Enabling recents stack clipping

The taskviews now avoid overdraw by clipping invisible
parts. Also adapted some timings of the animation.

Bug: 17455301
Change-Id: Ifbf7bab363e530cb2ad842baed50fc16dcfcc4c4

10 files changed, 197 insertions, 48 deletions

diff --git a/packages/SystemUI/src/com/android/systemui/recents/Constants.java b/packages/SystemUI/src/com/android/systemui/recents/Constants.java
index e4a167b..103f96f 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/Constants.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/Constants.java
@@ -32,7 +32,7 @@ public class Constants {
             // Enables the filtering of tasks according to their grouping
             public static final boolean EnableTaskFiltering = false;
             // Enables clipping of tasks against each other
-            public static final boolean EnableTaskStackClipping = false;
+            public static final boolean EnableTaskStackClipping = true;
             // Enables tapping on the TaskBar to launch the task
             public static final boolean EnableTaskBarTouchEvents = true;
             // Enables app-info pane on long-pressing the icon
diff --git a/packages/SystemUI/src/com/android/systemui/recents/RecentsConfiguration.java b/packages/SystemUI/src/com/android/systemui/recents/RecentsConfiguration.java
index e3a2ad8..4696c82 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/RecentsConfiguration.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/RecentsConfiguration.java
@@ -78,6 +78,7 @@ public class RecentsConfiguration {
     public int taskViewEnterFromHomeDelay;
     public int taskViewEnterFromHomeDuration;
     public int taskViewEnterFromHomeStaggerDelay;
+    public int taskViewEnterFromHomeStaggerDuration;
     public int taskViewExitToHomeDuration;
     public int taskViewRemoveAnimDuration;
     public int taskViewRemoveAnimTranslationXPx;
@@ -219,6 +220,8 @@ public class RecentsConfiguration {
                 res.getInteger(R.integer.recents_animate_task_enter_from_home_duration);
         taskViewEnterFromHomeStaggerDelay =
                 res.getInteger(R.integer.recents_animate_task_enter_from_home_stagger_delay);
+        taskViewEnterFromHomeStaggerDuration =
+                res.getInteger(R.integer.recents_animate_task_enter_from_home_stagger_duration);
         taskViewExitToHomeDuration =
                 res.getInteger(R.integer.recents_animate_task_exit_to_home_duration);
         taskViewRemoveAnimDuration =
diff --git a/packages/SystemUI/src/com/android/systemui/recents/misc/Utilities.java b/packages/SystemUI/src/com/android/systemui/recents/misc/Utilities.java
index 4c6b389..f01d17c 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/misc/Utilities.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/misc/Utilities.java
@@ -18,11 +18,14 @@ package com.android.systemui.recents.misc;
 
 import android.content.Intent;
 import android.graphics.Color;
+import android.graphics.Matrix;
 import android.graphics.Rect;
+import android.view.View;
 import com.android.systemui.recents.RecentsConfiguration;
 
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
+import java.util.ArrayList;
 
 /* Common code */
 public class Utilities {
@@ -68,6 +71,80 @@ public class Utilities {
         }
     }
 
