Optimizing shadow generation by reusing bitmap.

> Not creating unnecessary bitmaps
> Final bitmap is generated as ALPHA_8 instead of ARGB_8888
> The shadow drawing is done directly in the view

Change-Id: I504fa2ea3abdc1a3c3fb9ad57d6e28880d2584a1

5 files changed, 183 insertions, 156 deletions

diff --git a/src/com/android/launcher3/BubbleTextView.java b/src/com/android/launcher3/BubbleTextView.java
index bbcd893f2..5dc3b1239 100644
--- a/src/com/android/launcher3/BubbleTextView.java
+++ b/src/com/android/launcher3/BubbleTextView.java
@@ -276,7 +276,7 @@ public class BubbleTextView extends TextView {
         // Only show the shadow effect when persistent pressed state is set.
         if (getParent() instanceof ShortcutAndWidgetContainer) {
             CellLayout layout = (CellLayout) getParent().getParent();
-            layout.setPressedIcon(this, mPressedBackground, mOutlineHelper.shadowBitmapPadding);
+            layout.setPressedIcon(this, mPressedBackground);
         }
 
         updateIconState();
diff --git a/src/com/android/launcher3/CellLayout.java b/src/com/android/launcher3/CellLayout.java
index 72eabf177..a348008d8 100644
--- a/src/com/android/launcher3/CellLayout.java
+++ b/src/com/android/launcher3/CellLayout.java
@@ -132,7 +132,7 @@ public class CellLayout extends ViewGroup {
     private int mDragOutlineCurrent = 0;
     private final Paint mDragOutlinePaint = new Paint();
 
-    private final FastBitmapView mTouchFeedbackView;
+    private final ClickShadowView mTouchFeedbackView;
 
     @Thunk HashMap<CellLayout.LayoutParams, Animator> mReorderAnimators = new
             HashMap<CellLayout.LayoutParams, Animator>();
@@ -301,9 +301,8 @@ public class CellLayout extends ViewGroup {
         mShortcutsAndWidgets.setCellDimensions(mCellWidth, mCellHeight, mWidthGap, mHeightGap,
                 mCountX, mCountY);
 
-        mTouchFeedbackView = new FastBitmapView(context);
-        // Make the feedback view large enough to hold the blur bitmap.
-        addView(mTouchFeedbackView, (int) (grid.cellWidthPx * 1.5), (int) (grid.cellHeightPx * 1.5));
+        mTouchFeedbackView = new ClickShadowView(context);
+        addView(mTouchFeedbackView);
         addView(mShortcutsAndWidgets);
     }
 
@@ -410,22 +409,14 @@ public class CellLayout extends ViewGroup {
         invalidate();
     }
 
