Fading the edges of the thumbnail if the size is different than the view size

Change-Id: I7bfb9d55ccbf4fa0338bc962632cfeac37cd69be
diff --git a/quickstep/res/drawable/task_thumbnail_background.xml b/quickstep/res/drawable/task_thumbnail_background.xml
deleted file mode 100644
index f1f48ac..0000000
--- a/quickstep/res/drawable/task_thumbnail_background.xml
+++ /dev/null
@@ -1,18 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!-- Copyright (C) 2017 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.
--->
-<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
-    <corners android:radius="2dp" />
-</shape>
diff --git a/quickstep/res/layout/task.xml b/quickstep/res/layout/task.xml
index 839d934..91b6aa3 100644
--- a/quickstep/res/layout/task.xml
+++ b/quickstep/res/layout/task.xml
@@ -1,5 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!--
+<?xml version="1.0" encoding="utf-8"?><!--
      Copyright (C) 2017 The Android Open Source Project
 
      Licensed under the Apache License, Version 2.0 (the "License");
@@ -14,23 +13,20 @@
      See the License for the specific language governing permissions and
      limitations under the License.
 -->
-<com.android.quickstep.TaskView
-    xmlns:android="http://schemas.android.com/apk/res/android"
+<com.android.quickstep.TaskView xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
-    android:layout_height="match_parent">
+    android:layout_height="match_parent"
+    android:elevation="4dp">
 
     <com.android.quickstep.TaskThumbnailView
         android:id="@+id/snapshot"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
-        android:layout_marginTop="@dimen/task_thumbnail_top_margin"
-        android:scaleType="matrix"
-        android:background="@drawable/task_thumbnail_background"
-        android:elevation="4dp" />
+        android:layout_marginTop="@dimen/task_thumbnail_top_margin" />
+
     <ImageView
         android:id="@+id/icon"
         android:layout_width="@dimen/task_thumbnail_icon_size"
         android:layout_height="@dimen/task_thumbnail_icon_size"
-        android:layout_gravity="top|center_horizontal"
-        android:elevation="5dp"/>
+        android:layout_gravity="top|center_horizontal" />
 </com.android.quickstep.TaskView>
\ No newline at end of file
diff --git a/quickstep/res/values/dimens.xml b/quickstep/res/values/dimens.xml
index 222a3f4..076f0a3 100644
--- a/quickstep/res/values/dimens.xml
+++ b/quickstep/res/values/dimens.xml
@@ -19,6 +19,9 @@
     <dimen name="task_thumbnail_top_margin">24dp</dimen>
     <dimen name="task_thumbnail_icon_size">48dp</dimen>
     <dimen name="task_menu_background_radius">12dp</dimen>
+    <dimen name="task_corner_radius">2dp</dimen>
+    <dimen name="task_fade_length">20dp</dimen>
+
 
     <dimen name="quickstep_fling_threshold_velocity">500dp</dimen>
     <dimen name="quickstep_fling_min_velocity">250dp</dimen>
diff --git a/quickstep/src/com/android/quickstep/RecentsView.java b/quickstep/src/com/android/quickstep/RecentsView.java
index 9c757bf..605c83c 100644
--- a/quickstep/src/com/android/quickstep/RecentsView.java
+++ b/quickstep/src/com/android/quickstep/RecentsView.java
@@ -72,7 +72,7 @@
             for (int i = mFirstTaskIndex; i < getChildCount(); i++) {
                 final TaskView taskView = (TaskView) getChildAt(i);
                 if (taskView.getTask().key.id == taskId) {
-                    taskView.getThumbnail().setThumbnail(snapshot);
+                    taskView.getThumbnail().setThumbnail(taskView.getTask(), snapshot);
                     return;
                 }
             }
diff --git a/quickstep/src/com/android/quickstep/TaskThumbnailView.java b/quickstep/src/com/android/quickstep/TaskThumbnailView.java
index 473681f..87dec67 100644
--- a/quickstep/src/com/android/quickstep/TaskThumbnailView.java
+++ b/quickstep/src/com/android/quickstep/TaskThumbnailView.java
@@ -22,35 +22,43 @@
 import android.graphics.BitmapShader;
 import android.graphics.Canvas;
 import android.graphics.Color;
+import android.graphics.ComposeShader;
 import android.graphics.LightingColorFilter;
+import android.graphics.LinearGradient;
 import android.graphics.Matrix;
 import android.graphics.Paint;
+import android.graphics.PorterDuff.Mode;
 import android.graphics.Rect;
 import android.graphics.Shader;
 import android.util.AttributeSet;
-import android.widget.FrameLayout;
+import android.view.View;
 
 import com.android.launcher3.DeviceProfile;
 import com.android.launcher3.Launcher;
+import com.android.launcher3.R;
+import com.android.systemui.shared.recents.model.Task;
 import com.android.systemui.shared.recents.model.ThumbnailData;
 
