Avoid extra saveLayer calls in RippleDrawable, fix docs

Also fixes opacity returned from InsetDrawable to accurately reflect
the transparent inset area and updates button to correctly use tint.

BUG: 18226391
Change-Id: Ia9a88d9d663990a6829d2f251c7f59ea2a79d816

5 files changed, 256 insertions, 198 deletions

diff --git a/core/res/res/drawable/btn_default_mtrl_shape.xml b/core/res/res/drawable/btn_default_mtrl_shape.xml
index 6d0f7f8c63c7..8a31d5ece132 100644
--- a/core/res/res/drawable/btn_default_mtrl_shape.xml
+++ b/core/res/res/drawable/btn_default_mtrl_shape.xml
@@ -21,9 +21,10 @@
        android:insetTop="@dimen/button_inset_vertical_material"
        android:insetRight="@dimen/button_inset_horizontal_material"
        android:insetBottom="@dimen/button_inset_vertical_material">
-    <shape android:shape="rectangle">
+    <shape android:shape="rectangle"
+           android:tint="?attr/colorButtonNormal">
         <corners android:radius="@dimen/control_corner_material" />
-        <solid android:color="?attr/colorButtonNormal" />
+        <solid android:color="@color/white" />
         <padding android:left="@dimen/button_padding_horizontal_material"
                  android:top="@dimen/button_padding_vertical_material"
                  android:right="@dimen/button_padding_horizontal_material"
diff --git a/graphics/java/android/graphics/drawable/InsetDrawable.java b/graphics/java/android/graphics/drawable/InsetDrawable.java
index b88d9e67b069..acfd427ebc93 100644
--- a/graphics/java/android/graphics/drawable/InsetDrawable.java
+++ b/graphics/java/android/graphics/drawable/InsetDrawable.java
@@ -30,6 +30,7 @@ import android.graphics.Canvas;
 import android.graphics.ColorFilter;
 import android.graphics.Insets;
 import android.graphics.Outline;
+import android.graphics.PixelFormat;
 import android.graphics.PorterDuff.Mode;
 import android.graphics.Rect;
 import android.util.AttributeSet;
@@ -317,7 +318,13 @@ public class InsetDrawable extends Drawable implements Drawable.Callback {
 
     @Override
     public int getOpacity() {
-        return mState.mDrawable.getOpacity();
+        final InsetState state = mState;
+        final int opacity = state.mDrawable.getOpacity();
+        if (opacity == PixelFormat.OPAQUE && (state.mInsetLeft > 0 || state.mInsetTop > 0
+                || state.mInsetRight > 0 || state.mInsetBottom > 0)) {
+            return PixelFormat.TRANSLUCENT;
+        }
+        return opacity;
     }
 
     @Override
diff --git a/graphics/java/android/graphics/drawable/Ripple.java b/graphics/java/android/graphics/drawable/Ripple.java
index 6731366f8a9a..a3a220c4b3c4 100644
--- a/graphics/java/android/graphics/drawable/Ripple.java
+++ b/graphics/java/android/graphics/drawable/Ripple.java
@@ -22,11 +22,8 @@ import android.animation.ObjectAnimator;
 import android.animation.TimeInterpolator;
 import android.graphics.Canvas;
 import android.graphics.CanvasProperty;
-import android.graphics.Color;
 import android.graphics.Paint;
-import android.graphics.Paint.Style;
 import android.graphics.Rect;
-import android.graphics.Xfermode;
 import android.util.MathUtils;
 import android.view.HardwareCanvas;
 import android.view.RenderNodeAnimator;
@@ -51,19 +48,12 @@ class Ripple {
     // Hardware animators.
     private final ArrayList<RenderNodeAnimator> mRunningAnimations =
             new ArrayList<RenderNodeAnimator>();
-    private final ArrayList<RenderNodeAnimator> mPendingAnimations =
-            new ArrayList<RenderNodeAnimator>();
 
     private final RippleDrawable mOwner;
 
     /** Bounds used for computing max radius. */
     private final Rect mBounds;
 
-    /** ARGB color for drawing this ripple. */
-    private int mColor;
-
-    private Xfermode mXfermode;
-
     /** Maximum ripple radius. */
     private float mOuterRadius;
 
@@ -112,6 +102,10 @@ class Ripple {
     /** Whether we were canceled externally and should avoid self-removal. */
     private boolean mCanceled;
 