-    void setPressedIcon(BubbleTextView icon, Bitmap background, int padding) {
+    void setPressedIcon(BubbleTextView icon, Bitmap background) {
         if (icon == null || background == null) {
             mTouchFeedbackView.setBitmap(null);
             mTouchFeedbackView.animate().cancel();
         } else {
-            int offset = getMeasuredWidth() - getPaddingLeft() - getPaddingRight()
-                    - (mCountX * mCellWidth);
-            mTouchFeedbackView.setTranslationX(icon.getLeft() + (int) Math.ceil(offset / 2f)
-                    - padding);
-            mTouchFeedbackView.setTranslationY(icon.getTop() - padding);
             if (mTouchFeedbackView.setBitmap(background)) {
-                mTouchFeedbackView.setAlpha(0);
-                mTouchFeedbackView.animate().alpha(1)
-                    .setDuration(FastBitmapDrawable.CLICK_FEEDBACK_DURATION)
-                    .setInterpolator(FastBitmapDrawable.CLICK_FEEDBACK_INTERPOLATOR)
-                    .start();
+                mTouchFeedbackView.alignWithIconView(icon, mShortcutsAndWidgets);
+                mTouchFeedbackView.animateShadow();
             }
         }
     }
@@ -895,19 +886,20 @@ public class CellLayout extends ViewGroup {
             mWidthGap = mOriginalWidthGap;
             mHeightGap = mOriginalHeightGap;
         }
-        int count = getChildCount();
-        int maxWidth = 0;
-        int maxHeight = 0;
-        for (int i = 0; i < count; i++) {
-            View child = getChildAt(i);
-            int childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(newWidth,
-                    MeasureSpec.EXACTLY);
-            int childheightMeasureSpec = MeasureSpec.makeMeasureSpec(newHeight,
-                    MeasureSpec.EXACTLY);
-            child.measure(childWidthMeasureSpec, childheightMeasureSpec);
-            maxWidth = Math.max(maxWidth, child.getMeasuredWidth());
-            maxHeight = Math.max(maxHeight, child.getMeasuredHeight());
-        }
+
+        // Make the feedback view large enough to hold the blur bitmap.
+        mTouchFeedbackView.measure(
+                MeasureSpec.makeMeasureSpec(mCellWidth + mTouchFeedbackView.getExtraSize(),
+                        MeasureSpec.EXACTLY),
+                MeasureSpec.makeMeasureSpec(mCellHeight + mTouchFeedbackView.getExtraSize(),
+                        MeasureSpec.EXACTLY));
+
+        mShortcutsAndWidgets.measure(
+                MeasureSpec.makeMeasureSpec(newWidth, MeasureSpec.EXACTLY),
+                MeasureSpec.makeMeasureSpec(newHeight, MeasureSpec.EXACTLY));
+
+        int maxWidth = mShortcutsAndWidgets.getMeasuredWidth();
+        int maxHeight = mShortcutsAndWidgets.getMeasuredHeight();
         if (mFixedWidth > 0 && mFixedHeight > 0) {
             setMeasuredDimension(maxWidth, maxHeight);
         } else {
@@ -921,13 +913,13 @@ public class CellLayout extends ViewGroup {
                 (mCountX * mCellWidth);
         int left = getPaddingLeft() + (int) Math.ceil(offset / 2f);
         int top = getPaddingTop();
-        int count = getChildCount();
-        for (int i = 0; i < count; i++) {
-            View child = getChildAt(i);
-            child.layout(left, top,
-                    left + r - l,
-                    top + b - t);
-        }
+
+        mTouchFeedbackView.layout(left, top,
+                left + mTouchFeedbackView.getMeasuredWidth(),
+                top + mTouchFeedbackView.getMeasuredHeight());
+        mShortcutsAndWidgets.layout(left, top,
+                left + r - l,
+                top + b - t);
     }
 