+    /** Maps a coorindate in a descendant view into the parent. */
+    public static float mapCoordInDescendentToSelf(View descendant, View root,
+            float[] coord, boolean includeRootScroll) {
+        ArrayList<View> ancestorChain = new ArrayList<View>();
+
+        float[] pt = {coord[0], coord[1]};
+
+        View v = descendant;
+        while(v != root && v != null) {
+            ancestorChain.add(v);
+            v = (View) v.getParent();
+        }
+        ancestorChain.add(root);
+
+        float scale = 1.0f;
+        int count = ancestorChain.size();
+        for (int i = 0; i < count; i++) {
+            View v0 = ancestorChain.get(i);
+            // For TextViews, scroll has a meaning which relates to the text position
+            // which is very strange... ignore the scroll.
+            if (v0 != descendant || includeRootScroll) {
+                pt[0] -= v0.getScrollX();
+                pt[1] -= v0.getScrollY();
+            }
+
+            v0.getMatrix().mapPoints(pt);
+            pt[0] += v0.getLeft();
+            pt[1] += v0.getTop();
+            scale *= v0.getScaleX();
+        }
+
+        coord[0] = pt[0];
+        coord[1] = pt[1];
+        return scale;
+    }
+
+    /** Maps a coordinate in the root to a descendent. */
+    public static float mapCoordInSelfToDescendent(View descendant, View root,
+            float[] coord, Matrix tmpInverseMatrix) {
+        ArrayList<View> ancestorChain = new ArrayList<View>();
+
+        float[] pt = {coord[0], coord[1]};
+
+        View v = descendant;
+        while(v != root) {
+            ancestorChain.add(v);
+            v = (View) v.getParent();
+        }
+        ancestorChain.add(root);
+
+        float scale = 1.0f;
+        int count = ancestorChain.size();
+        tmpInverseMatrix.set(Matrix.IDENTITY_MATRIX);
+        for (int i = count - 1; i >= 0; i--) {
+            View ancestor = ancestorChain.get(i);
+            View next = i > 0 ? ancestorChain.get(i-1) : null;
+
+            pt[0] += ancestor.getScrollX();
+            pt[1] += ancestor.getScrollY();
+
+            if (next != null) {
+                pt[0] -= next.getLeft();
+                pt[1] -= next.getTop();
+                next.getMatrix().invert(tmpInverseMatrix);
+                tmpInverseMatrix.mapPoints(pt);
+                scale *= next.getScaleX();
+            }
+        }
+
+        coord[0] = pt[0];
+        coord[1] = pt[1];
+        return scale;
+    }
+
     /** Calculates the constrast between two colors, using the algorithm provided by the WCAG v2. */
     public static float computeContrastBetweenColors(int bg, int fg) {
         float bgR = Color.red(bg) / 255f;
diff --git a/packages/SystemUI/src/com/android/systemui/recents/views/AnimateableViewBounds.java b/packages/SystemUI/src/com/android/systemui/recents/views/AnimateableViewBounds.java
index b584fd3..d2fdaff 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/views/AnimateableViewBounds.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/AnimateableViewBounds.java
@@ -22,6 +22,7 @@ import android.graphics.Outline;
 import android.graphics.Rect;
 import android.view.View;
 import android.view.ViewOutlineProvider;
+
 import com.android.systemui.recents.RecentsConfiguration;
 
 /* An outline provider that has a clip and outline that can be animated. */
@@ -29,8 +30,10 @@ public class AnimateableViewBounds extends ViewOutlineProvider {
 
     RecentsConfiguration mConfig;
 
-    View mSourceView;
+    TaskView mSourceView;
+    Rect mTmpRect = new Rect();
     Rect mClipRect = new Rect();
+    Rect mClipBounds = new Rect();
     Rect mOutlineClipRect = new Rect();
     int mCornerRadius;
     float mAlpha = 1f;
@@ -40,7 +43,7 @@ public class AnimateableViewBounds extends ViewOutlineProvider {
     ObjectAnimator mClipRightAnimator;
     ObjectAnimator mClipBottomAnimator;
 
-    public AnimateableViewBounds(View source, int cornerRadius) {
+    public AnimateableViewBounds(TaskView source, int cornerRadius) {
         mConfig = RecentsConfiguration.getInstance();
         mSourceView = source;
         mCornerRadius = cornerRadius;
@@ -53,8 +56,6 @@ public class AnimateableViewBounds extends ViewOutlineProvider {
     @Override
     public void getOutline(View view, Outline outline) {
         outline.setAlpha(mMinAlpha + mAlpha / (1f - mMinAlpha));
-
-        // TODO: This doesn't work with fake shadows.
         outline.setRoundRect(Math.max(mClipRect.left, mOutlineClipRect.left),
                 Math.max(mClipRect.top, mOutlineClipRect.top),
                 mSourceView.getWidth() - Math.max(mClipRect.right, mOutlineClipRect.right),
@@ -90,6 +91,7 @@ public class AnimateableViewBounds extends ViewOutlineProvider {
         if (top != mClipRect.top) {
             mClipRect.top = top;
             mSourceView.invalidateOutline();
+            updateClipBounds();
         }
     }
 
@@ -115,6 +117,7 @@ public class AnimateableViewBounds extends ViewOutlineProvider {
         if (right != mClipRect.right) {
             mClipRect.right = right;
             mSourceView.invalidateOutline();
+            updateClipBounds();
         }
     }
 
@@ -140,6 +143,11 @@ public class AnimateableViewBounds extends ViewOutlineProvider {
         if (bottom != mClipRect.bottom) {
             mClipRect.bottom = bottom;
             mSourceView.invalidateOutline();
+            updateClipBounds();
+            if (!mConfig.useHardwareLayers) {
+                mSourceView.mThumbnailView.updateVisibility(
+                        bottom - mSourceView.getPaddingBottom());
+            }
         }
     }
 
