Reduce switch split flicker on protrait split

Due to insets for tasks would be changed when switch split on
protrait mode, it lead to some flicker.
Attach screenshots before switch and fading out after switch
animation finished to reduce flicker.
Also update animation algorithm to reduce flicker occured when
top to bottom case.

Fix: 240517067
Test: manual
Test: pass existing tests
Change-Id: I66991b40b2ab8f410abcb800e9ca6e80222faa8c

2 files changed, 46 insertions, 20 deletions

diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/common/split/SplitLayout.java b/libs/WindowManager/Shell/src/com/android/wm/shell/common/split/SplitLayout.java
index c2ad1a98d167..5b7d141591ea 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/common/split/SplitLayout.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/common/split/SplitLayout.java
@@ -69,6 +69,7 @@ import com.android.wm.shell.common.InteractionJankMonitorUtils;
 import com.android.wm.shell.common.split.SplitScreenConstants.SplitPosition;
 
 import java.io.PrintWriter;
+import java.util.function.Consumer;
 
 /**
  * Records and handles layout of splits. Helps to calculate proper bounds when configuration or
@@ -599,7 +600,7 @@ public final class SplitLayout implements DisplayInsetsController.OnInsetsChange
 
     /** Swich both surface position with animation. */
     public void splitSwitching(SurfaceControl.Transaction t, SurfaceControl leash1,
-            SurfaceControl leash2, Runnable finishCallback) {
+            SurfaceControl leash2, Consumer<Rect> finishCallback) {
         final boolean isLandscape = isLandscape();
         final Rect insets = getDisplayInsets(mContext);
         insets.set(isLandscape ? insets.left : 0, isLandscape ? 0 : insets.top,
@@ -617,18 +618,13 @@ public final class SplitLayout implements DisplayInsetsController.OnInsetsChange
         distBounds1.offset(-mRootBounds.left, -mRootBounds.top);
         distBounds2.offset(-mRootBounds.left, -mRootBounds.top);
         distDividerBounds.offset(-mRootBounds.left, -mRootBounds.top);
-        // DO NOT move to insets area for smooth animation.
-        distBounds1.set(distBounds1.left, distBounds1.top,
-                distBounds1.right - insets.right, distBounds1.bottom - insets.bottom);
-        distBounds2.set(distBounds2.left + insets.left, distBounds2.top + insets.top,
-                distBounds2.right, distBounds2.bottom);
 
         ValueAnimator animator1 = moveSurface(t, leash1, getRefBounds1(), distBounds1,
-                false /* alignStart */);
+                -insets.left, -insets.top);
         ValueAnimator animator2 = moveSurface(t, leash2, getRefBounds2(), distBounds2,
-                true /* alignStart */);
+                insets.left, insets.top);
         ValueAnimator animator3 = moveSurface(t, getDividerLeash(), getRefDividerBounds(),
-                distDividerBounds, true /* alignStart */);
+                distDividerBounds, 0 /* offsetX */, 0 /* offsetY */);
 
         AnimatorSet set = new AnimatorSet();
         set.playTogether(animator1, animator2, animator3);
@@ -638,14 +634,14 @@ public final class SplitLayout implements DisplayInsetsController.OnInsetsChange
             public void onAnimationEnd(Animator animation) {
                 mDividePosition = dividerPos;
                 updateBounds(mDividePosition);
-                finishCallback.run();
+                finishCallback.accept(insets);
             }
         });
         set.start();
     }
 