     @Override
diff --git a/src/com/android/launcher3/ClickShadowView.java b/src/com/android/launcher3/ClickShadowView.java
new file mode 100644
index 000000000..42fafe275
--- /dev/null
+++ b/src/com/android/launcher3/ClickShadowView.java
@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2014 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.launcher3;
+
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
+import android.graphics.Color;
+import android.graphics.Paint;
+import android.view.View;
+import android.view.ViewGroup;
+
+public class ClickShadowView extends View {
+
+    private static final int SHADOW_SIZE_FACTOR = 3;
+    private static final int SHADOW_LOW_ALPHA = 30;
+    private static final int SHADOW_HIGH_ALPHA = 60;
+
+    private final Paint mPaint;
+
+    private final float mShadowOffset;
+    private final float mShadowPadding;
+
+    private Bitmap mBitmap;
+
+    public ClickShadowView(Context context) {
+        super(context);
+        mPaint = new Paint(Paint.FILTER_BITMAP_FLAG);
+        mPaint.setColor(Color.BLACK);
+
+        mShadowPadding = getResources().getDimension(R.dimen.blur_size_click_shadow);
+        mShadowOffset = getResources().getDimension(R.dimen.click_shadow_high_shift);
+    }
+
+    /**
+     * @return extra space required by the view to show the shadow.
+     */
+    public int getExtraSize() {
+        return (int) (SHADOW_SIZE_FACTOR * mShadowPadding);
+    }
+
+    /**
+     * Applies the new bitmap.
+     * @return true if the view was invalidated.
+     */
+    public boolean setBitmap(Bitmap b) {
+        if (b != mBitmap){
+            mBitmap = b;
+            invalidate();
+            return true;
+        }
+        return false;
+    }
+
+    @Override
+    protected void onDraw(Canvas canvas) {
+        if (mBitmap != null) {
+            mPaint.setAlpha(SHADOW_LOW_ALPHA);
+            canvas.drawBitmap(mBitmap, 0, 0, mPaint);
+            mPaint.setAlpha(SHADOW_HIGH_ALPHA);
+            canvas.drawBitmap(mBitmap, 0, mShadowOffset, mPaint);
+        }
+    }
+
+    public void animateShadow() {
+        setAlpha(0);
+        animate().alpha(1)
+            .setDuration(FastBitmapDrawable.CLICK_FEEDBACK_DURATION)
+            .setInterpolator(FastBitmapDrawable.CLICK_FEEDBACK_INTERPOLATOR)
+            .start();
+    }
+
+    /**
+     * Aligns the shadow with {@param view}
+     * @param viewParent immediate parent of {@param view}. It must be a sibling of this view.
+     */
+    public void alignWithIconView(BubbleTextView view, ViewGroup viewParent) {
+        float leftShift = view.getLeft() + viewParent.getLeft() - getLeft();
+        float topShift = view.getTop() + viewParent.getTop() - getTop();
+        int iconWidth = view.getRight() - view.getLeft();
+        int iconHSpace = iconWidth - view.getCompoundPaddingRight() - view.getCompoundPaddingLeft();
+        float drawableWidth = view.getIcon().getBounds().width();
+
+        setTranslationX(leftShift
+                + view.getCompoundPaddingLeft() * view.getScaleX()
+                + (iconHSpace - drawableWidth) * view.getScaleX() / 2  /* drawable gap */
+                + iconWidth * (1 - view.getScaleX()) / 2  /* gap due to scale */
+                - mShadowPadding  /* extra shadow size */
+                );
+        setTranslationY(topShift
+                + view.getPaddingTop() * view.getScaleY()  /* drawable gap */
+                + view.getHeight() * (1 - view.getScaleY()) / 2  /* gap due to scale */
+                - mShadowPadding  /* extra shadow size */
+                );
+    }
+}
diff --git a/src/com/android/launcher3/FastBitmapView.java b/src/com/android/launcher3/FastBitmapView.java
deleted file mode 100644
index 0937eb75e..000000000
--- a/src/com/android/launcher3/FastBitmapView.java
+++ /dev/null
@@ -1,58 +0,0 @@
-/*
- * Copyright (C) 2014 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.launcher3;
-
-import android.content.Context;
-import android.graphics.Bitmap;
-import android.graphics.Canvas;
-import android.graphics.Paint;
-import android.view.View;
-
-public class FastBitmapView extends View {
-
-    private final Paint mPaint = new Paint(Paint.FILTER_BITMAP_FLAG);
-    private Bitmap mBitmap;
-
-    public FastBitmapView(Context context) {
-        super(context);
-    }
-
-    /**
-     * Applies the new bitmap.
-     * @return true if the view was invalidated.
-     */
-    public boolean setBitmap(Bitmap b) {
-        if (b != mBitmap){
-            if (mBitmap != null) {
-                invalidate(0, 0, mBitmap.getWidth(), mBitmap.getHeight());
-            }
-            mBitmap = b;
-            if (mBitmap != null) {
-                invalidate(0, 0, mBitmap.getWidth(), mBitmap.getHeight());
-            }
-            return true;
-        }
-        return false;
-    }
-
-    @Override
-    protected void onDraw(Canvas canvas) {
-        if (mBitmap != null) {
-            canvas.drawBitmap(mBitmap, 0, 0, mPaint);
-        }
-    }
-}
diff --git a/src/com/android/launcher3/HolographicOutlineHelper.java b/src/com/android/launcher3/HolographicOutlineHelper.java
index b1e0e68a4..4a04d038a 100644
--- a/src/com/android/launcher3/HolographicOutlineHelper.java
+++ b/src/com/android/launcher3/HolographicOutlineHelper.java
@@ -17,6 +17,7 @@
 package com.android.launcher3;
 
