Fix clip reveal animation in docked window case

- Move ClipRectTB/LRAnimation to wm package, because that's the only
place we use it.
- Extend ClipRectTBAnimation to combine it with translation animation
so the clipping gets applied after the translation.
- Fix clip reveal transitions when a window is docked.
- Make the docked divider minimizing animations synchronized with clip
reveal animation.

Bug: 27154882
Bug: 22174716

Change-Id: If5c94c777f3b51c6f53f6f34cc261bf3439cfc88
diff --git a/services/core/java/com/android/server/wm/AppTransition.java b/services/core/java/com/android/server/wm/AppTransition.java
index ad12c66..ba9e640 100644
--- a/services/core/java/com/android/server/wm/AppTransition.java
+++ b/services/core/java/com/android/server/wm/AppTransition.java
@@ -46,7 +46,6 @@
 
 import android.annotation.Nullable;
 import android.content.Context;
-import android.content.res.Configuration;
 import android.graphics.Bitmap;
 import android.graphics.Rect;
 import android.os.Debug;
@@ -64,8 +63,6 @@
 import android.view.animation.AnimationSet;
 import android.view.animation.AnimationUtils;
 import android.view.animation.ClipRectAnimation;
-import android.view.animation.ClipRectLRAnimation;
-import android.view.animation.ClipRectTBAnimation;
 import android.view.animation.Interpolator;
 import android.view.animation.PathInterpolator;
 import android.view.animation.ScaleAnimation;
@@ -74,10 +71,11 @@
 import com.android.internal.util.DumpUtils.Dump;
 import com.android.server.AttributeCache;
 import com.android.server.wm.WindowManagerService.H;
+import com.android.server.wm.animation.ClipRectLRAnimation;
+import com.android.server.wm.animation.ClipRectTBAnimation;
 
 import java.io.PrintWriter;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
@@ -136,6 +134,16 @@
     private static final float RECENTS_THUMBNAIL_FADEOUT_FRACTION = 0.5f;
 
     static final int DEFAULT_APP_TRANSITION_DURATION = 336;
+
+    /** Interpolator to be used for animations that respond directly to a touch */
+    static final Interpolator TOUCH_RESPONSE_INTERPOLATOR =
+            new PathInterpolator(0.3f, 0f, 0.1f, 1f);
+
+    /**
+     * Maximum duration for the clip reveal animation. This is used when there is a lot of movement
+     * involved, to make it more understandable.
+     */
+    private static final int MAX_CLIP_REVEAL_TRANSITION_DURATION = 420;
     private static final int THUMBNAIL_APP_TRANSITION_DURATION = 336;
     private static final int THUMBNAIL_APP_TRANSITION_ALPHA_DURATION = 336;
     private static final long APP_TRANSITION_TIMEOUT_MS = 5000;
@@ -200,13 +208,10 @@
     private final Interpolator mFastOutLinearInInterpolator;
     private final Interpolator mClipHorizontalInterpolator = new PathInterpolator(0, 0, 0.4f, 1f);
 
-    /** Interpolator to be used for animations that respond directly to a touch */
-    private final Interpolator mTouchResponseInterpolator =
-            new PathInterpolator(0.3f, 0f, 0.1f, 1f);
-
     private final int mClipRevealTranslationY;
 
     private int mCurrentUserId = 0;
+    private long mLastClipRevealTransitionDuration = DEFAULT_APP_TRANSITION_DURATION;
 
     private final ArrayList<AppTransitionListener> mListeners = new ArrayList<>();
     private final ExecutorService mDefaultExecutor = Executors.newSingleThreadExecutor();
@@ -636,50 +641,101 @@
                 bitmap, new Rect(left, top, left + width, top + height));
     }
 
