List<Consumer<SurfaceControl.Transaction>> postStartTransactionCallbacks =
+                new ArrayList<>();
         final Animator animator = createAnimator(info, startTransaction, finishTransaction,
-                () -> mController.onAnimationFinished(transition));
+                () -> mController.onAnimationFinished(transition), postStartTransactionCallbacks);
+
+        // Start the animation.
+        if (!postStartTransactionCallbacks.isEmpty()) {
+            // postStartTransactionCallbacks require that the start transaction is already
+            // applied to run otherwise they may result in flickers and UI inconsistencies.
+            startTransaction.apply(true /* sync */);
+
+            // Run tasks that require startTransaction to already be applied
+            final SurfaceControl.Transaction t = new SurfaceControl.Transaction();
+            for (Consumer<SurfaceControl.Transaction> postStartTransactionCallback :
+                    postStartTransactionCallbacks) {
+                postStartTransactionCallback.accept(t);
+            }
+            t.apply();
+            animator.start();
+        } else {
             startTransaction.apply();
             animator.start();
         }
+    }
 
     /**
      * Sets transition animation scale settings value.
@@ -85,9 +108,13 @@ class ActivityEmbeddingAnimationRunner {
     Animator createAnimator(@NonNull TransitionInfo info,
             @NonNull SurfaceControl.Transaction startTransaction,
             @NonNull SurfaceControl.Transaction finishTransaction,
-            @NonNull Runnable animationFinishCallback) {
+            @NonNull Runnable animationFinishCallback,
-        final List<ActivityEmbeddingAnimationAdapter> adapters =
+            @NonNull List<Consumer<SurfaceControl.Transaction>> postStartTransactionCallbacks) {
-                createAnimationAdapters(info, startTransaction, finishTransaction);
+        final List<ActivityEmbeddingAnimationAdapter> adapters = createAnimationAdapters(info,
+                startTransaction);
+        addEdgeExtensionIfNeeded(startTransaction, finishTransaction, postStartTransactionCallbacks,
+                adapters);
+        addBackgroundColorIfNeeded(info, startTransaction, finishTransaction, adapters);
         long duration = 0;
         for (ActivityEmbeddingAnimationAdapter adapter : adapters) {
             duration = Math.max(duration, adapter.getDurationHint());
@@ -131,8 +158,7 @@ class ActivityEmbeddingAnimationRunner {
      */
     @NonNull
     private List<ActivityEmbeddingAnimationAdapter> createAnimationAdapters(
-            @NonNull TransitionInfo info, @NonNull SurfaceControl.Transaction startTransaction,
+            @NonNull TransitionInfo info, @NonNull SurfaceControl.Transaction startTransaction) {
-            @NonNull SurfaceControl.Transaction finishTransaction) {
         boolean isChangeTransition = false;
         for (TransitionInfo.Change change : info.getChanges()) {
             if (change.hasFlags(FLAG_IS_BEHIND_STARTING_WINDOW)) {
@@ -148,25 +174,23 @@ class ActivityEmbeddingAnimationRunner {
             return createChangeAnimationAdapters(info, startTransaction);
         }
         if (Transitions.isClosingType(info.getType())) {
-            return createCloseAnimationAdapters(info, startTransaction, finishTransaction);
+            return createCloseAnimationAdapters(info);
         }
-        return createOpenAnimationAdapters(info, startTransaction, finishTransaction);
+        return createOpenAnimationAdapters(info);
     }
 
     @NonNull
     private List<ActivityEmbeddingAnimationAdapter> createOpenAnimationAdapters(
-            @NonNull TransitionInfo info, @NonNull SurfaceControl.Transaction startTransaction,
+            @NonNull TransitionInfo info) {
-            @NonNull SurfaceControl.Transaction finishTransaction) {
+        return createOpenCloseAnimationAdapters(info, true /* isOpening */,
-        return createOpenCloseAnimationAdapters(info, startTransaction, finishTransaction,
+                mAnimationSpec::loadOpenAnimation);
-                true /* isOpening */, mAnimationSpec::loadOpenAnimation);
     }
 