 /**
  * A task in the Recents view.
  */
-public class TaskThumbnailView extends FrameLayout {
+public class TaskThumbnailView extends View {
+
+    private static final LightingColorFilter[] sDimFilterCache = new LightingColorFilter[256];
+
+    private final float mCornerRadius;
+    private final float mFadeLength;
+
+    private final Paint mPaint = new Paint();
+
+    private final Matrix mMatrix = new Matrix();
+    private final Rect mThumbnailRect = new Rect();
 
     private ThumbnailData mThumbnailData;
-
-    private Rect mThumbnailRect = new Rect();
-    private float mThumbnailScale;
-
-    private Matrix mMatrix = new Matrix();
-    private Paint mDrawPaint = new Paint();
-    protected Paint mBgFillPaint = new Paint();
     protected BitmapShader mBitmapShader;
 
+    private float mThumbnailScale;
     private float mDimAlpha = 1f;
-    private LightingColorFilter mLightingColorFilter = new LightingColorFilter(Color.WHITE, 0);
 
     public TaskThumbnailView(Context context) {
         this(context, null);
@@ -62,32 +70,34 @@
 
     public TaskThumbnailView(Context context, AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
-        setWillNotDraw(false);
-        setClipToOutline(true);
+        mCornerRadius = getResources().getDimension(R.dimen.task_corner_radius);
+        mFadeLength = getResources().getDimension(R.dimen.task_fade_length);
     }
 
     /**
      * Updates this thumbnail.
      */
-    public void setThumbnail(ThumbnailData thumbnailData) {
+    public void setThumbnail(Task task, ThumbnailData thumbnailData) {
+        mPaint.setColor(task == null ? Color.BLACK : task.colorBackground | 0xFF000000);
+
         if (thumbnailData != null && thumbnailData.thumbnail != null) {
             Bitmap bm = thumbnailData.thumbnail;
             bm.prepareToDraw();
             mThumbnailScale = thumbnailData.scale;
             mBitmapShader = new BitmapShader(bm, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
-            mDrawPaint.setShader(mBitmapShader);
+            mPaint.setShader(mBitmapShader);
             mThumbnailRect.set(0, 0,
                     bm.getWidth() - thumbnailData.insets.left - thumbnailData.insets.right,
                     bm.getHeight() - thumbnailData.insets.top - thumbnailData.insets.bottom);
             mThumbnailData = thumbnailData;
             updateThumbnailMatrix();
-            updateThumbnailPaintFilter();
         } else {
             mBitmapShader = null;
-            mDrawPaint.setShader(null);
-            mThumbnailRect.setEmpty();
             mThumbnailData = null;
+            mPaint.setShader(null);
+            mThumbnailRect.setEmpty();
         }
+        updateThumbnailPaintFilter();
     }
 
     /**
@@ -100,43 +110,17 @@
 
     @Override
     protected void onDraw(Canvas canvas) {
-        int viewWidth = getMeasuredWidth();
-        int viewHeight = getMeasuredHeight();
-        int thumbnailWidth = Math.min(viewWidth,
-                (int) (mThumbnailRect.width() * mThumbnailScale));
-        int thumbnailHeight = Math.min(viewHeight,
-                (int) (mThumbnailRect.height() * mThumbnailScale));
-
-        if (mBitmapShader != null && thumbnailWidth > 0 && thumbnailHeight > 0) {
-            // Draw the background, there will be some small overdraw with the thumbnail
-            if (thumbnailWidth < viewWidth) {
-                // Portrait thumbnail on a landscape task view
-                canvas.drawRect(Math.max(0, thumbnailWidth), 0, viewWidth, viewHeight,
-                        mBgFillPaint);
-            }
-            if (thumbnailHeight < viewHeight) {
-                // Landscape thumbnail on a portrait task view
-                canvas.drawRect(0, Math.max(0, thumbnailHeight), viewWidth, viewHeight,
-                        mBgFillPaint);
-            }
-
-            // Draw the thumbnail
-            canvas.drawRect(0, 0, thumbnailWidth, thumbnailHeight, mDrawPaint);
-        } else {
-            canvas.drawRect(0, 0, viewWidth, viewHeight, mBgFillPaint);
-        }
+        canvas.drawRoundRect(0, 0, getMeasuredWidth(), getMeasuredHeight(),
+                mCornerRadius, mCornerRadius, mPaint);
     }
 