@@ -160,4 +168,11 @@ public class AnimateableViewBounds extends ViewOutlineProvider {
     public int getOutlineClipBottom() {
         return mOutlineClipRect.bottom;
     }
+
+    private void updateClipBounds() {
+        mClipBounds.set(mClipRect.left, mClipRect.top,
+                mSourceView.getWidth() - mClipRect.right,
+                mSourceView.getHeight() - mClipRect.bottom);
+        mSourceView.setClipBounds(mClipBounds);
+    }
 }
diff --git a/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackView.java b/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackView.java
index 470b1f0..e1e4068 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackView.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/TaskStackView.java
@@ -16,21 +16,23 @@
 
 package com.android.systemui.recents.views;
 
+import android.animation.ValueAnimator;
 import android.content.ComponentName;
 import android.content.Context;
+import android.graphics.Matrix;
 import android.graphics.Rect;
 import android.view.LayoutInflater;
 import android.view.MotionEvent;
 import android.view.View;
+import android.view.ViewTreeObserver;
 import android.view.accessibility.AccessibilityEvent;
-import android.view.accessibility.AccessibilityManager;
-import android.view.accessibility.AccessibilityNodeInfo;
 import android.widget.FrameLayout;
 import com.android.systemui.R;
 import com.android.systemui.recents.Constants;
 import com.android.systemui.recents.RecentsConfiguration;
 import com.android.systemui.recents.misc.DozeTrigger;
 import com.android.systemui.recents.misc.SystemServicesProxy;
+import com.android.systemui.recents.misc.Utilities;
 import com.android.systemui.recents.model.RecentsPackageMonitor;
 import com.android.systemui.recents.model.RecentsTaskLoader;
 import com.android.systemui.recents.model.Task;
@@ -76,16 +78,28 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
     // Optimizations
     int mStackViewsAnimationDuration;
     boolean mStackViewsDirty = true;
+    boolean mStackViewsClipDirty = true;
     boolean mAwaitingFirstLayout = true;
     boolean mStartEnterAnimationRequestedAfterLayout;
     boolean mStartEnterAnimationCompleted;
     ViewAnimation.TaskViewEnterContext mStartEnterAnimationContext;
     int[] mTmpVisibleRange = new int[2];
+    float[] mTmpCoord = new float[2];
+    Matrix mTmpMatrix = new Matrix();
     Rect mTmpRect = new Rect();
     TaskViewTransform mTmpTransform = new TaskViewTransform();
     HashMap<Task, TaskView> mTmpTaskViewMap = new HashMap<Task, TaskView>();
     LayoutInflater mInflater;
 
+    // A convenience update listener to request updating clipping of tasks
+    ValueAnimator.AnimatorUpdateListener mRequestUpdateClippingListener =
+            new ValueAnimator.AnimatorUpdateListener() {
+        @Override
+        public void onAnimationUpdate(ValueAnimator animation) {
+            requestUpdateStackViewsClip();
+        }
+    };
+
     // A convenience runnable to return all views to the pool
     Runnable mReturnAllViewsToPoolRunnable = new Runnable() {
         @Override
@@ -152,6 +166,14 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
         }
     }
 
+    /** Requests that the views clipping be updated. */
+    void requestUpdateStackViewsClip() {
+        if (!mStackViewsClipDirty) {
+            invalidate();
+            mStackViewsClipDirty = true;
+        }
+    }
+
     /** Finds the child view given a specific task. */
     public TaskView getChildViewForTask(Task t) {
         int childCount = getChildCount();
@@ -301,7 +323,7 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
 
                 // Animate the task into place
                 tv.updateViewPropertiesToTaskTransform(mCurrentTaskTransforms.get(taskIndex),
-                        mStackViewsAnimationDuration);
+                        mStackViewsAnimationDuration, mRequestUpdateClippingListener);
 