     @NonNull
     private List<ActivityEmbeddingAnimationAdapter> createCloseAnimationAdapters(
-            @NonNull TransitionInfo info, @NonNull SurfaceControl.Transaction startTransaction,
+            @NonNull TransitionInfo info) {
-            @NonNull SurfaceControl.Transaction finishTransaction) {
+        return createOpenCloseAnimationAdapters(info, false /* isOpening */,
-        return createOpenCloseAnimationAdapters(info, startTransaction, finishTransaction,
+                mAnimationSpec::loadCloseAnimation);
-                false /* isOpening */, mAnimationSpec::loadCloseAnimation);
     }
 
     /**
@@ -175,8 +199,7 @@ class ActivityEmbeddingAnimationRunner {
      */
     @NonNull
     private List<ActivityEmbeddingAnimationAdapter> createOpenCloseAnimationAdapters(
-            @NonNull TransitionInfo info, @NonNull SurfaceControl.Transaction startTransaction,
+            @NonNull TransitionInfo info, boolean isOpening,
-            @NonNull SurfaceControl.Transaction finishTransaction, boolean isOpening,
             @NonNull AnimationProvider animationProvider) {
         // We need to know if the change window is only a partial of the whole animation screen.
         // If so, we will need to adjust it to make the whole animation screen looks like one.
@@ -200,8 +223,7 @@ class ActivityEmbeddingAnimationRunner {
         final List<ActivityEmbeddingAnimationAdapter> adapters = new ArrayList<>();
         for (TransitionInfo.Change change : openingChanges) {
             final ActivityEmbeddingAnimationAdapter adapter = createOpenCloseAnimationAdapter(
-                    info, change, startTransaction, finishTransaction, animationProvider,
+                    info, change, animationProvider, openingWholeScreenBounds);
-                    openingWholeScreenBounds);
             if (isOpening) {
                 adapter.overrideLayer(offsetLayer++);
             }
@@ -209,8 +231,7 @@ class ActivityEmbeddingAnimationRunner {
         }
         for (TransitionInfo.Change change : closingChanges) {
             final ActivityEmbeddingAnimationAdapter adapter = createOpenCloseAnimationAdapter(
-                    info, change, startTransaction, finishTransaction, animationProvider,
+                    info, change, animationProvider, closingWholeScreenBounds);
-                    closingWholeScreenBounds);
             if (!isOpening) {
                 adapter.overrideLayer(offsetLayer++);
             }
@@ -219,20 +240,51 @@ class ActivityEmbeddingAnimationRunner {
         return adapters;
     }
 