-    private Animation createClipRevealAnimationLocked(int transit, boolean enter, Rect appFrame) {
+    long getLastClipRevealTransitionDuration() {
+        return mLastClipRevealTransitionDuration;
+    }
+
+    /**
+     * Calculates the duration for the clip reveal animation. If the clip is "cut off", meaning that
+     * the start rect is outside of the target rect, and there is a lot of movement going on.
+     *
+     * @param cutOff whether the start rect was not fully contained by the end rect
+     * @param translationX the total translation the surface moves in x direction
+     * @param translationY the total translation the surfaces moves in y direction
+     * @param displayFrame our display frame
+     *
+     * @return the duration of the clip reveal animation, in milliseconds
+     */
+    private long calculateClipRevealTransitionDuration(boolean cutOff, float translationX,
+            float translationY, Rect displayFrame) {
+        if (!cutOff) {
+            return DEFAULT_APP_TRANSITION_DURATION;
+        }
+        final float fraction = Math.max(Math.abs(translationX) / displayFrame.width(),
+                Math.abs(translationY) / displayFrame.height());
+        return (long) (DEFAULT_APP_TRANSITION_DURATION + fraction *
+                (MAX_CLIP_REVEAL_TRANSITION_DURATION - DEFAULT_APP_TRANSITION_DURATION));
+    }
+
+    private Animation createClipRevealAnimationLocked(int transit, boolean enter, Rect appFrame,
+            Rect displayFrame) {
         final Animation anim;
         if (enter) {
-            // Reveal will expand and move faster in horizontal direction
-
             final int appWidth = appFrame.width();
             final int appHeight = appFrame.height();
+
             // mTmpRect will contain an area around the launcher icon that was pressed. We will
             // clip reveal from that area in the final area of the app.
             getDefaultNextAppTransitionStartRect(mTmpRect);
 
             float t = 0f;
             if (appHeight > 0) {
-                t = (float) mTmpRect.left / appHeight;
+                t = (float) mTmpRect.top / displayFrame.height();
             }
-            int translationY = mClipRevealTranslationY + (int)(appHeight / 7f * t);
-
+            int translationY = mClipRevealTranslationY + (int)(displayFrame.height() / 7f * t);
+            int translationX = 0;
+            int translationYCorrection = translationY;
             int centerX = mTmpRect.centerX();
             int centerY = mTmpRect.centerY();
             int halfWidth = mTmpRect.width() / 2;
             int halfHeight = mTmpRect.height() / 2;
+            int clipStartX = centerX - halfWidth - appFrame.left;
+            int clipStartY = centerY - halfHeight - appFrame.top;
+            boolean cutOff = false;
+
+            // If the starting rectangle is fully or partially outside of the target rectangle, we
+            // need to start the clipping at the edge and then achieve the rest with translation
+            // and extending the clip rect from that edge.
+            if (appFrame.top > centerY - halfHeight) {
+                translationY = (centerY - halfHeight) - appFrame.top;
+                translationYCorrection = 0;
+                clipStartY = 0;
+                cutOff = true;
+            }
+            if (appFrame.left > centerX - halfWidth) {
+                translationX = (centerX - halfWidth) - appFrame.left;
+                clipStartX = 0;
+                cutOff = true;
+            }
+            if (appFrame.right < centerX + halfWidth) {
+                translationX = (centerX + halfWidth) - appFrame.right;
+                clipStartX = appWidth - mTmpRect.width();
+                cutOff = true;
+            }
+            final long duration = calculateClipRevealTransitionDuration(cutOff, translationX,
+                    translationY, displayFrame);
 
             // Clip third of the from size of launch icon, expand to full width/height
             Animation clipAnimLR = new ClipRectLRAnimation(
-                    centerX - halfWidth, centerX + halfWidth, 0, appWidth);
+                    clipStartX, clipStartX + mTmpRect.width(), 0, appWidth);
             clipAnimLR.setInterpolator(mClipHorizontalInterpolator);
-            clipAnimLR.setDuration((long) (DEFAULT_APP_TRANSITION_DURATION / 2.5f));
+            clipAnimLR.setDuration((long) (duration / 2.5f));
 
-            Animation clipAnimTB = new ClipRectTBAnimation(centerY - halfHeight - translationY,
-                    centerY + halfHeight/ 2 - translationY, 0, appHeight);
-            clipAnimTB.setInterpolator(mTouchResponseInterpolator);
-            clipAnimTB.setDuration(DEFAULT_APP_TRANSITION_DURATION);
+            TranslateAnimation translate = new TranslateAnimation(translationX, 0, translationY, 0);
+            translate.setInterpolator(cutOff ? TOUCH_RESPONSE_INTERPOLATOR
+                    : mLinearOutSlowInInterpolator);
+            translate.setDuration(duration);
 