     private ValueAnimator moveSurface(SurfaceControl.Transaction t, SurfaceControl leash,
-            Rect start, Rect end, boolean alignStart) {
+            Rect start, Rect end, float offsetX, float offsetY) {
         Rect tempStart = new Rect(start);
         Rect tempEnd = new Rect(end);
         final float diffX = tempEnd.left - tempStart.left;
@@ -661,15 +657,15 @@ public final class SplitLayout implements DisplayInsetsController.OnInsetsChange
             final float distY = tempStart.top + scale * diffY;
             final int width = (int) (tempStart.width() + scale * diffWidth);
             final int height = (int) (tempStart.height() + scale * diffHeight);
-            if (alignStart) {
+            if (offsetX == 0 && offsetY == 0) {
                 t.setPosition(leash, distX, distY);
                 t.setWindowCrop(leash, width, height);
             } else {
-                final int offsetX = width - tempStart.width();
-                final int offsetY = height - tempStart.height();
-                t.setPosition(leash, distX + offsetX, distY + offsetY);
+                final int diffOffsetX = (int) (scale * offsetX);
+                final int diffOffsetY = (int) (scale * offsetY);
+                t.setPosition(leash, distX + diffOffsetX, distY + diffOffsetY);
                 mTempRect.set(0, 0, width, height);
-                mTempRect.offsetTo(-offsetX, -offsetY);
+                mTempRect.offsetTo(-diffOffsetX, -diffOffsetY);
                 t.setCrop(leash, mTempRect);
             }
             t.apply();
diff --git a/libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageCoordinator.java b/libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageCoordinator.java
index e2ac01f7b003..1f496513c1bf 100644
--- a/libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageCoordinator.java
+++ b/libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageCoordinator.java
@@ -115,6 +115,7 @@ import com.android.wm.shell.common.DisplayController;
 import com.android.wm.shell.common.DisplayImeController;
 import com.android.wm.shell.common.DisplayInsetsController;
 import com.android.wm.shell.common.DisplayLayout;
+import com.android.wm.shell.common.ScreenshotUtils;
 import com.android.wm.shell.common.ShellExecutor;
 import com.android.wm.shell.common.SyncTransactionQueue;
 import com.android.wm.shell.common.TransactionPool;
@@ -850,15 +851,44 @@ public class StageCoordinator implements SplitLayout.SplitLayoutHandler,
     void setSideStagePositionAnimated(@SplitPosition int sideStagePosition) {
         if (mSideStagePosition == sideStagePosition) return;
         SurfaceControl.Transaction t = mTransactionPool.acquire();
+        mTempRect1.setEmpty();
         final StageTaskListener topLeftStage =
                 mSideStagePosition == SPLIT_POSITION_TOP_OR_LEFT ? mSideStage : mMainStage;
+        final SurfaceControl topLeftScreenshot = ScreenshotUtils.takeScreenshot(t,
+                topLeftStage.mRootLeash, mTempRect1, Integer.MAX_VALUE - 1);
         final StageTaskListener bottomRightStage =
                 mSideStagePosition == SPLIT_POSITION_TOP_OR_LEFT ? mMainStage : mSideStage;
+        final SurfaceControl bottomRightScreenshot = ScreenshotUtils.takeScreenshot(t,
+                bottomRightStage.mRootLeash, mTempRect1, Integer.MAX_VALUE - 1);
         mSplitLayout.splitSwitching(t, topLeftStage.mRootLeash, bottomRightStage.mRootLeash,
-                () -> {
-                    setSideStagePosition(SplitLayout.reversePosition(mSideStagePosition),
-                            null /* wct */);
-                    mTransactionPool.release(t);
+                insets -> {
+                    WindowContainerTransaction wct = new WindowContainerTransaction();
+                    setSideStagePosition(SplitLayout.reversePosition(mSideStagePosition), wct);
+                    mSyncQueue.queue(wct);
+                    mSyncQueue.runInSync(st -> {
+                        updateSurfaceBounds(mSplitLayout, st, false /* applyResizingOffset */);
+                        st.setPosition(topLeftScreenshot, -insets.left, -insets.top);
+                        st.setPosition(bottomRightScreenshot, insets.left, insets.top);
+
+                        final ValueAnimator va = ValueAnimator.ofFloat(1, 0);
+                        va.addUpdateListener(valueAnimator-> {
+                            final float progress = (float) valueAnimator.getAnimatedValue();
+                            t.setAlpha(topLeftScreenshot, progress);
+                            t.setAlpha(bottomRightScreenshot, progress);
+                            t.apply();
+                        });
+                        va.addListener(new AnimatorListenerAdapter() {
+                            @Override
+                            public void onAnimationEnd(
+                                    @androidx.annotation.NonNull Animator animation) {
+                                t.remove(topLeftScreenshot);
+                                t.remove(bottomRightScreenshot);
+                                t.apply();
+                                mTransactionPool.release(t);
+                            }
+                        });
+                        va.start();
+                    });
                 });
     }