     private void updateThumbnailPaintFilter() {
         int mul = (int) (mDimAlpha * 255);
         if (mBitmapShader != null) {
-            mLightingColorFilter = new LightingColorFilter(Color.argb(255, mul, mul, mul), 0);
-            mDrawPaint.setColorFilter(mLightingColorFilter);
-            mDrawPaint.setColor(0xFFffffff);
-            mBgFillPaint.setColorFilter(mLightingColorFilter);
+            mPaint.setColorFilter(getLightingColorFilter(mul));
         } else {
-            mDrawPaint.setColorFilter(null);
-            mDrawPaint.setColor(Color.argb(255, mul, mul, mul));
+            mPaint.setColorFilter(null);
+            mPaint.setColor(Color.argb(255, mul, mul, mul));
         }
         invalidate();
     }
@@ -170,6 +154,26 @@
             mMatrix.setTranslate(-mThumbnailData.insets.left, -mThumbnailData.insets.top);
             mMatrix.postScale(mThumbnailScale, mThumbnailScale);
             mBitmapShader.setLocalMatrix(mMatrix);
+
+            float bitmapHeight = Math.max(mThumbnailRect.height() * mThumbnailScale, 0);
+            Shader shader = mBitmapShader;
+            if (bitmapHeight < getMeasuredHeight()) {
+                int color = mPaint.getColor();
+                LinearGradient fade = new LinearGradient(
+                        0, bitmapHeight - mFadeLength, 0, bitmapHeight,
+                        color & 0x00FFFFFF, color, Shader.TileMode.CLAMP);
+                shader = new ComposeShader(fade, shader, Mode.DST_OVER);
+            }
+
+            float bitmapWidth = Math.max(mThumbnailRect.width() * mThumbnailScale, 0);
+            if (bitmapWidth < getMeasuredWidth()) {
+                int color = mPaint.getColor();
+                LinearGradient fade = new LinearGradient(
+                        bitmapWidth - mFadeLength, 0, bitmapWidth, 0,
+                        color & 0x00FFFFFF, color, Shader.TileMode.CLAMP);
+                shader = new ComposeShader(fade, shader, Mode.DST_OVER);
+            }
+            mPaint.setShader(shader);
         }
         invalidate();
     }
@@ -179,4 +183,17 @@
         super.onSizeChanged(w, h, oldw, oldh);
         updateThumbnailMatrix();
     }
+
+    private static LightingColorFilter getLightingColorFilter(int dimColor) {
+        if (dimColor < 0) {
+            dimColor = 0;
+        } else if (dimColor > 255) {
+            dimColor = 255;
+        }
+        if (sDimFilterCache[dimColor] == null) {
+            sDimFilterCache[dimColor] =
+                    new LightingColorFilter(Color.argb(255, dimColor, dimColor, dimColor), 0);
+        }
+        return sDimFilterCache[dimColor];
+    }
 }
diff --git a/quickstep/src/com/android/quickstep/TaskView.java b/quickstep/src/com/android/quickstep/TaskView.java
index 5c15a76..0e999f8 100644
--- a/quickstep/src/com/android/quickstep/TaskView.java
+++ b/quickstep/src/com/android/quickstep/TaskView.java
@@ -16,13 +16,20 @@
 
 package com.android.quickstep;
 
+import static com.android.quickstep.RecentsView.SCROLL_TYPE_TASK;
+import static com.android.quickstep.RecentsView.SCROLL_TYPE_WORKSPACE;
+
 import android.animation.ObjectAnimator;
 import android.animation.TimeInterpolator;
 import android.app.ActivityOptions;
 import android.content.Context;
+import android.content.res.Resources;
+import android.graphics.Outline;
 import android.graphics.Rect;
 import android.util.AttributeSet;
 import android.util.Property;
+import android.view.View;
+import android.view.ViewOutlineProvider;
 import android.widget.FrameLayout;
 import android.widget.ImageView;
 
@@ -40,9 +47,6 @@
 import java.util.ArrayList;
 import java.util.List;
 
-import static com.android.quickstep.RecentsView.SCROLL_TYPE_TASK;
-import static com.android.quickstep.RecentsView.SCROLL_TYPE_WORKSPACE;
-
 /**
  * A task in the Recents view.
  */
@@ -90,9 +94,8 @@
 
     public TaskView(Context context, AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
-        setOnClickListener((view) -> {
-            launchTask(true /* animate */);
-        });
+        setOnClickListener((view) -> launchTask(true /* animate */));
+        setOutlineProvider(new TaskOutlineProvider(getResources()));
     }
 
     @Override
@@ -155,14 +158,14 @@
 
     @Override
     public void onTaskDataLoaded(Task task, ThumbnailData thumbnailData) {
-        mSnapshotView.setThumbnail(thumbnailData);
+        mSnapshotView.setThumbnail(task, thumbnailData);
         mIconView.setImageDrawable(task.icon);
         mIconView.setOnLongClickListener(icon -> TaskMenuView.showForTask(this));
     }
 
     @Override
     public void onTaskDataUnloaded() {
-        mSnapshotView.setThumbnail(null);
+        mSnapshotView.setThumbnail(null, null);
         mIconView.setImageDrawable(null);
         mIconView.setOnLongClickListener(null);
     }
@@ -216,4 +219,22 @@
         scrollState.prevPageExtraWidth = 0;
         return SCROLL_TYPE_TASK;
     }
+
+
+    private static final class TaskOutlineProvider extends ViewOutlineProvider {
+
+        private final int mMarginTop;
+        private final float mRadius;
+
+        TaskOutlineProvider(Resources res) {
+            mMarginTop = res.getDimensionPixelSize(R.dimen.task_thumbnail_top_margin);
+            mRadius = res.getDimension(R.dimen.task_corner_radius);
+        }
+
+        @Override
+        public void getOutline(View view, Outline outline) {
+            outline.setRoundRect(0, mMarginTop, view.getWidth(),
+                    view.getHeight(), mRadius);
+        }
+    }
 }