-            // We might be animating entrance of a docked task, so we need the translate to account
-            // for the app frame in which the window will reside. Every other calculation here
-            // is performed as if the window started at 0,0.
-            translationY -= appFrame.top;
-            TranslateAnimation translate = new TranslateAnimation(-appFrame.left, 0, translationY,
-                    0);
-            translate.setInterpolator(mLinearOutSlowInInterpolator);
-            translate.setDuration(DEFAULT_APP_TRANSITION_DURATION);
+            Animation clipAnimTB = new ClipRectTBAnimation(
+                    clipStartY, clipStartY + mTmpRect.height(),
+                    0, appHeight,
+                    translationYCorrection, 0,
+                    mLinearOutSlowInInterpolator);
+            clipAnimTB.setInterpolator(TOUCH_RESPONSE_INTERPOLATOR);
+            clipAnimTB.setDuration(duration);
 
             // Quick fade-in from icon to app window
-            final int alphaDuration = DEFAULT_APP_TRANSITION_DURATION / 4;
+            final long alphaDuration = duration / 4;
             AlphaAnimation alpha = new AlphaAnimation(0.5f, 1);
             alpha.setDuration(alphaDuration);
             alpha.setInterpolator(mLinearOutSlowInInterpolator);
@@ -692,6 +748,7 @@
             set.setZAdjustment(Animation.ZORDER_TOP);
             set.initialize(appWidth, appHeight, appWidth, appHeight);
             anim = set;
+            mLastClipRevealTransitionDuration = duration;
         } else {
             final long duration;
             switch (transit) {
@@ -798,7 +855,7 @@
             // Animation up from the thumbnail to the full screen
             Animation scale = new ScaleAnimation(1f, scaleW, 1f, scaleW,
                     mTmpRect.left + (thumbWidth / 2f), mTmpRect.top + (thumbHeight / 2f));
-            scale.setInterpolator(mTouchResponseInterpolator);
+            scale.setInterpolator(TOUCH_RESPONSE_INTERPOLATOR);
             scale.setDuration(THUMBNAIL_APP_TRANSITION_DURATION);
             Animation alpha = new AlphaAnimation(1f, 0f);
             alpha.setInterpolator(mThumbnailFadeOutInterpolator);
@@ -806,7 +863,7 @@
             final float toX = appRect.left + appRect.width() / 2 -
                     (mTmpRect.left + thumbWidth / 2);
             Animation translate = new TranslateAnimation(0, toX, 0, toY);
-            translate.setInterpolator(mTouchResponseInterpolator);
+            translate.setInterpolator(TOUCH_RESPONSE_INTERPOLATOR);
             translate.setDuration(THUMBNAIL_APP_TRANSITION_DURATION);
 
             // This AnimationSet uses the Interpolators assigned above.
@@ -819,7 +876,7 @@
             // Animation down from the full screen to the thumbnail
             Animation scale = new ScaleAnimation(scaleW, 1f, scaleW, 1f,
                     mTmpRect.left + (thumbWidth / 2f), mTmpRect.top + (thumbHeight / 2f));
-            scale.setInterpolator(mTouchResponseInterpolator);
+            scale.setInterpolator(TOUCH_RESPONSE_INTERPOLATOR);
             scale.setDuration(THUMBNAIL_APP_TRANSITION_DURATION);
             Animation alpha = new AlphaAnimation(0f, 1f);
             alpha.setInterpolator(mThumbnailFadeInInterpolator);
@@ -827,7 +884,7 @@
             final float toX = appRect.left + appRect.width() / 2 -
                     (mTmpRect.left + thumbWidth / 2);
             Animation translate = new TranslateAnimation(toX, 0, toY, 0);
-            translate.setInterpolator(mTouchResponseInterpolator);
+            translate.setInterpolator(TOUCH_RESPONSE_INTERPOLATOR);
             translate.setDuration(THUMBNAIL_APP_TRANSITION_DURATION);
 