+    private boolean mHasPendingHardwareExit;
+    private int mPendingRadiusDuration;
+    private int mPendingOpacityDuration;
+
     /**
      * Creates a new ripple.
      */
@@ -217,10 +211,6 @@ class Ripple {
      * Draws the ripple centered at (0,0) using the specified paint.
      */
     public boolean draw(Canvas c, Paint p) {
-        // Store the color and xfermode, we might need them later.
-        mColor = p.getColor();
-        mXfermode = p.getXfermode();
-
         final boolean canUseHardware = c.isHardwareAccelerated();
         if (mCanUseHardware != canUseHardware && mCanUseHardware) {
             // We've switched from hardware to non-hardware mode. Panic.
@@ -229,8 +219,8 @@ class Ripple {
         mCanUseHardware = canUseHardware;
 
         final boolean hasContent;
-        if (canUseHardware && mHardwareAnimating) {
-            hasContent = drawHardware((HardwareCanvas) c);
+        if (canUseHardware && (mHardwareAnimating || mHasPendingHardwareExit)) {
+            hasContent = drawHardware((HardwareCanvas) c, p);
         } else {
             hasContent = drawSoftware(c, p);
         }
@@ -238,24 +228,10 @@ class Ripple {
         return hasContent;
     }
 
-    private boolean drawHardware(HardwareCanvas c) {
-        // If we have any pending hardware animations, cancel any running
-        // animations and start those now.
-        final ArrayList<RenderNodeAnimator> pendingAnimations = mPendingAnimations;
-        final int N = pendingAnimations.size();
-        if (N > 0) {
+    private boolean drawHardware(HardwareCanvas c, Paint p) {
+        if (mHasPendingHardwareExit) {
             cancelHardwareAnimations(false);
-
-            // We canceled old animations, but we're about to run new ones.
-            mHardwareAnimating = true;
-
-            for (int i = 0; i < N; i++) {
-                pendingAnimations.get(i).setTarget(c);
-                pendingAnimations.get(i).start();
-            }
-
-            mRunningAnimations.addAll(pendingAnimations);
-            pendingAnimations.clear();
+            startPendingHardwareExit(c, p);
         }
 
         c.drawCircle(mPropX, mPropY, mPropRadius, mPropPaint);
@@ -347,8 +323,6 @@ class Ripple {
      * Starts the exit animation.
      */
     public void exit() {
-        cancel();
-
         final float radius = MathUtils.lerp(0, mOuterRadius, mTweenRadius);
         final float remaining;
         if (mAnimRadius != null && mAnimRadius.isRunning()) {
@@ -357,19 +331,33 @@ class Ripple {
             remaining = mOuterRadius;
         }
 
+        cancel();
+
         final int radiusDuration = (int) (1000 * Math.sqrt(remaining / (WAVE_TOUCH_UP_ACCELERATION
                 + WAVE_TOUCH_DOWN_ACCELERATION) * mDensity) + 0.5);
         final int opacityDuration = (int) (1000 * mOpacity / WAVE_OPACITY_DECAY_VELOCITY + 0.5f);
 
         if (mCanUseHardware) {
-            exitHardware(radiusDuration, opacityDuration);
+            createPendingHardwareExit(radiusDuration, opacityDuration);
         } else {
             exitSoftware(radiusDuration, opacityDuration);
         }
     }
 
-    private void exitHardware(int radiusDuration, int opacityDuration) {
-        mPendingAnimations.clear();
+    private void createPendingHardwareExit(int radiusDuration, int opacityDuration) {
+        mHasPendingHardwareExit = true;
+        mPendingRadiusDuration = radiusDuration;
+        mPendingOpacityDuration = opacityDuration;
+
+        // The animation will start on the next draw().
+        invalidateSelf();
+    }
+
+    private void startPendingHardwareExit(HardwareCanvas c, Paint p) {
+        mHasPendingHardwareExit = false;
+
+        final int radiusDuration = mPendingRadiusDuration;
+        final int opacityDuration = mPendingOpacityDuration;
 
         final float startX = MathUtils.lerp(
                 mClampedStartingX - mBounds.exactCenterX(), mOuterX, mTweenX);
@@ -377,12 +365,8 @@ class Ripple {
                 mClampedStartingY - mBounds.exactCenterY(), mOuterY, mTweenY);
 
