Add support for saveLayer().

saveLayer() is affected by the paint's alpha and xfermode.

Change-Id: I28693a9337052643adccdb4889a8f228d4e17903

7 files changed, 238 insertions, 53 deletions

diff --git a/libs/hwui/OpenGLRenderer.cpp b/libs/hwui/OpenGLRenderer.cpp
index 305c8c5..aa992c4 100644
--- a/libs/hwui/OpenGLRenderer.cpp
+++ b/libs/hwui/OpenGLRenderer.cpp
@@ -171,41 +171,45 @@ bool OpenGLRenderer::restoreSnapshot() {
     sp<Snapshot> previous = mSnapshot->previous;
 
     if (restoreLayer) {
-        // Unbind current FBO and restore previous one
-        // Most of the time, previous->fbo will be 0 to bind the default buffer
-        glBindFramebuffer(GL_FRAMEBUFFER, previous->fbo);
+        composeLayer(current, previous);
+    }
 
-        // Restore the clip from the previous snapshot
-        const Rect& clip = previous->getMappedClip();
-        glScissor(clip.left, mHeight - clip.bottom, clip.getWidth(), clip.getHeight());
+    mSnapshot = previous;
+    mSaveCount--;
 
-        // Compute the correct texture coordinates for the FBO texture
-        // The texture is currently as big as the window but drawn with
-        // a quad of the appropriate size
-        const Rect& layer = current->layer;
-        Rect texCoords(current->layer);
-        mSnapshot->transform.mapRect(texCoords);
+    return restoreClip;
+}
 
-        const float u1 = texCoords.left / float(mWidth);
-        const float v1 = (mHeight - texCoords.top) / float(mHeight);
-        const float u2 = texCoords.right / float(mWidth);
-        const float v2 = (mHeight - texCoords.bottom) / float(mHeight);
+void OpenGLRenderer::composeLayer(sp<Snapshot> current, sp<Snapshot> previous) {
+    // Unbind current FBO and restore previous one
+    // Most of the time, previous->fbo will be 0 to bind the default buffer
+    glBindFramebuffer(GL_FRAMEBUFFER, previous->fbo);
 
-        resetDrawTextureTexCoords(u1, v1, u2, v1);
+    // Restore the clip from the previous snapshot
+    const Rect& clip = previous->getMappedClip();
+    glScissor(clip.left, mHeight - clip.bottom, clip.getWidth(), clip.getHeight());
 
-        drawTextureRect(layer.left, layer.top, layer.right, layer.bottom,
-                current->texture, current->alpha);
+    // Compute the correct texture coordinates for the FBO texture
+    // The texture is currently as big as the window but drawn with
+    // a quad of the appropriate size
+    const Rect& layer = current->layer;
+    Rect texCoords(current->layer);
+    mSnapshot->transform.mapRect(texCoords);
 
-        resetDrawTextureTexCoords(0.0f, 1.0f, 1.0f, 0.0f);
+    const float u1 = texCoords.left / float(mWidth);
+    const float v1 = (mHeight - texCoords.top) / float(mHeight);
+    const float u2 = texCoords.right / float(mWidth);
+    const float v2 = (mHeight - texCoords.bottom) / float(mHeight);
 
-        glDeleteFramebuffers(1, &current->fbo);
-        glDeleteTextures(1, &current->texture);
-    }
+    resetDrawTextureTexCoords(u1, v1, u2, v1);
 
-    mSnapshot = previous;
-    mSaveCount--;
+    drawTextureRect(layer.left, layer.top, layer.right, layer.bottom,
+            current->texture, current->alpha, current->mode, true);
 
-    return restoreClip;
+    resetDrawTextureTexCoords(0.0f, 1.0f, 1.0f, 0.0f);
+
+    glDeleteFramebuffers(1, &current->fbo);
+    glDeleteTextures(1, &current->texture);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -214,25 +218,43 @@ bool OpenGLRenderer::restoreSnapshot() {
 
 int OpenGLRenderer::saveLayer(float left, float top, float right, float bottom,
         const SkPaint* p, int flags) {
-    // TODO Implement
-    return saveSnapshot();
+    int count = saveSnapshot();
+
+    int alpha = 255;
+    SkXfermode::Mode mode;
+
+    if (p) {
+        alpha = p->getAlpha();
+        const bool isMode = SkXfermode::IsMode(p->getXfermode(), &mode);
+        if (!isMode) {
+            // Assume SRC_OVER
+            mode = SkXfermode::kSrcOver_Mode;
+        }
+    } else {
+        mode = SkXfermode::kSrcOver_Mode;
+    }
+
+    createLayer(mSnapshot, left, top, right, bottom, alpha, mode, flags);
+
+    return count;
 }
 