             // This AnimationSet uses the Interpolators assigned above.
@@ -839,7 +896,7 @@
 
         }
         return prepareThumbnailAnimationWithDuration(a, appWidth, appRect.height(), 0,
-                mTouchResponseInterpolator);
+                TOUCH_RESPONSE_INTERPOLATOR);
     }
 
     /**
@@ -971,7 +1028,7 @@
         int duration = Math.max(THUMBNAIL_APP_TRANSITION_ALPHA_DURATION,
                 THUMBNAIL_APP_TRANSITION_DURATION);
         return prepareThumbnailAnimationWithDuration(a, appWidth, appHeight, duration,
-                mTouchResponseInterpolator);
+                TOUCH_RESPONSE_INTERPOLATOR);
     }
 
     private Animation createAspectScaledThumbnailEnterFreeformAnimationLocked(Rect frame,
@@ -1223,8 +1280,9 @@
      *                      bigger.
      */
     Animation loadAnimation(WindowManager.LayoutParams lp, int transit, boolean enter,
-            int orientation, Rect frame, Rect insets, @Nullable Rect surfaceInsets,
-            boolean isVoiceInteraction, boolean freeform, int taskId) {
+            int orientation, Rect frame, Rect displayFrame, Rect insets,
+            @Nullable Rect surfaceInsets, boolean isVoiceInteraction, boolean freeform,
+            int taskId) {
         Animation a;
         if (isVoiceInteraction && (transit == TRANSIT_ACTIVITY_OPEN
                 || transit == TRANSIT_TASK_OPEN
@@ -1269,7 +1327,7 @@
                     + " transit=" + appTransitionToString(transit)
                     + " Callers=" + Debug.getCallers(3));
         } else if (mNextAppTransitionType == NEXT_TRANSIT_TYPE_CLIP_REVEAL) {
-            a = createClipRevealAnimationLocked(transit, enter, frame);
+            a = createClipRevealAnimationLocked(transit, enter, frame, displayFrame);
             if (DEBUG_APP_TRANSITIONS || DEBUG_ANIM) Slog.v(TAG,
                     "applyAnimation:"
                             + " anim=" + a + " nextAppTransition=ANIM_CLIP_REVEAL"
diff --git a/services/core/java/com/android/server/wm/DockedStackDividerController.java b/services/core/java/com/android/server/wm/DockedStackDividerController.java
index ec99d1f..d7c1b32 100644
--- a/services/core/java/com/android/server/wm/DockedStackDividerController.java
+++ b/services/core/java/com/android/server/wm/DockedStackDividerController.java
@@ -28,6 +28,7 @@
 import android.view.SurfaceControl;
 import android.view.animation.AnimationUtils;
 import android.view.animation.Interpolator;
+import android.view.animation.PathInterpolator;
 
 import com.android.server.wm.DimLayer.DimLayerUser;
 
@@ -39,6 +40,8 @@
 import static android.view.WindowManager.DOCKED_LEFT;
 import static android.view.WindowManager.DOCKED_RIGHT;
 import static android.view.WindowManager.DOCKED_TOP;
+import static com.android.server.wm.AppTransition.DEFAULT_APP_TRANSITION_DURATION;
+import static com.android.server.wm.AppTransition.TOUCH_RESPONSE_INTERPOLATOR;
 import static com.android.server.wm.WindowManagerDebugConfig.TAG_WITH_CLASS_NAME;
 import static com.android.server.wm.WindowManagerDebugConfig.TAG_WM;
 
@@ -49,8 +52,6 @@
 
     private static final String TAG = TAG_WITH_CLASS_NAME ? "DockedStackDividerController" : TAG_WM;
 
-    private static final long MINIMIZED_DOCK_ANIMATION_DURATION = 400;
-
     private final WindowManagerService mService;
     private final DisplayContent mDisplayContent;
     private final int mDividerWindowWidth;
@@ -71,6 +72,7 @@
     private long mAnimationStartTime;
     private float mAnimationStart;
     private float mAnimationTarget;
+    private long mAnimationDuration;
     private final Interpolator mMinimizedDockInterpolator;
 