         final float startRadius = MathUtils.lerp(0, mOuterRadius, mTweenRadius);
-        final Paint paint = getTempPaint();
-        paint.setAntiAlias(true);
-        paint.setColor(mColor);
-        paint.setXfermode(mXfermode);
-        paint.setAlpha((int) (Color.alpha(mColor) * mOpacity + 0.5f));
-        paint.setStyle(Style.FILL);
+        final Paint paint = getTempPaint(p);
+        paint.setAlpha((int) (paint.getAlpha() * mOpacity + 0.5f));
         mPropPaint = CanvasProperty.createPaint(paint);
         mPropRadius = CanvasProperty.createFloat(startRadius);
         mPropX = CanvasProperty.createFloat(startX);
@@ -391,25 +375,33 @@ class Ripple {
         final RenderNodeAnimator radiusAnim = new RenderNodeAnimator(mPropRadius, mOuterRadius);
         radiusAnim.setDuration(radiusDuration);
         radiusAnim.setInterpolator(DECEL_INTERPOLATOR);
+        radiusAnim.setTarget(c);
+        radiusAnim.start();
 
         final RenderNodeAnimator xAnim = new RenderNodeAnimator(mPropX, mOuterX);
         xAnim.setDuration(radiusDuration);
         xAnim.setInterpolator(DECEL_INTERPOLATOR);
+        xAnim.setTarget(c);
+        xAnim.start();
 
         final RenderNodeAnimator yAnim = new RenderNodeAnimator(mPropY, mOuterY);
         yAnim.setDuration(radiusDuration);
         yAnim.setInterpolator(DECEL_INTERPOLATOR);
+        yAnim.setTarget(c);
+        yAnim.start();
 
         final RenderNodeAnimator opacityAnim = new RenderNodeAnimator(mPropPaint,
                 RenderNodeAnimator.PAINT_ALPHA, 0);
         opacityAnim.setDuration(opacityDuration);
         opacityAnim.setInterpolator(LINEAR_INTERPOLATOR);
         opacityAnim.addListener(mAnimationListener);
+        opacityAnim.setTarget(c);
+        opacityAnim.start();
 
-        mPendingAnimations.add(radiusAnim);
-        mPendingAnimations.add(opacityAnim);
-        mPendingAnimations.add(xAnim);
-        mPendingAnimations.add(yAnim);
+        mRunningAnimations.add(radiusAnim);
+        mRunningAnimations.add(opacityAnim);
+        mRunningAnimations.add(xAnim);
+        mRunningAnimations.add(yAnim);
 
         mHardwareAnimating = true;
 
@@ -418,8 +410,6 @@ class Ripple {
         mTweenX = 1;
         mTweenY = 1;
         mTweenRadius = 1;
-
-        invalidateSelf();
     }
 
     /**
@@ -455,10 +445,11 @@ class Ripple {
         }
     }
 
-    private Paint getTempPaint() {
+    private Paint getTempPaint(Paint original) {
         if (mTempPaint == null) {
             mTempPaint = new Paint();
         }
+        mTempPaint.set(original);
         return mTempPaint;
     }
 
@@ -539,10 +530,7 @@ class Ripple {
         }
         runningAnimations.clear();
 
-        if (cancelPending && !mPendingAnimations.isEmpty()) {
-            mPendingAnimations.clear();
-        }
-
+        mHasPendingHardwareExit = false;
         mHardwareAnimating = false;
     }
 
diff --git a/graphics/java/android/graphics/drawable/RippleBackground.java b/graphics/java/android/graphics/drawable/RippleBackground.java
index 69847b54cd44..665d736d985d 100644
--- a/graphics/java/android/graphics/drawable/RippleBackground.java
+++ b/graphics/java/android/graphics/drawable/RippleBackground.java
@@ -24,9 +24,7 @@ import android.graphics.Canvas;
 import android.graphics.CanvasProperty;
 import android.graphics.Color;
 import android.graphics.Paint;
-import android.graphics.Paint.Style;
 import android.graphics.Rect;
-import android.graphics.Xfermode;
 import android.util.MathUtils;
 import android.view.HardwareCanvas;
 import android.view.RenderNodeAnimator;
@@ -53,8 +51,6 @@ class RippleBackground {
     // Hardware animators.
     private final ArrayList<RenderNodeAnimator> mRunningAnimations =
             new ArrayList<RenderNodeAnimator>();
-    private final ArrayList<RenderNodeAnimator> mPendingAnimations =
-            new ArrayList<RenderNodeAnimator>();
 
     private final RippleDrawable mOwner;
 