 int OpenGLRenderer::saveLayerAlpha(float left, float top, float right, float bottom,
         int alpha, int flags) {
     int count = saveSnapshot();
+    createLayer(mSnapshot, left, top, right, bottom, alpha, SkXfermode::kSrcOver_Mode, flags);
+    return count;
+}
 
-    mSnapshot->flags |= Snapshot::kFlagIsLayer;
-    mSnapshot->alpha = alpha / 255.0f;
-    mSnapshot->layer.set(left, top, right, bottom);
-
+bool OpenGLRenderer::createLayer(sp<Snapshot> snapshot, float left, float top,
+        float right, float bottom, int alpha, SkXfermode::Mode mode,int flags) {
     // Generate the FBO and attach the texture
-    glGenFramebuffers(1, &mSnapshot->fbo);
-    glBindFramebuffer(GL_FRAMEBUFFER, mSnapshot->fbo);
+    glGenFramebuffers(1, &snapshot->fbo);
+    glBindFramebuffer(GL_FRAMEBUFFER, snapshot->fbo);
 
     // Generate the texture in which the FBO will draw
-    glGenTextures(1, &mSnapshot->texture);
-    glBindTexture(GL_TEXTURE_2D, mSnapshot->texture);
+    glGenTextures(1, &snapshot->texture);
+    glBindTexture(GL_TEXTURE_2D, snapshot->texture);
 
     // The FBO will not be scaled, so we can use lower quality filtering
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
@@ -255,17 +277,24 @@ int OpenGLRenderer::saveLayerAlpha(float left, float top, float right, float bot
 
     // Bind texture to FBO
     glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
-            mSnapshot->texture, 0);
+            snapshot->texture, 0);
 
     GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
     if (status != GL_FRAMEBUFFER_COMPLETE) {
         LOGD("Framebuffer incomplete %d", status);
 
-        glDeleteFramebuffers(1, &mSnapshot->fbo);
-        glDeleteTextures(1, &mSnapshot->texture);
+        glDeleteFramebuffers(1, &snapshot->fbo);
+        glDeleteTextures(1, &snapshot->texture);
+
+        return false;
     }
 
-    return count;
+    snapshot->flags |= Snapshot::kFlagIsLayer;
+    snapshot->mode = mode;
+    snapshot->alpha = alpha / 255.0f;
+    snapshot->layer.set(left, top, right, bottom);
+
+    return true;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -406,16 +435,20 @@ void OpenGLRenderer::drawColorRect(float left, float top, float right, float bot
 }
 
 void OpenGLRenderer::drawTextureRect(float left, float top, float right, float bottom,
-        GLuint texture, float alpha) {
+        GLuint texture, float alpha, SkXfermode::Mode mode, bool isPremultiplied) {
     mModelView.loadTranslate(left, top, 0.0f);
     mModelView.scale(right - left, bottom - top, 1.0f);
 
     mDrawTextureShader->use(&mOrthoMatrix[0], &mModelView.data[0], &mSnapshot->transform.data[0]);
 
-    // TODO Correctly set the blend function, based on texture format and xfermode
+    GLenum sourceMode = gBlends[mode].src;
+    if (!isPremultiplied && sourceMode == GL_ONE) {
+        sourceMode = GL_SRC_ALPHA;
+    }
+
+    // TODO: Try to disable blending when the texture is opaque and alpha == 1.0f
     glEnable(GL_BLEND);
-    // For not pre-multiplied sources
-    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+    glBlendFunc(sourceMode, gBlends[mode].dst);
 
     glBindTexture(GL_TEXTURE_2D, texture);
 
diff --git a/libs/hwui/OpenGLRenderer.h b/libs/hwui/OpenGLRenderer.h
index 85fa541..1af73c1 100644
--- a/libs/hwui/OpenGLRenderer.h
+++ b/libs/hwui/OpenGLRenderer.h
@@ -126,6 +126,34 @@ private:
     void setScissorFromClip();
 