                 // Request accessibility focus on the next view if we removed the task
                 // that previously held accessibility focus
@@ -319,6 +341,7 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
             // Reset the request-synchronize params
             mStackViewsAnimationDuration = 0;
             mStackViewsDirty = false;
+            mStackViewsClipDirty = true;
             return true;
         }
         return false;
@@ -349,10 +372,13 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
                     // stacked and we can make assumptions about the visibility of the this
                     // task relative to the ones in front of it.
                     if (nextTv != null) {
-                        // We can reuse the current task transforms to find the task rects
-                        TaskViewTransform transform = mCurrentTaskTransforms.get(mStack.indexOfTask(tv.getTask()));
-                        TaskViewTransform nextTransform = mCurrentTaskTransforms.get(mStack.indexOfTask(nextTv.getTask()));
-                        clipBottom = transform.rect.bottom - nextTransform.rect.top;
+                        // Map the top edge of next task view into the local space of the current
+                        // task view to find the clip amount in local space
+                        mTmpCoord[0] = mTmpCoord[1] = 0;
+                        Utilities.mapCoordInDescendentToSelf(nextTv, this, mTmpCoord, false);
+                        Utilities.mapCoordInSelfToDescendent(tv, this, mTmpCoord, mTmpMatrix);
+                        clipBottom = (int) Math.floor(tv.getMeasuredHeight() - mTmpCoord[1]
+                                - nextTv.getPaddingTop() - 1);
                     }
                 }
                 tv.getViewBounds().setClipBottom(clipBottom);
@@ -363,6 +389,7 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
                 tv.getViewBounds().setClipBottom(0);
             }
         }
+        mStackViewsClipDirty = false;
     }
 
     /** The stack insets to apply to the stack contents */
@@ -665,6 +692,7 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
                 ctx.currentTaskRect = mLayoutAlgorithm.mTaskRect;
                 ctx.currentTaskOccludesLaunchTarget = (launchTargetTask != null) &&
                         launchTargetTask.group.isTaskAboveTask(task, launchTargetTask);
+                ctx.updateListener = mRequestUpdateClippingListener;
                 mLayoutAlgorithm.getStackTransform(task, mStackScroller.getStackScroll(), ctx.currentTaskTransform, null);
                 tv.startEnterRecentsAnimation(ctx);
             }
@@ -1003,7 +1031,9 @@ public class TaskStackView extends FrameLayout implements TaskStack.TaskStackCal
 
     @Override
     public void onTaskViewClipStateChanged(TaskView tv) {
-        invalidate();
+        if (!mStackViewsDirty) {
+            invalidate();
+        }
     }
 
     @Override
diff --git a/packages/SystemUI/src/com/android/systemui/recents/views/TaskView.java b/packages/SystemUI/src/com/android/systemui/recents/views/TaskView.java
index 4baf31f..1750804 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/views/TaskView.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/TaskView.java
@@ -20,12 +20,7 @@ import android.animation.Animator;
 import android.animation.ObjectAnimator;
 import android.animation.ValueAnimator;
 import android.content.Context;
-import android.graphics.Color;
-import android.graphics.Outline;
-import android.graphics.Paint;
-import android.graphics.PorterDuff;
-import android.graphics.PorterDuffColorFilter;
-import android.graphics.Rect;
+import android.graphics.*;
 import android.graphics.drawable.Drawable;
 import android.graphics.drawable.LayerDrawable;
 import android.util.AttributeSet;
@@ -74,6 +69,7 @@ public class TaskView extends FrameLayout implements Task.TaskCallbacks,
     AnimateableViewBounds mViewBounds;
     Paint mLayerPaint = new Paint();
 
+    View mContent;
     TaskViewThumbnail mThumbnailView;
     TaskViewHeader mHeaderView;
     TaskViewFooter mFooterView;
@@ -134,15 +130,16 @@ public class TaskView extends FrameLayout implements Task.TaskCallbacks,
     @Override
     protected void onFinishInflate() {
         // Bind the views
+        mContent = findViewById(R.id.task_view_content);
         mHeaderView = (TaskViewHeader) findViewById(R.id.task_view_bar);
         mThumbnailView = (TaskViewThumbnail) findViewById(R.id.task_view_thumbnail);
+        mThumbnailView.enableTaskBarClip(mHeaderView);
         mActionButtonView = findViewById(R.id.lock_to_app_fab);
         mActionButtonView.setOutlineProvider(new ViewOutlineProvider() {
             @Override
             public void getOutline(View view, Outline outline) {
                 // Set the outline to match the FAB background
-                outline.setOval(0, 0, mActionButtonView.getWidth(),
-                        mActionButtonView.getHeight());
+                outline.setOval(0, 0, mActionButtonView.getWidth(), mActionButtonView.getHeight());
             }
         });
         if (mFooterView != null) {
@@ -157,6 +154,11 @@ public class TaskView extends FrameLayout implements Task.TaskCallbacks,
 