@@ -64,8 +60,6 @@ class RippleBackground {
     /** ARGB color for drawing this ripple. */
     private int mColor;
 
-    private Xfermode mXfermode;
-
     /** Maximum ripple radius. */
     private float mOuterRadius;
 
@@ -98,6 +92,11 @@ class RippleBackground {
     /** Whether we have an explicit maximum radius. */
     private boolean mHasMaxRadius;
 
+    private boolean mHasPendingHardwareExit;
+    private int mPendingOpacityDuration;
+    private int mPendingInflectionDuration;
+    private int mPendingInflectionOpacity;
+
     /**
      * Creates a new ripple.
      */
@@ -144,9 +143,7 @@ class RippleBackground {
      * Draws the ripple centered at (0,0) using the specified paint.
      */
     public boolean draw(Canvas c, Paint p) {
-        // Store the color and xfermode, we might need them later.
         mColor = p.getColor();
-        mXfermode = p.getXfermode();
 
         final boolean canUseHardware = c.isHardwareAccelerated();
         if (mCanUseHardware != canUseHardware && mCanUseHardware) {
@@ -156,8 +153,8 @@ class RippleBackground {
         mCanUseHardware = canUseHardware;
 
         final boolean hasContent;
-        if (canUseHardware && mHardwareAnimating) {
-            hasContent = drawHardware((HardwareCanvas) c);
+        if (canUseHardware && (mHardwareAnimating || mHasPendingHardwareExit)) {
+            hasContent = drawHardware((HardwareCanvas) c, p);
         } else {
             hasContent = drawSoftware(c, p);
         }
@@ -169,24 +166,10 @@ class RippleBackground {
         return (mCanUseHardware && mHardwareAnimating) || (mOuterOpacity > 0 && mOuterRadius > 0);
     }
 
-    private boolean drawHardware(HardwareCanvas c) {
-        // If we have any pending hardware animations, cancel any running
-        // animations and start those now.
-        final ArrayList<RenderNodeAnimator> pendingAnimations = mPendingAnimations;
-        final int N = pendingAnimations.size();
-        if (N > 0) {
+    private boolean drawHardware(HardwareCanvas c, Paint p) {
+        if (mHasPendingHardwareExit) {
             cancelHardwareAnimations(false);
-
-            // We canceled old animations, but we're about to run new ones.
-            mHardwareAnimating = true;
-
-            for (int i = 0; i < N; i++) {
-                pendingAnimations.get(i).setTarget(c);
-                pendingAnimations.get(i).start();
-            }
-
-            mRunningAnimations.addAll(pendingAnimations);
-            pendingAnimations.clear();
+            startPendingHardwareExit(c, p);
         }
 
         c.drawCircle(mPropOuterX, mPropOuterY, mPropOuterRadius, mPropOuterPaint);
@@ -263,21 +246,32 @@ class RippleBackground {
                 + inflectionDuration * outerOpacityVelocity * outerSizeInfluence / 1000) + 0.5f);
 
         if (mCanUseHardware) {
-            exitHardware(opacityDuration, inflectionDuration, inflectionOpacity);
+            createPendingHardwareExit(opacityDuration, inflectionDuration, inflectionOpacity);
         } else {
             exitSoftware(opacityDuration, inflectionDuration, inflectionOpacity);
         }
     }
 
-    private void exitHardware(int opacityDuration, int inflectionDuration, int inflectionOpacity) {
-        mPendingAnimations.clear();
+    private void createPendingHardwareExit(
+            int opacityDuration, int inflectionDuration, int inflectionOpacity) {
+        mHasPendingHardwareExit = true;
+        mPendingOpacityDuration = opacityDuration;
+        mPendingInflectionDuration = inflectionDuration;
+        mPendingInflectionOpacity = inflectionOpacity;
+
+        // The animation will start on the next draw().
+        invalidateSelf();
+    }
+
+    private void startPendingHardwareExit(HardwareCanvas c, Paint p) {
+        mHasPendingHardwareExit = false;
+
+        final int opacityDuration = mPendingOpacityDuration;
+        final int inflectionDuration = mPendingInflectionDuration;
+        final int inflectionOpacity = mPendingInflectionOpacity;
 