+    /** Adds edge extension to the surfaces that have such an animation property. */
+    private void addEdgeExtensionIfNeeded(@NonNull SurfaceControl.Transaction startTransaction,
+            @NonNull SurfaceControl.Transaction finishTransaction,
+            @NonNull List<Consumer<SurfaceControl.Transaction>> postStartTransactionCallbacks,
+            @NonNull List<ActivityEmbeddingAnimationAdapter> adapters) {
+        for (ActivityEmbeddingAnimationAdapter adapter : adapters) {
+            final Animation animation = adapter.mAnimation;
+            if (!animation.hasExtension()) {
+                continue;
+            }
+            final TransitionInfo.Change change = adapter.mChange;
+            if (Transitions.isOpeningType(adapter.mChange.getMode())) {
+                // Need to screenshot after startTransaction is applied otherwise activity
+                // may not be visible or ready yet.
+                postStartTransactionCallbacks.add(
+                        t -> edgeExtendWindow(change, animation, t, finishTransaction));
+            } else {
+                // Can screenshot now (before startTransaction is applied)
+                edgeExtendWindow(change, animation, startTransaction, finishTransaction);
+            }
+        }
+    }
+
+    /** Adds background color to the transition if any animation has such a property. */
+    private void addBackgroundColorIfNeeded(@NonNull TransitionInfo info,
+            @NonNull SurfaceControl.Transaction startTransaction,
+            @NonNull SurfaceControl.Transaction finishTransaction,
+            @NonNull List<ActivityEmbeddingAnimationAdapter> adapters) {
+        for (ActivityEmbeddingAnimationAdapter adapter : adapters) {
+            final int backgroundColor = getTransitionBackgroundColorIfSet(info, adapter.mChange,
+                    adapter.mAnimation, 0 /* defaultColor */);
+            if (backgroundColor != 0) {
+                // We only need to show one color.
+                addBackgroundToTransition(info.getRootLeash(), backgroundColor, startTransaction,
+                        finishTransaction);
+                return;
+            }
+        }
+    }
+
     @NonNull
     private ActivityEmbeddingAnimationAdapter createOpenCloseAnimationAdapter(
             @NonNull TransitionInfo info, @NonNull TransitionInfo.Change change,
-            @NonNull SurfaceControl.Transaction startTransaction,
-            @NonNull SurfaceControl.Transaction finishTransaction,
             @NonNull AnimationProvider animationProvider, @NonNull Rect wholeAnimationBounds) {
         final Animation animation = animationProvider.get(info, change, wholeAnimationBounds);
-        // We may want to show a background color for open/close transition.
-        final int backgroundColor = getTransitionBackgroundColorIfSet(info, change, animation,
-                0 /* defaultColor */);
-        if (backgroundColor != 0) {
-            addBackgroundToTransition(info.getRootLeash(), backgroundColor, startTransaction,
-                    finishTransaction);
-        }
         return new ActivityEmbeddingAnimationAdapter(animation, change, change.getLeash(),
                 wholeAnimationBounds);
     }

libs/WindowManager/Shell/src/com/android/wm/shell/activityembedding/ActivityEmbeddingAnimationSpec.java

@@ -181,15 +181,15 @@ class ActivityEmbeddingAnimationSpec {
             @NonNull TransitionInfo.Change change, @NonNull Rect wholeAnimationBounds) {
         final boolean isEnter = Transitions.isOpeningType(change.getMode());
         final Animation animation;
-        // TODO(b/207070762): Implement edgeExtension version
         if (shouldShowBackdrop(info, change)) {
             animation = mTransitionAnimation.loadDefaultAnimationRes(isEnter
                     ? com.android.internal.R.anim.task_fragment_clear_top_open_enter
                     : com.android.internal.R.anim.task_fragment_clear_top_open_exit);
         } else {
+            // Use the same edge extension animation as regular activity open.
             animation = mTransitionAnimation.loadDefaultAnimationRes(isEnter
-                    ? com.android.internal.R.anim.task_fragment_open_enter
+                    ? com.android.internal.R.anim.activity_open_enter
-                    : com.android.internal.R.anim.task_fragment_open_exit);
+                    : com.android.internal.R.anim.activity_open_exit);
         }
         // Use the whole animation bounds instead of the change bounds, so that when multiple change
         // targets are opening at the same time, the animation applied to each will be the same.
@@ -205,15 +205,15 @@ class ActivityEmbeddingAnimationSpec {
             @NonNull TransitionInfo.Change change, @NonNull Rect wholeAnimationBounds) {
         final boolean isEnter = Transitions.isOpeningType(change.getMode());
         final Animation animation;
-        // TODO(b/207070762): Implement edgeExtension version
         if (shouldShowBackdrop(info, change)) {
             animation = mTransitionAnimation.loadDefaultAnimationRes(isEnter
                     ? com.android.internal.R.anim.task_fragment_clear_top_close_enter
                     : com.android.internal.R.anim.task_fragment_clear_top_close_exit);
         } else {
+            // Use the same edge extension animation as regular activity close.
             animation = mTransitionAnimation.loadDefaultAnimationRes(isEnter
-                    ? com.android.internal.R.anim.task_fragment_close_enter
+                    ? com.android.internal.R.anim.activity_close_enter
-                    : com.android.internal.R.anim.task_fragment_close_exit);
+                    : com.android.internal.R.anim.activity_close_exit);
         }
         // Use the whole animation bounds instead of the change bounds, so that when multiple change
         // targets are closing at the same time, the animation applied to each will be the same.