         int widthWithoutPadding = width - mPaddingLeft - mPaddingRight;
         int heightWithoutPadding = height - mPaddingTop - mPaddingBottom;
+
+        // Measure the content
+        mContent.measure(MeasureSpec.makeMeasureSpec(widthWithoutPadding, MeasureSpec.EXACTLY),
+                MeasureSpec.makeMeasureSpec(widthWithoutPadding, MeasureSpec.EXACTLY));
+
         // Measure the bar view, thumbnail, and footer
         mHeaderView.measure(MeasureSpec.makeMeasureSpec(widthWithoutPadding, MeasureSpec.EXACTLY),
                 MeasureSpec.makeMeasureSpec(mConfig.taskBarHeight, MeasureSpec.EXACTLY));
@@ -186,6 +188,11 @@ public class TaskView extends FrameLayout implements Task.TaskCallbacks,
 
     /** Synchronizes this view's properties with the task's transform */
     void updateViewPropertiesToTaskTransform(TaskViewTransform toTransform, int duration) {
+        updateViewPropertiesToTaskTransform(toTransform, duration, null);
+    }
+
+    void updateViewPropertiesToTaskTransform(TaskViewTransform toTransform, int duration,
+                                             ValueAnimator.AnimatorUpdateListener updateCallback) {
         // If we are a full screen view, then only update the Z to keep it in order
         // XXX: Also update/animate the dim as well
         if (mIsFullScreenView) {
@@ -198,7 +205,7 @@ public class TaskView extends FrameLayout implements Task.TaskCallbacks,
 
         // Apply the transform
         toTransform.applyToTaskView(this, duration, mConfig.fastOutSlowInInterpolator, false,
-                !mConfig.fakeShadows);
+                !mConfig.fakeShadows, updateCallback);
 
         // Update the task progress
         if (mTaskProgressAnimator != null) {
@@ -331,8 +338,6 @@ public class TaskView extends FrameLayout implements Task.TaskCallbacks,
                                 mViewBounds.setClipRight(0);
                                 // Reset the bar translation
                                 mHeaderView.setTranslationY(0);
-                                // Enable the thumbnail clip
-                                mThumbnailView.enableTaskBarClip(mHeaderView);
                                 // Animate the footer into view (if it is the front most task)
                                 animateFooterVisibility(true, mConfig.taskBarEnterAnimDuration);
 
@@ -349,9 +354,6 @@ public class TaskView extends FrameLayout implements Task.TaskCallbacks,
                         })
                         .start();
             } else {
-                // Otherwise, just enable the thumbnail clip
-                mThumbnailView.enableTaskBarClip(mHeaderView);
-
                 // Animate the footer into view
                 animateFooterVisibility(true, 0);
             }
@@ -359,8 +361,6 @@ public class TaskView extends FrameLayout implements Task.TaskCallbacks,
 