-        final Paint outerPaint = getTempPaint();
-        outerPaint.setAntiAlias(true);
-        outerPaint.setXfermode(mXfermode);
-        outerPaint.setColor(mColor);
-        outerPaint.setAlpha((int) (Color.alpha(mColor) * mOuterOpacity + 0.5f));
-        outerPaint.setStyle(Style.FILL);
+        final Paint outerPaint = getTempPaint(p);
+        outerPaint.setAlpha((int) (outerPaint.getAlpha() * mOuterOpacity + 0.5f));
         mPropOuterPaint = CanvasProperty.createPaint(outerPaint);
         mPropOuterRadius = CanvasProperty.createFloat(mOuterRadius);
         mPropOuterX = CanvasProperty.createFloat(mOuterX);
@@ -301,8 +295,10 @@ class RippleBackground {
                 outerFadeOutAnim.setStartDelay(inflectionDuration);
                 outerFadeOutAnim.setStartValue(inflectionOpacity);
                 outerFadeOutAnim.addListener(mAnimationListener);
+                outerFadeOutAnim.setTarget(c);
+                outerFadeOutAnim.start();
 
-                mPendingAnimations.add(outerFadeOutAnim);
+                mRunningAnimations.add(outerFadeOutAnim);
             } else {
                 outerOpacityAnim.addListener(mAnimationListener);
             }
@@ -314,14 +310,15 @@ class RippleBackground {
             outerOpacityAnim.addListener(mAnimationListener);
         }
 
-        mPendingAnimations.add(outerOpacityAnim);
+        outerOpacityAnim.setTarget(c);
+        outerOpacityAnim.start();
+
+        mRunningAnimations.add(outerOpacityAnim);
 
         mHardwareAnimating = true;
 
         // Set up the software values to match the hardware end values.
         mOuterOpacity = 0;
-
-        invalidateSelf();
     }
 
     /**
@@ -340,10 +337,11 @@ class RippleBackground {
         }
     }
 
-    private Paint getTempPaint() {
+    private Paint getTempPaint(Paint original) {
         if (mTempPaint == null) {
             mTempPaint = new Paint();
         }
+        mTempPaint.set(original);
         return mTempPaint;
     }
 
@@ -422,10 +420,7 @@ class RippleBackground {
         }
         runningAnimations.clear();
 
-        if (cancelPending && !mPendingAnimations.isEmpty()) {
-            mPendingAnimations.clear();
-        }
-
+        mHasPendingHardwareExit = false;
         mHardwareAnimating = false;
     }
 
diff --git a/graphics/java/android/graphics/drawable/RippleDrawable.java b/graphics/java/android/graphics/drawable/RippleDrawable.java
index d5d5d5139b74..13e3d54c3476 100644
--- a/graphics/java/android/graphics/drawable/RippleDrawable.java
+++ b/graphics/java/android/graphics/drawable/RippleDrawable.java
@@ -27,15 +27,19 @@ import android.content.res.ColorStateList;
 import android.content.res.Resources;
 import android.content.res.Resources.Theme;
 import android.content.res.TypedArray;
+import android.graphics.Bitmap;
+import android.graphics.BitmapShader;
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.ColorFilter;
+import android.graphics.Matrix;
 import android.graphics.Outline;
 import android.graphics.Paint;
 import android.graphics.PixelFormat;
-import android.graphics.PorterDuff.Mode;
-import android.graphics.PorterDuffXfermode;
+import android.graphics.PorterDuff;
+import android.graphics.PorterDuffColorFilter;
 import android.graphics.Rect;
+import android.graphics.Shader;
 import android.util.AttributeSet;
 import android.util.DisplayMetrics;
 