libs/WindowManager/Shell/src/com/android/wm/shell/transition/DefaultTransitionHandler.java

@@ -59,6 +59,7 @@ import static com.android.internal.policy.TransitionAnimation.WALLPAPER_TRANSITI
 import static com.android.internal.policy.TransitionAnimation.WALLPAPER_TRANSITION_NONE;
 import static com.android.internal.policy.TransitionAnimation.WALLPAPER_TRANSITION_OPEN;
 import static com.android.wm.shell.transition.TransitionAnimationHelper.addBackgroundToTransition;
+import static com.android.wm.shell.transition.TransitionAnimationHelper.edgeExtendWindow;
 import static com.android.wm.shell.transition.TransitionAnimationHelper.getTransitionBackgroundColorIfSet;
 import static com.android.wm.shell.transition.TransitionAnimationHelper.loadAttributeAnimation;
 import static com.android.wm.shell.transition.TransitionAnimationHelper.sDisableCustomTaskAnimationProperty;
@@ -76,10 +77,7 @@ import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
-import android.graphics.Canvas;
 import android.graphics.Insets;
-import android.graphics.Paint;
-import android.graphics.PixelFormat;
 import android.graphics.Point;
 import android.graphics.Rect;
 import android.graphics.drawable.Drawable;
@@ -89,7 +87,6 @@ import android.os.IBinder;
 import android.os.UserHandle;
 import android.util.ArrayMap;
 import android.view.Choreographer;
-import android.view.Surface;
 import android.view.SurfaceControl;
 import android.view.SurfaceSession;
 import android.view.WindowManager;
@@ -97,7 +94,6 @@ import android.view.WindowManager.TransitionType;
 import android.view.animation.AlphaAnimation;
 import android.view.animation.Animation;
 import android.view.animation.Transformation;
-import android.window.ScreenCapture;
 import android.window.TransitionInfo;
 import android.window.TransitionMetrics;
 import android.window.TransitionRequestInfo;
@@ -526,123 +522,6 @@ public class DefaultTransitionHandler implements Transitions.TransitionHandler {
         }
     }
 