     DockedStackDividerController(WindowManagerService service, DisplayContent displayContent) {
@@ -331,6 +333,10 @@
         notifyDockedStackMinimizedChanged(minimized, 0);
     }
 
+    private boolean isAnimationMaximizing() {
+        return mAnimationTarget == 0f;
+    }
+
     public boolean animate(long now) {
         if (!mAnimating) {
             return false;
@@ -339,12 +345,17 @@
         if (!mAnimationStarted) {
             mAnimationStarted = true;
             mAnimationStartTime = now;
+            final long transitionDuration = isAnimationMaximizing()
+                    ? mService.mAppTransition.getLastClipRevealTransitionDuration()
+                    : DEFAULT_APP_TRANSITION_DURATION;
+            mAnimationDuration = (long)
+                    (transitionDuration * mService.getTransitionAnimationScaleLocked());
             notifyDockedStackMinimizedChanged(mMinimizedDock,
-                    MINIMIZED_DOCK_ANIMATION_DURATION);
+                    mAnimationDuration);
         }
-        float t = Math.min(1f, (float) (now - mAnimationStartTime)
-                / MINIMIZED_DOCK_ANIMATION_DURATION);
-        t = mMinimizedDockInterpolator.getInterpolation(t);
+        float t = Math.min(1f, (float) (now - mAnimationStartTime) / mAnimationDuration);
+        t = (isAnimationMaximizing() ? TOUCH_RESPONSE_INTERPOLATOR : mMinimizedDockInterpolator)
+                .getInterpolation(t);
         final TaskStack stack = mDisplayContent.getDockedStackVisibleForUserLocked();
         if (stack != null) {
             final float amount = t * mAnimationTarget + (1 - t) * mAnimationStart;
diff --git a/services/core/java/com/android/server/wm/WindowManagerService.java b/services/core/java/com/android/server/wm/WindowManagerService.java
index b41ff1c..882ac57 100644
--- a/services/core/java/com/android/server/wm/WindowManagerService.java
+++ b/services/core/java/com/android/server/wm/WindowManagerService.java
@@ -2968,6 +2968,8 @@
             // Determine the visible rect to calculate the thumbnail clip
             final WindowState win = atoken.findMainWindow();
             final Rect frame = new Rect(0, 0, width, height);
+            final Rect displayFrame = new Rect(0, 0,
+                    displayInfo.logicalWidth, displayInfo.logicalHeight);
             final Rect insets = new Rect();
             Rect surfaceInsets = null;
             final boolean freeform = win != null && win.inFreeformWorkspace();
@@ -2995,8 +2997,8 @@
                     + " transit=" + AppTransition.appTransitionToString(transit) + " enter=" + enter
                     + " frame=" + frame + " insets=" + insets + " surfaceInsets=" + surfaceInsets);
             Animation a = mAppTransition.loadAnimation(lp, transit, enter,
-                    mCurConfiguration.orientation, frame, insets, surfaceInsets, isVoiceInteraction,
-                    freeform, atoken.mTask.mTaskId);
+                    mCurConfiguration.orientation, frame, displayFrame, insets, surfaceInsets,
+                    isVoiceInteraction, freeform, atoken.mTask.mTaskId);
             if (a != null) {
                 if (DEBUG_ANIM) logWithStack(TAG, "Loaded animation " + a + " for " + atoken);
                 final int containingWidth = frame.width();
diff --git a/services/core/java/com/android/server/wm/animation/ClipRectLRAnimation.java b/services/core/java/com/android/server/wm/animation/ClipRectLRAnimation.java
new file mode 100644
index 0000000..0db4c70
--- /dev/null
+++ b/services/core/java/com/android/server/wm/animation/ClipRectLRAnimation.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License
+ */
+
+package com.android.server.wm.animation;
+
+import android.graphics.Rect;
+import android.view.animation.ClipRectAnimation;
+import android.view.animation.Transformation;
+
+/**
+ * Special case of ClipRectAnimation that animates only the left/right
+ * dimensions of the clip, picking up the other dimensions from whatever is
+ * set on the transform already.
+ *
+ * @hide
+ */
+public class ClipRectLRAnimation extends ClipRectAnimation {
+
+    /**
