From c495e611b9fa1fc6b47a647c714bbbf94dd63461 Mon Sep 17 00:00:00 2001
From: Rob Tsuk <robtsuk@google.com>
Date: Tue, 11 Nov 2014 15:44:13 -0800
Subject: [PATCH] Add a way to override Xfermode

Add a non-public API to Canvas/GLES20Canvas to provide a way to draw
the touch ripple animation without using a save layer.

Bug: 18226391
Change-Id: I6f8fb8938505e976892c4e14f6f864362c43e73c
---
 core/java/android/view/GLES20Canvas.java   | 11 ++++++++++
 core/jni/android_view_GLES20Canvas.cpp     |  8 ++++++++
 graphics/java/android/graphics/Canvas.java |  9 ++++++++
 libs/hwui/DisplayListRenderer.cpp          |  1 +
 libs/hwui/DisplayListRenderer.h            | 24 +++++++++++++++++++---
 5 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/core/java/android/view/GLES20Canvas.java b/core/java/android/view/GLES20Canvas.java
index 41a4a7c19d45b..1138aaba30878 100644
--- a/core/java/android/view/GLES20Canvas.java
+++ b/core/java/android/view/GLES20Canvas.java
@@ -988,4 +988,15 @@ class GLES20Canvas extends HardwareCanvas {
             int indexOffset, int indexCount, Paint paint) {
         // TODO: Implement
     }
+
+    @Override
+    public void setOverrideXfermode(PorterDuff.Mode xfermode) {
+        int xfermodeValue = -1;
+        if (xfermode != null) {
+            xfermodeValue = xfermode.nativeInt;
+        }
+        nSetOverrideXfermode(mRenderer, xfermodeValue);
+    }
+
+    private static native void nSetOverrideXfermode(long renderer, int xfermode);
 }
diff --git a/core/jni/android_view_GLES20Canvas.cpp b/core/jni/android_view_GLES20Canvas.cpp
index 78e92530d0dc0..814e1c86186a5 100644
--- a/core/jni/android_view_GLES20Canvas.cpp
+++ b/core/jni/android_view_GLES20Canvas.cpp
@@ -172,6 +172,12 @@ static jint android_view_GLES20Canvas_getMaxTextureHeight(JNIEnv* env, jobject c
     return Caches::getInstance().maxTextureSize;
 }
 
+static void android_view_GLES20Canvas_setOverrideXfermode(JNIEnv* env, jobject clazz,
+        jlong rendererPtr, int xfermode) {
+    DisplayListRenderer* renderer = reinterpret_cast<DisplayListRenderer*>(rendererPtr);
+    renderer->setOverrideXfermode(xfermode);
+}
+
 // ----------------------------------------------------------------------------
 // State
 // ----------------------------------------------------------------------------
@@ -953,6 +959,8 @@ static JNINativeMethod gMethods[] = {
     { "nGetMaximumTextureWidth",  "()I",       (void*) android_view_GLES20Canvas_getMaxTextureWidth },
     { "nGetMaximumTextureHeight", "()I",       (void*) android_view_GLES20Canvas_getMaxTextureHeight },
 
+    { "nSetOverrideXfermode", "(JI)V",       (void*) android_view_GLES20Canvas_setOverrideXfermode },
+
 #endif
 };
 
diff --git a/graphics/java/android/graphics/Canvas.java b/graphics/java/android/graphics/Canvas.java
index edf0fb9c48ce7..b9af794d2ef1c 100644
--- a/graphics/java/android/graphics/Canvas.java
+++ b/graphics/java/android/graphics/Canvas.java
@@ -249,6 +249,15 @@ public class Canvas {
     /** @hide */
     public void insertInorderBarrier() {}
 
+    /**
+     * Set a transfer mode that overrides any transfer modes
+     * in paints used for drawing. Pass null to disable this
+     * override. Only implemented in GLES20Canvas.
+     *
+     * @hide
+     */
+    public void setOverrideXfermode(@Nullable PorterDuff.Mode xfermode) {}
+
     /**
      * Return true if the device that the current layer draws into is opaque
      * (i.e. does not support per-pixel alpha).
diff --git a/libs/hwui/DisplayListRenderer.cpp b/libs/hwui/DisplayListRenderer.cpp
index 8887aa76ba2e8..f5247e7224e6e 100644
--- a/libs/hwui/DisplayListRenderer.cpp
+++ b/libs/hwui/DisplayListRenderer.cpp
@@ -40,6 +40,7 @@ DisplayListRenderer::DisplayListRenderer()
     , mTranslateY(0.0f)
     , mDeferredBarrierType(kBarrier_None)
     , mHighContrastText(false)
+    , mOverrideXfermode(-1)
     , mRestoreSaveCount(-1) {
 }
 
diff --git a/libs/hwui/DisplayListRenderer.h b/libs/hwui/DisplayListRenderer.h
index 6646da774e9bf..c8a974245069d 100644
--- a/libs/hwui/DisplayListRenderer.h
+++ b/libs/hwui/DisplayListRenderer.h
@@ -23,6 +23,7 @@
 #include <SkPath.h>
 #include <SkRegion.h>
 #include <SkTLazy.h>
+#include <SkPorterDuff.h>
 #include <cutils/compiler.h>
 
 #include "CanvasState.h"
@@ -189,6 +190,14 @@ public:
     virtual void onSnapshotRestored(const Snapshot& removed, const Snapshot& restored) { }
     virtual GLuint onGetTargetFbo() const { return -1; }
 
+    void setOverrideXfermode(int xfermode) {
+        if (xfermode != -1) {
+            SkPorterDuff::Mode porterDuffMode = static_cast<SkPorterDuff::Mode>(xfermode);
+            xfermode = SkPorterDuff::ToXfermodeMode(porterDuffMode);
+        }
+        mOverrideXfermode = xfermode;
+    };
+
 private:
 
     CanvasState mState;
@@ -253,10 +262,16 @@ private:
 
         // If there is a draw filter apply it here and store the modified paint
         // so that we don't need to modify the paint every time we access it.
-        SkTLazy<SkPaint> filteredPaint;
+        SkTLazy<SkPaint> localPaint;
         if (mDrawFilter.get()) {
-           paint = filteredPaint.init();
-           mDrawFilter->filter(filteredPaint.get(), SkDrawFilter::kPaint_Type);
+           paint = localPaint.set(*paint);
+           mDrawFilter->filter(localPaint.get(), SkDrawFilter::kPaint_Type);
+        }
+
+        if (mOverrideXfermode != -1) {
+            SkPaint* overriddenPaint = localPaint.set(*paint);
+            overriddenPaint->setXfermodeMode(static_cast<SkXfermode::Mode>(mOverrideXfermode));
+            paint = overriddenPaint;
         }
 
         // compute the hash key for the paint and check the cache.
@@ -334,6 +349,9 @@ private:
     DeferredBarrierType mDeferredBarrierType;
     bool mHighContrastText;
 
+    // -1 if unset, or SkXfermode::Mode value if set
+    int mOverrideXfermode;
+
     int mRestoreSaveCount;
 
     SkAutoTUnref<SkDrawFilter> mDrawFilter;