-    private void edgeExtendWindow(TransitionInfo.Change change,
-            Animation a, SurfaceControl.Transaction startTransaction,
-            SurfaceControl.Transaction finishTransaction) {
-        // Do not create edge extension surface for transfer starting window change.
-        // The app surface could be empty thus nothing can draw on the hardware renderer, which will
-        // block this thread when calling Surface#unlockCanvasAndPost.
-        if ((change.getFlags() & FLAG_STARTING_WINDOW_TRANSFER_RECIPIENT) != 0) {
-            return;
-        }
-        final Transformation transformationAtStart = new Transformation();
-        a.getTransformationAt(0, transformationAtStart);
-        final Transformation transformationAtEnd = new Transformation();
-        a.getTransformationAt(1, transformationAtEnd);
-
-        // We want to create an extension surface that is the maximal size and the animation will
-        // take care of cropping any part that overflows.
-        final Insets maxExtensionInsets = Insets.min(
-                transformationAtStart.getInsets(), transformationAtEnd.getInsets());
-
-        final int targetSurfaceHeight = Math.max(change.getStartAbsBounds().height(),
-                change.getEndAbsBounds().height());
-        final int targetSurfaceWidth = Math.max(change.getStartAbsBounds().width(),
-                change.getEndAbsBounds().width());
-        if (maxExtensionInsets.left < 0) {
-            final Rect edgeBounds = new Rect(0, 0, 1, targetSurfaceHeight);
-            final Rect extensionRect = new Rect(0, 0,
-                    -maxExtensionInsets.left, targetSurfaceHeight);
-            final int xPos = maxExtensionInsets.left;
-            final int yPos = 0;
-            createExtensionSurface(change.getLeash(), edgeBounds, extensionRect, xPos, yPos,
-                    "Left Edge Extension", startTransaction, finishTransaction);
-        }
-
-        if (maxExtensionInsets.top < 0) {
-            final Rect edgeBounds = new Rect(0, 0, targetSurfaceWidth, 1);
-            final Rect extensionRect = new Rect(0, 0,
-                    targetSurfaceWidth, -maxExtensionInsets.top);
-            final int xPos = 0;
-            final int yPos = maxExtensionInsets.top;
-            createExtensionSurface(change.getLeash(), edgeBounds, extensionRect, xPos, yPos,
-                    "Top Edge Extension", startTransaction, finishTransaction);
-        }
-
-        if (maxExtensionInsets.right < 0) {
-            final Rect edgeBounds = new Rect(targetSurfaceWidth - 1, 0,
-                    targetSurfaceWidth, targetSurfaceHeight);
-            final Rect extensionRect = new Rect(0, 0,
-                    -maxExtensionInsets.right, targetSurfaceHeight);
-            final int xPos = targetSurfaceWidth;
-            final int yPos = 0;
-            createExtensionSurface(change.getLeash(), edgeBounds, extensionRect, xPos, yPos,
-                    "Right Edge Extension", startTransaction, finishTransaction);
-        }
-
-        if (maxExtensionInsets.bottom < 0) {
-            final Rect edgeBounds = new Rect(0, targetSurfaceHeight - 1,
-                    targetSurfaceWidth, targetSurfaceHeight);
-            final Rect extensionRect = new Rect(0, 0,
-                    targetSurfaceWidth, -maxExtensionInsets.bottom);
-            final int xPos = maxExtensionInsets.left;
-            final int yPos = targetSurfaceHeight;
-            createExtensionSurface(change.getLeash(), edgeBounds, extensionRect, xPos, yPos,
-                    "Bottom Edge Extension", startTransaction, finishTransaction);
-        }
-    }
-
-    private SurfaceControl createExtensionSurface(SurfaceControl surfaceToExtend, Rect edgeBounds,
-            Rect extensionRect, int xPos, int yPos, String layerName,
-            SurfaceControl.Transaction startTransaction,
-            SurfaceControl.Transaction finishTransaction) {
-        final SurfaceControl edgeExtensionLayer = new SurfaceControl.Builder()
-                .setName(layerName)
-                .setParent(surfaceToExtend)
-                .setHidden(true)
-                .setCallsite("DefaultTransitionHandler#startAnimation")
-                .setOpaque(true)
-                .setBufferSize(extensionRect.width(), extensionRect.height())
-                .build();
-
-        ScreenCapture.LayerCaptureArgs captureArgs =
-                new ScreenCapture.LayerCaptureArgs.Builder(surfaceToExtend)
-                        .setSourceCrop(edgeBounds)
-                        .setFrameScale(1)
-                        .setPixelFormat(PixelFormat.RGBA_8888)
-                        .setChildrenOnly(true)
-                        .setAllowProtected(true)
-                        .build();
-        final ScreenCapture.ScreenshotHardwareBuffer edgeBuffer =
-                ScreenCapture.captureLayers(captureArgs);
-
-        if (edgeBuffer == null) {
-            ProtoLog.e(ShellProtoLogGroup.WM_SHELL_TRANSITIONS,
-                    "Failed to capture edge of window.");
-            return null;
-        }
-
-        android.graphics.BitmapShader shader =
-                new android.graphics.BitmapShader(edgeBuffer.asBitmap(),
-                        android.graphics.Shader.TileMode.CLAMP,
-                        android.graphics.Shader.TileMode.CLAMP);
-        final Paint paint = new Paint();
-        paint.setShader(shader);
-
-        final Surface surface = new Surface(edgeExtensionLayer);
-        Canvas c = surface.lockHardwareCanvas();
-        c.drawRect(extensionRect, paint);
-        surface.unlockCanvasAndPost(c);
-        surface.release();
-
-        startTransaction.setLayer(edgeExtensionLayer, Integer.MIN_VALUE);
-        startTransaction.setPosition(edgeExtensionLayer, xPos, yPos);
-        startTransaction.setVisibility(edgeExtensionLayer, true);
-        finishTransaction.remove(edgeExtensionLayer);
-
-        return edgeExtensionLayer;
-    }
-
     @Nullable
     @Override
     public WindowContainerTransaction handleRequest(@NonNull IBinder transition,

libs/WindowManager/Shell/src/com/android/wm/shell/transition/TransitionAnimationHelper.java