 import android.content.Context;
+import android.content.res.Resources;
 import android.graphics.Bitmap;
 import android.graphics.BlurMaskFilter;
 import android.graphics.Canvas;
@@ -25,11 +26,16 @@ import android.graphics.Paint;
 import android.graphics.PorterDuff;
 import android.graphics.PorterDuffXfermode;
 import android.graphics.Rect;
-import android.graphics.Region.Op;
+import android.graphics.drawable.Drawable;
+import android.util.SparseArray;
 
+/**
+ * Utility class to generate shadow and outline effect, which are used for click feedback
+ * and drag-n-drop respectively.
+ */
 public class HolographicOutlineHelper {
 
-    private static final Rect sTempRect = new Rect();
+    private static HolographicOutlineHelper sInstance;
 
     private final Canvas mCanvas = new Canvas();
     private final Paint mDrawPaint = new Paint();
@@ -40,26 +46,23 @@ public class HolographicOutlineHelper {
     private final BlurMaskFilter mThinOuterBlurMaskFilter;
     private final BlurMaskFilter mMediumInnerBlurMaskFilter;
 
-    private final BlurMaskFilter mShaowBlurMaskFilter;
-    private final int mShadowOffset;
-
-    /**
-     * Padding used when creating shadow bitmap;
-     */
-    final int shadowBitmapPadding;
+    private final BlurMaskFilter mShadowBlurMaskFilter;
 
-    static HolographicOutlineHelper INSTANCE;
+    // We have 4 different icon sizes: homescreen, hotseat, folder & all-apps
+    private final SparseArray<Bitmap> mBitmapCache = new SparseArray<>(4);
 
     private HolographicOutlineHelper(Context context) {
-        final float scale = LauncherAppState.getInstance().getScreenDensity();
+        Resources res = context.getResources();
+
+        float mediumBlur = res.getDimension(R.dimen.blur_size_medium_outline);
+        mMediumOuterBlurMaskFilter = new BlurMaskFilter(mediumBlur, BlurMaskFilter.Blur.OUTER);
+        mMediumInnerBlurMaskFilter = new BlurMaskFilter(mediumBlur, BlurMaskFilter.Blur.NORMAL);
 
-        mMediumOuterBlurMaskFilter = new BlurMaskFilter(scale * 2.0f, BlurMaskFilter.Blur.OUTER);
-        mThinOuterBlurMaskFilter = new BlurMaskFilter(scale * 1.0f, BlurMaskFilter.Blur.OUTER);
-        mMediumInnerBlurMaskFilter = new BlurMaskFilter(scale * 2.0f, BlurMaskFilter.Blur.NORMAL);
+        mThinOuterBlurMaskFilter = new BlurMaskFilter(
+                res.getDimension(R.dimen.blur_size_thin_outline), BlurMaskFilter.Blur.OUTER);
 
-        mShaowBlurMaskFilter = new BlurMaskFilter(scale * 4.0f, BlurMaskFilter.Blur.NORMAL);
-        mShadowOffset = (int) (scale * 2.0f);
-        shadowBitmapPadding = (int) (scale * 4.0f);
+        mShadowBlurMaskFilter = new BlurMaskFilter(
+                res.getDimension(R.dimen.blur_size_click_shadow), BlurMaskFilter.Blur.NORMAL);
 
         mDrawPaint.setFilterBitmap(true);
         mDrawPaint.setAntiAlias(true);
@@ -71,10 +74,10 @@ public class HolographicOutlineHelper {
     }
 
     public static HolographicOutlineHelper obtain(Context context) {
-        if (INSTANCE == null) {
-            INSTANCE = new HolographicOutlineHelper(context);
+        if (sInstance == null) {
+            sInstance = new HolographicOutlineHelper(context);
         }
-        return INSTANCE;
+        return sInstance;
     }
 