@@ -56,7 +60,7 @@ import java.util.Arrays;
  * &ltripple android:color="#ffff0000">
  *   &ltitem android:id="@android:id/mask"
  *         android:drawable="@android:color/white" />
- * &ltripple /></code>
+ * &lt/ripple></code>
  * </pre>
  * <p>
  * If a mask layer is set, the ripple effect will be masked against that layer
@@ -65,15 +69,15 @@ import java.util.Arrays;
  * If no mask layer is set, the ripple effect is masked against the composite
  * of the child layers.
  * <pre>
- * <code>&lt!-- A blue ripple drawn atop a black rectangle. --/>
+ * <code>&lt!-- A green ripple drawn atop a black rectangle. --/>
  * &ltripple android:color="#ff00ff00">
  *   &ltitem android:drawable="@android:color/black" />
- * &ltripple />
+ * &lt/ripple>
  *
- * &lt!-- A red ripple drawn atop a drawable resource. --/>
- * &ltripple android:color="#ff00ff00">
+ * &lt!-- A blue ripple drawn atop a drawable resource. --/>
+ * &ltripple android:color="#ff0000ff">
  *   &ltitem android:drawable="@drawable/my_drawable" />
- * &ltripple /></code>
+ * &lt/ripple></code>
  * </pre>
  * <p>
  * If no child layers or mask is specified and the ripple is set as a View
@@ -81,16 +85,17 @@ import java.util.Arrays;
  * background within the View's hierarchy. In this case, the drawing region
  * may extend outside of the Drawable bounds.
  * <pre>
- * <code>&lt!-- An unbounded green ripple. --/>
- * &ltripple android:color="#ff0000ff" /></code>
+ * <code>&lt!-- An unbounded red ripple. --/>
+ * &ltripple android:color="#ffff0000" /></code>
  * </pre>
  *
  * @attr ref android.R.styleable#RippleDrawable_color
  */
 public class RippleDrawable extends LayerDrawable {
-    private static final PorterDuffXfermode DST_IN = new PorterDuffXfermode(Mode.DST_IN);
-    private static final PorterDuffXfermode SRC_ATOP = new PorterDuffXfermode(Mode.SRC_ATOP);
-    private static final PorterDuffXfermode SRC_OVER = new PorterDuffXfermode(Mode.SRC_OVER);
+    private static final int MASK_UNKNOWN = -1;
+    private static final int MASK_NONE = 0;
+    private static final int MASK_CONTENT = 1;
+    private static final int MASK_EXPLICIT = 2;
 
     /**
      * Constant for automatically determining the maximum ripple radius.
@@ -123,6 +128,13 @@ public class RippleDrawable extends LayerDrawable {
     /** The current background. May be actively animating or pending entry. */
     private RippleBackground mBackground;
 
+    private Bitmap mMaskBuffer;
+    private BitmapShader mMaskShader;
+    private Canvas mMaskCanvas;
+    private Matrix mMaskMatrix;
+    private PorterDuffColorFilter mMaskColorFilter;
+    private boolean mHasValidMask;
+
     /** Whether we expect to draw a background when visible. */
     private boolean mBackgroundActive;
 
@@ -147,9 +159,6 @@ public class RippleDrawable extends LayerDrawable {
     /** Paint used to control appearance of ripples. */
     private Paint mRipplePaint;
 
-    /** Paint used to control reveal layer masking. */
-    private Paint mMaskingPaint;
-
     /** Target density of the display into which ripples are drawn. */
     private float mDensity = 1.0f;
 
@@ -615,37 +624,116 @@ public class RippleDrawable extends LayerDrawable {
      */
     @Override
     public void draw(@NonNull Canvas canvas) {
-        final boolean hasMask = mMask != null;
-        final boolean hasRipples = mRipple != null || mExitingRipplesCount > 0
-                || (mBackground != null && mBackground.shouldDraw());
-
         // Clip to the dirty bounds, which will be the drawable bounds if we
         // have a mask or content and the ripple bounds if we're projecting.
         final Rect bounds = getDirtyBounds();
         final int saveCount = canvas.save(Canvas.CLIP_SAVE_FLAG);
         canvas.clipRect(bounds);
 
-        // If we have content, draw it first. If we have ripples and no mask,
-        // we'll draw it into a SRC_OVER layer so that we can mask ripples
-        // against it using SRC_IN.
-        final boolean hasContentLayer = drawContent(canvas, bounds, hasRipples, hasMask);
-
-        // Next, try to draw the ripples. If we have a non-opaque mask, we'll
-        // draw the ripples into a SRC_OVER layer, draw the mask into a DST_IN
-        // layer, and blend.
-        if (hasRipples) {
-            final boolean hasNonOpaqueMask = hasMask && mMask.getOpacity() != PixelFormat.OPAQUE;
-            final boolean hasRippleLayer = drawBackgroundAndRipples(canvas, bounds,
-                    hasNonOpaqueMask, hasContentLayer);
-
-            // If drawing ripples created a layer, we have a non-opaque mask
-            // that needs to be blended on top of the ripples with DST_IN.
-            if (hasRippleLayer) {
-                drawMaskingLayer(canvas, bounds, DST_IN);
+        drawContent(canvas);
+        drawBackgroundAndRipples(canvas);
+
+        canvas.restoreToCount(saveCount);
+    }
+
+    @Override
+    public void invalidateSelf() {
+        super.invalidateSelf();
+
+        // Force the mask to update on the next draw().
+        mHasValidMask = false;
+    }
+
+    /**
+     * @return whether we need to use a mask
+     */
+    private void updateMaskShaderIfNeeded() {
+        if (mHasValidMask) {
+            return;
+        }
+
+        final int maskType = getMaskType();
+        if (maskType == MASK_UNKNOWN) {
+            return;
+        }
+
+        mHasValidMask = true;
+
+        if (maskType == MASK_NONE) {
+            if (mMaskBuffer != null) {
+                mMaskBuffer.recycle();
+                mMaskBuffer = null;
+                mMaskShader = null;
+                mMaskCanvas = null;
             }
+            mMaskMatrix = null;
+            mMaskColorFilter = null;
+            return;
         }
 