     /**
+     * Compose the layer defined in the current snapshot with the layer
+     * defined by the previous snapshot.
+     *
+     * The current snapshot *must* be a layer (flag kFlagIsLayer set.)
+     *
+     * @param curent The current snapshot containing the layer to compose
+     * @param previous The previous snapshot to compose the current layer with
+     */
+    void composeLayer(sp<Snapshot> current, sp<Snapshot> previous);
+
+    /**
+     * Creates a new layer stored in the specified snapshot.
+     *
+     * @param snapshot The snapshot associated with the new layer
+     * @param left The left coordinate of the layer
+     * @param top The top coordinate of the layer
+     * @param right The right coordinate of the layer
+     * @param bottom The bottom coordinate of the layer
+     * @param alpha The translucency of the layer
+     * @param mode The blending mode of the layer
+     * @param flags The layer save flags
+     *
+     * @return True if the layer was successfully created, false otherwise
+     */
+    bool createLayer(sp<Snapshot> snapshot, float left, float top, float right, float bottom,
+            int alpha, SkXfermode::Mode mode, int flags);
+
+    /**
      * Draws a colored rectangle with the specified color. The specified coordinates
      * are transformed by the current snapshot's transform matrix.
      *
@@ -149,9 +177,11 @@ private:
      * @param bottom The bottom coordinate of the rectangle
      * @param texture The texture name to map onto the rectangle
      * @param alpha An additional translucency parameter, between 0.0f and 1.0f
+     * @param mode The blending mode
+     * @param isPremultiplied Indicates whether the texture has premultiplied alpha
      */
     void drawTextureRect(float left, float top, float right, float bottom, GLuint texture,
-            float alpha);
+            float alpha, SkXfermode::Mode mode, bool isPremultiplied = false);
 
     /**
      * Resets the texture coordinates stored in mDrawTextureVertices. Setting the values
diff --git a/libs/hwui/Snapshot.h b/libs/hwui/Snapshot.h
index 9a9be2d..ca91b34 100644
--- a/libs/hwui/Snapshot.h
+++ b/libs/hwui/Snapshot.h
@@ -20,6 +20,8 @@
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
 
+#include <SkXfermode.h>
+
 #include <utils/RefBase.h>
 
 #include "Matrix.h"
@@ -133,6 +135,11 @@ public:
      * Only set when the flag kFlagIsLayer is set.
      */
     float alpha;
+    /**
+     * Blending mode of the layer.
+     * Only set when the flag kFlagIsLayer is set.
+     */
+    SkXfermode::Mode mode;
 
 private:
     // Clipping rectangle mapped with the transform
diff --git a/tests/HwAccelerationTest/AndroidManifest.xml b/tests/HwAccelerationTest/AndroidManifest.xml
index 7dfa672..30ac8d6 100644
--- a/tests/HwAccelerationTest/AndroidManifest.xml
+++ b/tests/HwAccelerationTest/AndroidManifest.xml
@@ -22,8 +22,18 @@
         android:hardwareAccelerated="true">
 
         <activity
-                android:name="HwUiActivity"
-                android:label="_Layers">
+                android:name="AlphaLayersActivity"
+                android:label="_αLayers">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+        
+        <activity
+                android:name="LayersActivity"
+                android:label="_Layers"
+                android:theme="@android:style/Theme.Translucent">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />
diff --git a/tests/HwAccelerationTest/src/com/google/android/test/hwui/HwUiActivity.java b/tests/HwAccelerationTest/src/com/google/android/test/hwui/AlphaLayersActivity.java
index 85e3997..0217a05 100644
--- a/tests/HwAccelerationTest/src/com/google/android/test/hwui/HwUiActivity.java
+++ b/tests/HwAccelerationTest/src/com/google/android/test/hwui/AlphaLayersActivity.java
@@ -29,7 +29,7 @@ import android.view.animation.Animation;
 import android.widget.FrameLayout;
 
 @SuppressWarnings({"UnusedDeclaration"})
-public class HwUiActivity extends Activity {
+public class AlphaLayersActivity extends Activity {
     private static final String LOG_TAG = "HwUi";
 