     /**
@@ -153,51 +156,31 @@ public class HolographicOutlineHelper {
     }
 
     Bitmap createMediumDropShadow(BubbleTextView view) {
-        final Bitmap result = Bitmap.createBitmap(
-                view.getWidth() + shadowBitmapPadding + shadowBitmapPadding,
-                view.getHeight() + shadowBitmapPadding + shadowBitmapPadding + mShadowOffset,
-                Bitmap.Config.ARGB_8888);
-
-        mCanvas.setBitmap(result);
-
-        final Rect clipRect = sTempRect;
-        view.getDrawingRect(sTempRect);
-        // adjust the clip rect so that we don't include the text label
-        clipRect.bottom = view.getExtendedPaddingTop() - (int) BubbleTextView.PADDING_V
-                + view.getLayout().getLineTop(0);
-
-        // Draw the View into the bitmap.
-        // The translate of scrollX and scrollY is necessary when drawing TextViews, because
-        // they set scrollX and scrollY to large values to achieve centered text
-        mCanvas.save();
-        mCanvas.scale(view.getScaleX(), view.getScaleY(),
-                view.getWidth() / 2 + shadowBitmapPadding,
-                view.getHeight() / 2 + shadowBitmapPadding);
-        mCanvas.translate(-view.getScrollX() + shadowBitmapPadding,
-                -view.getScrollY() + shadowBitmapPadding);
-        mCanvas.clipRect(clipRect, Op.REPLACE);
-        view.draw(mCanvas);
-        mCanvas.restore();
-
-        int[] blurOffst = new int[2];
-        mBlurPaint.setMaskFilter(mShaowBlurMaskFilter);
-        Bitmap blurBitmap = result.extractAlpha(mBlurPaint, blurOffst);
-
-        mCanvas.save();
-        mCanvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
-        mCanvas.translate(blurOffst[0], blurOffst[1]);
-
-        mDrawPaint.setColor(Color.BLACK);
-        mDrawPaint.setAlpha(30);
-        mCanvas.drawBitmap(blurBitmap, 0, 0, mDrawPaint);
+        Drawable icon = view.getIcon();
+        Rect rect = icon.getBounds();
+
+        int bitmapWidth = (int) (rect.width() * view.getScaleX());
+        int bitmapHeight = (int) (rect.height() * view.getScaleY());
+
+        int key = (bitmapWidth << 16) | bitmapHeight;
+        Bitmap cache = mBitmapCache.get(key);
+        if (cache == null) {
+            cache = Bitmap.createBitmap(bitmapWidth, bitmapHeight, Bitmap.Config.ARGB_8888);
+            mCanvas.setBitmap(cache);
+            mBitmapCache.put(key, cache);
+        } else {
+            mCanvas.setBitmap(cache);
+            mCanvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
+        }
 
-        mDrawPaint.setAlpha(60);
-        mCanvas.drawBitmap(blurBitmap, 0, mShadowOffset, mDrawPaint);
+        mCanvas.save(Canvas.MATRIX_SAVE_FLAG);
+        mCanvas.scale(view.getScaleX(), view.getScaleY());
+        mCanvas.translate(-rect.left, -rect.top);
+        icon.draw(mCanvas);
         mCanvas.restore();
-
         mCanvas.setBitmap(null);
-        blurBitmap.recycle();
 
-        return result;
+        mBlurPaint.setMaskFilter(mShadowBlurMaskFilter);
+        return cache.extractAlpha(mBlurPaint, null);
     }
 }