@@ -24,6 +24,7 @@ import static android.view.WindowManager.TRANSIT_OPEN;
 import static android.view.WindowManager.TRANSIT_TO_BACK;
 import static android.view.WindowManager.TRANSIT_TO_FRONT;
 import static android.view.WindowManager.transitTypeToString;
+import static android.window.TransitionInfo.FLAG_STARTING_WINDOW_TRANSFER_RECIPIENT;
 import static android.window.TransitionInfo.FLAG_TRANSLUCENT;
 
 import static com.android.internal.policy.TransitionAnimation.WALLPAPER_TRANSITION_CLOSE;
@@ -34,10 +35,20 @@ import static com.android.internal.policy.TransitionAnimation.WALLPAPER_TRANSITI
 import android.annotation.ColorInt;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
+import android.graphics.BitmapShader;
+import android.graphics.Canvas;
 import android.graphics.Color;
+import android.graphics.Insets;
+import android.graphics.Paint;
+import android.graphics.PixelFormat;
+import android.graphics.Rect;
+import android.graphics.Shader;
 import android.os.SystemProperties;
+import android.view.Surface;
 import android.view.SurfaceControl;
 import android.view.animation.Animation;
+import android.view.animation.Transformation;
+import android.window.ScreenCapture;
 import android.window.TransitionInfo;
 