         } else if (mConfig.launchedFromAppWithThumbnail) {
             if (mTask.isLaunchTarget) {
-                // Enable the task bar clip
-                mThumbnailView.enableTaskBarClip(mHeaderView);
                 // Animate the dim/overlay
                 if (Constants.DebugFlags.App.EnableThumbnailAlphaOnFrontmost) {
                     // Animate the thumbnail alpha before the dim animation (to prevent updating the
@@ -392,8 +392,6 @@ public class TaskView extends FrameLayout implements Task.TaskCallbacks,
                         .withLayer()
                         .start();
             } else {
-                // Enable the task bar clip
-                mThumbnailView.enableTaskBarClip(mHeaderView);
                 // Animate the task up if it was occluding the launch target
                 if (ctx.currentTaskOccludesLaunchTarget) {
                     setTranslationY(transform.translationY + mConfig.taskViewAffiliateGroupEnterOffsetPx);
@@ -407,7 +405,6 @@ public class TaskView extends FrameLayout implements Task.TaskCallbacks,
                             .withEndAction(new Runnable() {
                                 @Override
                                 public void run() {
-                                    mThumbnailView.enableTaskBarClip(mHeaderView);
                                     // Decrement the post animation trigger
                                     ctx.postAnimationTrigger.decrement();
                                 }
@@ -421,8 +418,11 @@ public class TaskView extends FrameLayout implements Task.TaskCallbacks,
         } else if (mConfig.launchedFromHome) {
             // Animate the tasks up
             int frontIndex = (ctx.currentStackViewCount - ctx.currentStackViewIndex - 1);
-            int delay = mConfig.taskViewEnterFromHomeDelay +
-                    frontIndex * mConfig.taskViewEnterFromHomeStaggerDelay;
+            float fraction = (float) frontIndex / (ctx.currentStackViewCount - 1);
+            fraction = (float) Math.pow(fraction, 0.85f);
+            int delay = (int) (mConfig.taskViewEnterFromHomeDelay +
+                                fraction * mConfig.taskViewEnterFromHomeStaggerDelay);
+            long delayIncrease = (long) (fraction * mConfig.taskViewEnterFromHomeStaggerDuration);
             if (!mConfig.fakeShadows) {
                 animate().translationZ(transform.translationZ);
             }
@@ -431,13 +431,12 @@ public class TaskView extends FrameLayout implements Task.TaskCallbacks,
                     .scaleY(transform.scale)
                     .translationY(transform.translationY)
                     .setStartDelay(delay)
-                    .setUpdateListener(null)
+                    .setUpdateListener(ctx.updateListener)
                     .setInterpolator(mConfig.quintOutInterpolator)
-                    .setDuration(mConfig.taskViewEnterFromHomeDuration)
+                    .setDuration(mConfig.taskViewEnterFromHomeDuration + delayIncrease)
                     .withEndAction(new Runnable() {
                         @Override
                         public void run() {
-                            mThumbnailView.enableTaskBarClip(mHeaderView);
                             // Decrement the post animation trigger
                             ctx.postAnimationTrigger.decrement();
                         }
@@ -450,9 +449,6 @@ public class TaskView extends FrameLayout implements Task.TaskCallbacks,
             startDelay = delay;
 
         } else {
-            // Otherwise, just enable the thumbnail clip
-            mThumbnailView.enableTaskBarClip(mHeaderView);
-
             // Animate the footer into view
             animateFooterVisibility(true, 0);
         }
@@ -484,8 +480,6 @@ public class TaskView extends FrameLayout implements Task.TaskCallbacks,
     void startLaunchTaskAnimation(final Runnable postAnimRunnable, boolean isLaunchingTask,
             boolean occludesLaunchTarget, boolean lockToTask) {
         if (isLaunchingTask) {
-            // Disable the thumbnail clip
-            mThumbnailView.disableTaskBarClip();
             // Animate the thumbnail alpha back into full opacity for the window animation out
             mThumbnailView.startLaunchTaskAnimation(postAnimRunnable);
 
@@ -662,7 +656,7 @@ public class TaskView extends FrameLayout implements Task.TaskCallbacks,
                 int inverse = 255 - mDim;
                 mDimColorFilter.setColor(Color.argb(0xFF, inverse, inverse, inverse));
                 mLayerPaint.setColorFilter(mDimColorFilter);
-                setLayerType(LAYER_TYPE_HARDWARE, mLayerPaint);
+                mContent.setLayerType(LAYER_TYPE_HARDWARE, mLayerPaint);
             }
         } else {
             float dimAlpha = mDim / 255.0f;
diff --git a/packages/SystemUI/src/com/android/systemui/recents/views/TaskViewHeader.java b/packages/SystemUI/src/com/android/systemui/recents/views/TaskViewHeader.java
index fd39126..396d441 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/views/TaskViewHeader.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/TaskViewHeader.java
@@ -259,6 +259,14 @@ public class TaskViewHeader extends FrameLayout {
         }
     }
 
+    @Override
+    protected int[] onCreateDrawableState(int extraSpace) {
+
+        // Don't forward our state to the drawable - we do it manually in onTaskViewFocusChanged.
+        // This is to prevent layer trashing when the view is pressed.
+        return new int[] {};
+    }
+
     /** Notifies the associated TaskView has been focused. */
     void onTaskViewFocusChanged(boolean focused) {
         boolean isRunning = false;
diff --git a/packages/SystemUI/src/com/android/systemui/recents/views/TaskViewThumbnail.java b/packages/SystemUI/src/com/android/systemui/recents/views/TaskViewThumbnail.java
index 11ca103..a946a84 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/views/TaskViewThumbnail.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/TaskViewThumbnail.java
@@ -52,6 +52,8 @@ public class TaskViewThumbnail extends View {
     private BitmapShader mBitmapShader;
     private float mBitmapAlpha;
     private float mDimAlpha;
+    private View mTaskBar;
+    private boolean mInvisible;
     private ValueAnimator mAlphaAnimator;
     private ValueAnimator.AnimatorUpdateListener mAlphaUpdateListener
             = new ValueAnimator.AnimatorUpdateListener() {
@@ -85,6 +87,9 @@ public class TaskViewThumbnail extends View {
 