-        canvas.restoreToCount(saveCount);
+        // Ensure we have a correctly-sized buffer.
+        final Rect bounds = getBounds();
+        if (mMaskBuffer == null
+                || mMaskBuffer.getWidth() != bounds.width()
+                || mMaskBuffer.getHeight() != bounds.height()) {
+            if (mMaskBuffer != null) {
+                mMaskBuffer.recycle();
+            }
+
+            mMaskBuffer = Bitmap.createBitmap(
+                    bounds.width(), bounds.height(), Bitmap.Config.ALPHA_8);
+            mMaskShader = new BitmapShader(mMaskBuffer,
+                    Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
+            mMaskCanvas = new Canvas(mMaskBuffer);
+        } else {
+            mMaskBuffer.eraseColor(Color.TRANSPARENT);
+        }
+
+        if (mMaskMatrix == null) {
+            mMaskMatrix = new Matrix();
+        } else {
+            mMaskMatrix.reset();
+        }
+
+        if (mMaskColorFilter == null) {
+            mMaskColorFilter = new PorterDuffColorFilter(0, PorterDuff.Mode.SRC_IN);
+        }
+
+        // Draw the appropriate mask.
+        if (maskType == MASK_EXPLICIT) {
+            drawMask(mMaskCanvas);
+        } else if (maskType == MASK_CONTENT) {
+            drawContent(mMaskCanvas);
+        }
+    }
+
+    private int getMaskType() {
+        if (mRipple == null && mExitingRipplesCount <= 0
+                && (mBackground == null || !mBackground.shouldDraw())) {
+            // We might need a mask later.
+            return MASK_UNKNOWN;
+        }
+
+        if (mMask != null) {
+            if (mMask.getOpacity() == PixelFormat.OPAQUE) {
+                // Clipping handles opaque explicit masks.
+                return MASK_NONE;
+            } else {
+                return MASK_EXPLICIT;
+            }
+        }
+
+        // Check for non-opaque, non-mask content.
+        final ChildDrawable[] array = mLayerState.mChildren;
+        final int count = mLayerState.mNum;
+        for (int i = 0; i < count; i++) {
+            if (array[i].mDrawable.getOpacity() != PixelFormat.OPAQUE) {
+                return MASK_CONTENT;
+            }
+        }
+
+        // Clipping handles opaque content.
+        return MASK_NONE;
     }
 
     /**
@@ -678,65 +766,65 @@ public class RippleDrawable extends LayerDrawable {
         return -1;
     }
 
-    private boolean drawContent(Canvas canvas, Rect bounds, boolean hasRipples, boolean hasMask) {
+    private void drawContent(Canvas canvas) {
+        // Draw everything except the mask.
         final ChildDrawable[] array = mLayerState.mChildren;
         final int count = mLayerState.mNum;
-
-        boolean needsLayer = false;
-
-        if (hasRipples && !hasMask) {
-            // If we only have opaque content, we don't really need a layer
-            // because the ripples will be clipped to the drawable bounds.
-            for (int i = 0; i < count; i++) {
-                if (array[i].mDrawable.getOpacity() != PixelFormat.OPAQUE) {
-                    needsLayer = true;
-                    break;
-                }
-            }
-        }
-
-        if (needsLayer) {
-            canvas.saveLayer(bounds.left, bounds.top, bounds.right, bounds.bottom,
-                    getMaskingPaint(SRC_OVER));
-        }
-
-        // Draw everything except the mask.
         for (int i = 0; i < count; i++) {
             if (array[i].mId != R.id.mask) {
                 array[i].mDrawable.draw(canvas);
             }
         }
-
-        return needsLayer;
     }
 