 import com.android.internal.R;
@@ -217,4 +228,126 @@ public class TransitionAnimationHelper {
                 .show(animationBackgroundSurface);
         finishTransaction.remove(animationBackgroundSurface);
     }
+
+    /**
+     * Adds edge extension surface to the given {@code change} for edge extension animation.
+     */
+    public static void edgeExtendWindow(@NonNull TransitionInfo.Change change,
+            @NonNull Animation a, @NonNull SurfaceControl.Transaction startTransaction,
+            @NonNull SurfaceControl.Transaction finishTransaction) {
+        // Do not create edge extension surface for transfer starting window change.
+        // The app surface could be empty thus nothing can draw on the hardware renderer, which will
+        // block this thread when calling Surface#unlockCanvasAndPost.
+        if ((change.getFlags() & FLAG_STARTING_WINDOW_TRANSFER_RECIPIENT) != 0) {
+            return;
+        }
+        final Transformation transformationAtStart = new Transformation();
+        a.getTransformationAt(0, transformationAtStart);
+        final Transformation transformationAtEnd = new Transformation();
+        a.getTransformationAt(1, transformationAtEnd);
+
+        // We want to create an extension surface that is the maximal size and the animation will
+        // take care of cropping any part that overflows.
+        final Insets maxExtensionInsets = Insets.min(
+                transformationAtStart.getInsets(), transformationAtEnd.getInsets());
+
+        final int targetSurfaceHeight = Math.max(change.getStartAbsBounds().height(),
+                change.getEndAbsBounds().height());
+        final int targetSurfaceWidth = Math.max(change.getStartAbsBounds().width(),
+                change.getEndAbsBounds().width());
+        if (maxExtensionInsets.left < 0) {
+            final Rect edgeBounds = new Rect(0, 0, 1, targetSurfaceHeight);
+            final Rect extensionRect = new Rect(0, 0,
+                    -maxExtensionInsets.left, targetSurfaceHeight);
+            final int xPos = maxExtensionInsets.left;
+            final int yPos = 0;
+            createExtensionSurface(change.getLeash(), edgeBounds, extensionRect, xPos, yPos,
+                    "Left Edge Extension", startTransaction, finishTransaction);
+        }
+
+        if (maxExtensionInsets.top < 0) {
+            final Rect edgeBounds = new Rect(0, 0, targetSurfaceWidth, 1);
+            final Rect extensionRect = new Rect(0, 0,
+                    targetSurfaceWidth, -maxExtensionInsets.top);
+            final int xPos = 0;
+            final int yPos = maxExtensionInsets.top;
+            createExtensionSurface(change.getLeash(), edgeBounds, extensionRect, xPos, yPos,
+                    "Top Edge Extension", startTransaction, finishTransaction);
+        }
+
+        if (maxExtensionInsets.right < 0) {
+            final Rect edgeBounds = new Rect(targetSurfaceWidth - 1, 0,
+                    targetSurfaceWidth, targetSurfaceHeight);
+            final Rect extensionRect = new Rect(0, 0,
+                    -maxExtensionInsets.right, targetSurfaceHeight);
+            final int xPos = targetSurfaceWidth;
+            final int yPos = 0;
+            createExtensionSurface(change.getLeash(), edgeBounds, extensionRect, xPos, yPos,
+                    "Right Edge Extension", startTransaction, finishTransaction);
+        }
+
+        if (maxExtensionInsets.bottom < 0) {
+            final Rect edgeBounds = new Rect(0, targetSurfaceHeight - 1,
+                    targetSurfaceWidth, targetSurfaceHeight);
+            final Rect extensionRect = new Rect(0, 0,
+                    targetSurfaceWidth, -maxExtensionInsets.bottom);
+            final int xPos = maxExtensionInsets.left;
+            final int yPos = targetSurfaceHeight;
+            createExtensionSurface(change.getLeash(), edgeBounds, extensionRect, xPos, yPos,
+                    "Bottom Edge Extension", startTransaction, finishTransaction);
+        }
+    }
+
+    /**
+     * Takes a screenshot of {@code surfaceToExtend}'s edge and extends it for edge extension
+     * animation.
+     */
+    private static SurfaceControl createExtensionSurface(@NonNull SurfaceControl surfaceToExtend,
+            @NonNull Rect edgeBounds, @NonNull Rect extensionRect, int xPos, int yPos,
+            @NonNull String layerName, @NonNull SurfaceControl.Transaction startTransaction,
+            @NonNull SurfaceControl.Transaction finishTransaction) {
+        final SurfaceControl edgeExtensionLayer = new SurfaceControl.Builder()
+                .setName(layerName)
+                .setParent(surfaceToExtend)
+                .setHidden(true)
+                .setCallsite("TransitionAnimationHelper#createExtensionSurface")
+                .setOpaque(true)
+                .setBufferSize(extensionRect.width(), extensionRect.height())
+                .build();
+
+        final ScreenCapture.LayerCaptureArgs captureArgs =
+                new ScreenCapture.LayerCaptureArgs.Builder(surfaceToExtend)
+                        .setSourceCrop(edgeBounds)
+                        .setFrameScale(1)
+                        .setPixelFormat(PixelFormat.RGBA_8888)
+                        .setChildrenOnly(true)
+                        .setAllowProtected(true)
+                        .build();
+        final ScreenCapture.ScreenshotHardwareBuffer edgeBuffer =
+                ScreenCapture.captureLayers(captureArgs);
+
+        if (edgeBuffer == null) {
+            ProtoLog.e(ShellProtoLogGroup.WM_SHELL_TRANSITIONS,
+                    "Failed to capture edge of window.");
+            return null;
+        }
+
+        final BitmapShader shader = new BitmapShader(edgeBuffer.asBitmap(),
+                Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
+        final Paint paint = new Paint();
+        paint.setShader(shader);
+
+        final Surface surface = new Surface(edgeExtensionLayer);
+        final Canvas c = surface.lockHardwareCanvas();
+        c.drawRect(extensionRect, paint);
+        surface.unlockCanvasAndPost(c);
+        surface.release();
+
+        startTransaction.setLayer(edgeExtensionLayer, Integer.MIN_VALUE);
+        startTransaction.setPosition(edgeExtensionLayer, xPos, yPos);
+        startTransaction.setVisibility(edgeExtensionLayer, true);
+        finishTransaction.remove(edgeExtensionLayer);
+
+        return edgeExtensionLayer;
+    }
 }

libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/activityembedding/ActivityEmbeddingAnimationRunnerTests.java