     @Override
diff --git a/tests/HwAccelerationTest/src/com/google/android/test/hwui/LayersActivity.java b/tests/HwAccelerationTest/src/com/google/android/test/hwui/LayersActivity.java
new file mode 100644
index 0000000..437cd1c
--- /dev/null
+++ b/tests/HwAccelerationTest/src/com/google/android/test/hwui/LayersActivity.java
@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2010 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.google.android.test.hwui;
+
+import android.app.Activity;
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.Paint;
+import android.graphics.PorterDuff;
+import android.graphics.PorterDuffXfermode;
+import android.os.Bundle;
+import android.view.View;
+
+@SuppressWarnings({"UnusedDeclaration"})
+public class LayersActivity extends Activity {
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(new LayersView(this));
+    }
+
+    static class LayersView extends View {
+        private Paint mLayerPaint;
+        private final Paint mRectPaint;
+
+        LayersView(Context c) {
+            super(c);
+
+            mLayerPaint = new Paint();
+            mRectPaint = new Paint();
+        }
+
+        @Override
+        protected void onDraw(Canvas canvas) {
+            super.onDraw(canvas);
+            
+            canvas.translate(140.0f, 100.0f);
+
+            //canvas.drawRGB(255, 255, 255);
+            
+            int count = canvas.saveLayer(0.0f, 0.0f, 200.0f, 100.0f, mLayerPaint,
+                    Canvas.ALL_SAVE_FLAG);
+
+            mRectPaint.setColor(0xffff0000);
+            canvas.drawRect(0.0f, 0.0f, 200.0f, 100.0f, mRectPaint);
+
+            canvas.restoreToCount(count);
+            
+            canvas.translate(0.0f, 125.0f);
+            
+            count = canvas.saveLayer(0.0f, 0.0f, 200.0f, 100.0f, mLayerPaint,
+                    Canvas.ALL_SAVE_FLAG);
+
+            mRectPaint.setColor(0xff00ff00);
+            mRectPaint.setAlpha(50);
+            canvas.drawRect(0.0f, 0.0f, 200.0f, 100.0f, mRectPaint);
+
+            canvas.restoreToCount(count);
+
+            canvas.translate(25.0f, 125.0f);
+
+            mRectPaint.setColor(0xff0000ff);
+            mRectPaint.setAlpha(255);
+            canvas.drawRect(0.0f, 0.0f, 100.0f, 50.0f, mRectPaint);            
+            
+            mLayerPaint.setAlpha(127);
+            mLayerPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_OUT));
+            count = canvas.saveLayer(50.0f, 25.0f, 150.0f, 75.0f, mLayerPaint,
+                    Canvas.ALL_SAVE_FLAG);
+
+            mRectPaint.setColor(0xffff0000);
+            canvas.drawRect(50.0f, 25.0f, 150.0f, 75.0f, mRectPaint);
+
+            canvas.restoreToCount(count);
+            
+            canvas.translate(0.0f, 125.0f);
+
+            mRectPaint.setColor(0xff0000ff);
+            mRectPaint.setAlpha(255);
+            canvas.drawRect(0.0f, 0.0f, 100.0f, 50.0f, mRectPaint);            
+            
+            mLayerPaint.setColor(0xffff0000);
+            mLayerPaint.setAlpha(127);
+            mLayerPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_ATOP));
+            count = canvas.saveLayer(50.0f, 25.0f, 150.0f, 75.0f, mLayerPaint,
+                    Canvas.ALL_SAVE_FLAG);
+
+            mRectPaint.setColor(0xffff0000);
+            canvas.drawRect(50.0f, 25.0f, 150.0f, 75.0f, mRectPaint);
+
+            canvas.restoreToCount(count);
+            
+            mLayerPaint = new Paint();
+        }
+    }
+}
diff --git a/tests/HwAccelerationTest/src/com/google/android/test/hwui/XfermodeActivity.java b/tests/HwAccelerationTest/src/com/google/android/test/hwui/XfermodeActivity.java
index 440d622..8c81f02 100644
--- a/tests/HwAccelerationTest/src/com/google/android/test/hwui/XfermodeActivity.java
+++ b/tests/HwAccelerationTest/src/com/google/android/test/hwui/XfermodeActivity.java
@@ -35,11 +35,6 @@ public class XfermodeActivity extends Activity {
         
         setContentView(new XfermodesView(this));
     }
-    
-    @SuppressWarnings({"UnusedDeclaration"})
-    static int dipToPx(Context c, int dip) {
-        return (int) (c.getResources().getDisplayMetrics().density * dip + 0.5f);
-    }
 
     static class XfermodesView extends View {
         private final Paint mBluePaint;