-    private boolean drawBackgroundAndRipples(
-            Canvas canvas, Rect bounds, boolean hasNonOpaqueMask, boolean hasContentLayer) {
-        if (hasNonOpaqueMask) {
-            final Paint p = getMaskingPaint(SRC_OVER);
-            canvas.saveLayer(bounds.left, bounds.top, bounds.right, bounds.bottom, p);
+    private void drawBackgroundAndRipples(Canvas canvas) {
+        final Ripple active = mRipple;
+        final RippleBackground background = mBackground;
+        final int count = mExitingRipplesCount;
+        if (active == null && count <= 0 && (background == null || !background.shouldDraw())) {
+            // Move along, nothing to draw here.
+            return;
         }
 
-        final PorterDuffXfermode mode = hasContentLayer ? SRC_ATOP : SRC_OVER;
         final float x = mHotspotBounds.exactCenterX();
         final float y = mHotspotBounds.exactCenterY();
         canvas.translate(x, y);
 
-        final Paint p = getRipplePaint();
-        p.setXfermode(mode);
+        updateMaskShaderIfNeeded();
+
+        // Position the shader to account for canvas translation.
+        if (mMaskShader != null) {
+            mMaskMatrix.setTranslate(-x, -y);
+            mMaskShader.setLocalMatrix(mMaskMatrix);
+        }
 
         // Grab the color for the current state and cut the alpha channel in
         // half so that the ripple and background together yield full alpha.
         final int color = mState.mColor.getColorForState(getState(), Color.BLACK);
-        final int alpha = (Color.alpha(color) / 2) << 24;
-        p.setColor(color & 0xFFFFFF | alpha);
+        final int halfAlpha = (Color.alpha(color) / 2) << 24;
+        final Paint p = getRipplePaint();
+
+        if (mMaskColorFilter != null) {
+            // The ripple timing depends on the paint's alpha value, so we need
+            // to push just the alpha channel into the paint and let the filter
+            // handle the full-alpha color.
+            final int fullAlphaColor = color | (0xFF << 24);
+            mMaskColorFilter.setColor(fullAlphaColor);
+
+            p.setColor(halfAlpha);
+            p.setColorFilter(mMaskColorFilter);
+            p.setShader(mMaskShader);
+        } else {
+            final int halfAlphaColor = (color & 0xFFFFFF) | halfAlpha;
+            p.setColor(halfAlphaColor);
+            p.setColorFilter(null);
+            p.setShader(null);
+        }
 
-        final RippleBackground background = mBackground;
         if (background != null && background.shouldDraw()) {
             background.draw(canvas, p);
         }
 
-        final int count = mExitingRipplesCount;
         if (count > 0) {
             final Ripple[] ripples = mExitingRipples;
             for (int i = 0; i < count; i++) {
@@ -744,27 +832,15 @@ public class RippleDrawable extends LayerDrawable {
             }
         }
 
-        final Ripple active = mRipple;
         if (active != null) {
             active.draw(canvas, p);
         }
 
         canvas.translate(-x, -y);
-
-        // Returns true if a layer was created.
-        return hasNonOpaqueMask;
     }
 
-    private int drawMaskingLayer(Canvas canvas, Rect bounds, PorterDuffXfermode mode) {
-        final int restoreToCount = canvas.saveLayer(bounds.left, bounds.top,
-                bounds.right, bounds.bottom, getMaskingPaint(mode));
-
-        // Ensure that DST_IN blends using the entire layer.
-        canvas.drawColor(Color.TRANSPARENT);
-
+    private void drawMask(Canvas canvas) {
         mMask.draw(canvas);
-
-        return restoreToCount;
     }
 
     private Paint getRipplePaint() {
@@ -776,15 +852,6 @@ public class RippleDrawable extends LayerDrawable {
         return mRipplePaint;
     }
 
-    private Paint getMaskingPaint(PorterDuffXfermode xfermode) {
-        if (mMaskingPaint == null) {
-            mMaskingPaint = new Paint();
-        }
-        mMaskingPaint.setXfermode(xfermode);
-        mMaskingPaint.setAlpha(0xFF);
-        return mMaskingPaint;
-    }
-
     @Override
     public Rect getDirtyBounds() {
         if (isProjected()) {