+     * Constructor. Passes in 0 for Top/Bottom parameters of ClipRectAnimation
+     */
+    public ClipRectLRAnimation(int fromL, int fromR, int toL, int toR) {
+        super(fromL, 0, fromR, 0, toL, 0, toR, 0);
+    }
+
+    /**
+     * Calculates and sets clip rect on given transformation. It uses existing values
+     * on the Transformation for Top/Bottom clip parameters.
+     */
+    @Override
+    protected void applyTransformation(float it, Transformation tr) {
+        Rect oldClipRect = tr.getClipRect();
+        tr.setClipRect(mFromRect.left + (int) ((mToRect.left - mFromRect.left) * it),
+                oldClipRect.top,
+                mFromRect.right + (int) ((mToRect.right - mFromRect.right) * it),
+                oldClipRect.bottom);
+    }
+}
diff --git a/services/core/java/com/android/server/wm/animation/ClipRectTBAnimation.java b/services/core/java/com/android/server/wm/animation/ClipRectTBAnimation.java
new file mode 100644
index 0000000..1f5b1a3
--- /dev/null
+++ b/services/core/java/com/android/server/wm/animation/ClipRectTBAnimation.java
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License
+ */
+
+package com.android.server.wm.animation;
+
+import android.graphics.Rect;
+import android.view.animation.ClipRectAnimation;
+import android.view.animation.Interpolator;
+import android.view.animation.Transformation;
+import android.view.animation.TranslateAnimation;
+
+/**
+ * Special case of ClipRectAnimation that animates only the top/bottom
+ * dimensions of the clip, picking up the other dimensions from whatever is
+ * set on the transform already. In addition to that, information about a vertical translation
+ * animation can be specified so this animation simulates as the clip would be applied after instead
+ * of before applying the translation.
+ */
+public class ClipRectTBAnimation extends ClipRectAnimation {
+
+    private final int mFromTranslateY;
+    private final int mToTranslateY;
+    private final Interpolator mTranslateInterpolator;
+    private float mNormalizedTime;
+
+    /**
+     * Constructor. Passes in 0 for Left/Right parameters of ClipRectAnimation
+     */
+    public ClipRectTBAnimation(int fromT, int fromB, int toT, int toB,
+            int fromTranslateY, int toTranslateY, Interpolator translateInterpolator) {
+        super(0, fromT, 0, fromB, 0, toT, 0, toB);
+        mFromTranslateY = fromTranslateY;
+        mToTranslateY = toTranslateY;
+        mTranslateInterpolator = translateInterpolator;
+    }
+
+    @Override
+    public boolean getTransformation(long currentTime, Transformation outTransformation) {
+
+        // Hack: Because translation animation has a different interpolator, we need to duplicate
+        // code from Animation here and use it to calculate/store the uninterpolated normalized
+        // time.
+        final long startOffset = getStartOffset();
+        final long duration = getDuration();
+        float normalizedTime;
+        if (duration != 0) {
+            normalizedTime = ((float) (currentTime - (getStartTime() + startOffset))) /
+                    (float) duration;
+        } else {
+            // time is a step-change with a zero duration
+            normalizedTime = currentTime < getStartTime() ? 0.0f : 1.0f;
+        }
+        mNormalizedTime = normalizedTime;
+        return super.getTransformation(currentTime, outTransformation);
+    }
+
+    /**
+     * Calculates and sets clip rect on given transformation. It uses existing values
+     * on the Transformation for Left/Right clip parameters.
+     */
+    @Override
+    protected void applyTransformation(float it, Transformation tr) {
+        float translationT = mTranslateInterpolator.getInterpolation(mNormalizedTime);
+        int translation =
+                (int) (mFromTranslateY + (mToTranslateY - mFromTranslateY) * translationT);
+        Rect oldClipRect = tr.getClipRect();
+        tr.setClipRect(oldClipRect.left,
+                mFromRect.top - translation + (int) ((mToRect.top - mFromRect.top) * it),
+                oldClipRect.right,
+                mFromRect.bottom - translation + (int) ((mToRect.bottom - mFromRect.bottom) * it));
+    }
+
+}