@@ -40,6 +40,8 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.ArgumentCaptor;
 
+import java.util.ArrayList;
+
 /**
  * Tests for {@link ActivityEmbeddingAnimationRunner}.
  *
@@ -62,13 +64,13 @@ public class ActivityEmbeddingAnimationRunnerTests extends ActivityEmbeddingAnim
         final TransitionInfo.Change embeddingChange = createChange();
         embeddingChange.setFlags(FLAG_IN_TASK_WITH_EMBEDDED_ACTIVITY);
         info.addChange(embeddingChange);
-        doReturn(mAnimator).when(mAnimRunner).createAnimator(any(), any(), any(), any());
+        doReturn(mAnimator).when(mAnimRunner).createAnimator(any(), any(), any(), any(), any());
 
         mAnimRunner.startAnimation(mTransition, info, mStartTransaction, mFinishTransaction);
 
         final ArgumentCaptor<Runnable> finishCallback = ArgumentCaptor.forClass(Runnable.class);
         verify(mAnimRunner).createAnimator(eq(info), eq(mStartTransaction), eq(mFinishTransaction),
-                finishCallback.capture());
+                finishCallback.capture(), any());
         verify(mStartTransaction).apply();
         verify(mAnimator).start();
         verifyNoMoreInteractions(mFinishTransaction);
@@ -88,7 +90,8 @@ public class ActivityEmbeddingAnimationRunnerTests extends ActivityEmbeddingAnim
         info.addChange(embeddingChange);
         final Animator animator = mAnimRunner.createAnimator(
                 info, mStartTransaction, mFinishTransaction,
-                () -> mFinishCallback.onTransitionFinished(null /* wct */, null /* wctCB */));
+                () -> mFinishCallback.onTransitionFinished(null /* wct */, null /* wctCB */),
+                new ArrayList());
 
         // The animation should be empty when it is behind starting window.
         assertEquals(0, animator.getDuration());

libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/activityembedding/ActivityEmbeddingAnimationTestBase.java

@@ -56,13 +56,12 @@ abstract class ActivityEmbeddingAnimationTestBase extends ShellTestCase {
     @Mock
     SurfaceControl.Transaction mFinishTransaction;
     @Mock
-    Transitions.TransitionFinishCallback mFinishCallback;
-    @Mock
     Animator mAnimator;
 
     ActivityEmbeddingController mController;
     ActivityEmbeddingAnimationRunner mAnimRunner;
     ActivityEmbeddingAnimationSpec mAnimSpec;
+    Transitions.TransitionFinishCallback mFinishCallback;
 
     @CallSuper
     @Before
@@ -75,9 +74,11 @@ abstract class ActivityEmbeddingAnimationTestBase extends ShellTestCase {
         assertNotNull(mAnimRunner);
         mAnimSpec = mAnimRunner.mAnimationSpec;
         assertNotNull(mAnimSpec);
+        mFinishCallback = (wct, wctCB) -> {};
         spyOn(mController);
         spyOn(mAnimRunner);
         spyOn(mAnimSpec);
+        spyOn(mFinishCallback);
     }
 
     /** Creates a mock {@link TransitionInfo.Change}. */

libs/WindowManager/Shell/tests/unittest/src/com/android/wm/shell/activityembedding/ActivityEmbeddingControllerTests.java

@@ -55,7 +55,7 @@ public class ActivityEmbeddingControllerTests extends ActivityEmbeddingAnimation
     @Before
     public void setup() {
         super.setUp();
-        doReturn(mAnimator).when(mAnimRunner).createAnimator(any(), any(), any(), any());
+        doReturn(mAnimator).when(mAnimRunner).createAnimator(any(), any(), any(), any(), any());
     }
 
     @Test