     @Override
     protected void onDraw(Canvas canvas) {
+        if (mInvisible) {
+            return;
+        }
         canvas.drawRoundRect(0,
                 0,
                 getWidth(),
@@ -101,6 +106,9 @@ public class TaskViewThumbnail extends View {
     }
 
     private void updateFilter() {
+        if (mInvisible) {
+            return;
+        }
         int mul = (int) ((1.0f - mDimAlpha) * mBitmapAlpha * 255);
         int add = (int) ((1.0f - mDimAlpha) * (1 - mBitmapAlpha) * 255);
         if (mBitmapShader != null) {
@@ -118,16 +126,22 @@ public class TaskViewThumbnail extends View {
 
     /** Updates the clip rect based on the given task bar. */
     void enableTaskBarClip(View taskBar) {
+        mTaskBar = taskBar;
         int top = (int) Math.max(0, taskBar.getTranslationY() +
                 taskBar.getMeasuredHeight() - 1);
         mClipRect.set(0, top, getMeasuredWidth(), getMeasuredHeight());
         setClipBounds(mClipRect);
     }
 
-    /** Disables the task bar clipping. */
-    void disableTaskBarClip() {
-        mClipRect.set(0, 0, getMeasuredWidth(), getMeasuredHeight());
-        setClipBounds(mClipRect);
+    void updateVisibility(int clipBottom) {
+        boolean invisible = mTaskBar != null && getHeight() - clipBottom < mTaskBar.getHeight();
+        if (invisible != mInvisible) {
+            mInvisible = invisible;
+            if (!mInvisible) {
+                updateFilter();
+            }
+            invalidate();
+        }
     }
 
     /** Binds the thumbnail view to the screenshot. */
diff --git a/packages/SystemUI/src/com/android/systemui/recents/views/TaskViewTransform.java b/packages/SystemUI/src/com/android/systemui/recents/views/TaskViewTransform.java
index fee4e80..42c0f9f 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/views/TaskViewTransform.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/TaskViewTransform.java
@@ -78,7 +78,7 @@ public class TaskViewTransform {
 
     /** Applies this transform to a view. */
     public void applyToTaskView(View v, int duration, Interpolator interp, boolean allowLayers,
-            boolean allowShadows) {
+            boolean allowShadows, ValueAnimator.AnimatorUpdateListener updateCallback) {
         // Check to see if any properties have changed, and update the task view
         if (duration > 0) {
             ViewPropertyAnimator anim = v.animate();
@@ -104,6 +104,11 @@ public class TaskViewTransform {
             if (requiresLayers && allowLayers) {
                 anim.withLayer();
             }
+            if (updateCallback != null) {
+                anim.setUpdateListener(updateCallback);
+            } else {
+                anim.setUpdateListener(null);
+            }
             anim.setStartDelay(startDelay)
                     .setDuration(duration)
                     .setInterpolator(interp)
diff --git a/packages/SystemUI/src/com/android/systemui/recents/views/ViewAnimation.java b/packages/SystemUI/src/com/android/systemui/recents/views/ViewAnimation.java
index a1fc40f..4586f12 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/views/ViewAnimation.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/views/ViewAnimation.java
@@ -16,6 +16,7 @@
 
 package com.android.systemui.recents.views;
 
+import android.animation.ValueAnimator;
 import android.graphics.Rect;
 import com.android.systemui.recents.misc.ReferenceCountedTrigger;
 
@@ -27,6 +28,8 @@ public class ViewAnimation {
         // A trigger to run some logic when all the animations complete.  This works around the fact
         // that it is difficult to coordinate ViewPropertyAnimators
         ReferenceCountedTrigger postAnimationTrigger;
+        // An update listener to notify as the enter animation progresses (used for the home transition)
+        ValueAnimator.AnimatorUpdateListener updateListener;
 
         // These following properties are updated for each task view we start the enter animation on