Use SkImage as a backing store for copying 2d Contexts to ImageBitmaps.

Source/core/page/ImageBitmap.cpp

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/page/ImageBitmap.h"
 
 #include "core/html/HTMLCanvasElement.h"
 #include "core/html/HTMLImageElement.h"
 #include "core/html/HTMLVideoElement.h"
@@ skipping 16 matching lines @@
 
 static inline PassRefPtr<BitmapImage> cropImage(Image* image, IntRect cropRect)
 {
     SkBitmap cropped;
     image->nativeImageForCurrentFrame()->bitmap().extractSubset(&cropped, cropRect);
     return BitmapImage::create(NativeImageSkia::create(cropped));
 }
 
 ImageBitmap::ImageBitmap(HTMLImageElement* image, IntRect cropRect)
     : m_bitmapOffset(max(0, -cropRect.x()), max(0, -cropRect.y()))
-    , m_size(cropRect.size())
+    , m_cropRect(cropRect)
+    , m_derivedFromCanvas(0)

[Justin Novosad, 2013/07/22 15:35:41]

this is a bool, so initialize it with false instead of 0.

 {
     Image* bitmapImage = image->cachedImage()->image();
-    m_bitmap = cropImage(bitmapImage, cropRect).get();
+    m_bitmap = cropImage(bitmapImage, cropRect);
+    m_bitmapSize = IntSize(m_bitmap->size());
 
     ScriptWrappable::init(this);
 }
 
 ImageBitmap::ImageBitmap(HTMLVideoElement* video, IntRect cropRect)
     : m_bitmapOffset(max(0, -cropRect.x()), max(0, -cropRect.y()))
-    , m_size(cropRect.size())
+    , m_cropRect(cropRect)
+    , m_derivedFromCanvas(0)
 {
     IntRect videoRect = IntRect(IntPoint(), video->player()->naturalSize());
     IntRect srcRect = intersection(cropRect, videoRect);
     IntRect dstRect(IntPoint(), srcRect.size());
 
     m_buffer = ImageBuffer::create(videoRect.size());
     GraphicsContext* c = m_buffer->context();
     c->clip(dstRect);
     c->translate(-srcRect.x(), -srcRect.y());
     video->paintCurrentFrameInContext(c, videoRect);
-    m_bitmap = static_cast<BitmapImage*>(m_buffer->copyImage(DontCopyBackingStore).get());
+    m_bitmap = m_buffer->copyImage(DontCopyBackingStore);
+    m_bitmapSize = IntSize(m_bitmap->size());
 
     ScriptWrappable::init(this);
 }
 
 ImageBitmap::ImageBitmap(HTMLCanvasElement* canvas, IntRect cropRect)
     : m_bitmapOffset(max(0, -cropRect.x()), max(0, -cropRect.y()))
-    , m_size(cropRect.size())
+    , m_cropRect(cropRect)
+    , m_derivedFromCanvas(1)
+    , m_bitmapSize(cropRect.size())
 {
-    IntSize canvasSize = canvas->size();
-    IntRect srcRect = intersection(cropRect, IntRect(IntPoint(), canvasSize));
-    IntRect dstRect(IntPoint(), srcRect.size());
-
-    m_buffer = ImageBuffer::create(canvasSize);
-    m_buffer->context()->drawImageBuffer(canvas->buffer(), dstRect, srcRect);
-    m_bitmap = static_cast<BitmapImage*>(m_buffer->copyImage(DontCopyBackingStore).get());
+    m_bitmap = canvas->buffer()->imageSnapshot();
 
     ScriptWrappable::init(this);
 }
 
 ImageBitmap::ImageBitmap(ImageData* data, IntRect cropRect)
     : m_bitmapOffset(max(0, -cropRect.x()), max(0, -cropRect.y()))
-    , m_size(cropRect.size())
+    , m_cropRect(cropRect)
+    , m_derivedFromCanvas(0)
 {
     IntRect srcRect = intersection(cropRect, IntRect(IntPoint(), data->size()));
 
     m_buffer = ImageBuffer::create(data->size());
     if (srcRect.width() > 0 && srcRect.height() > 0)
         m_buffer->putByteArray(Unmultiplied, data->data(), data->size(), srcRect, IntPoint(min(0, -cropRect.x()), min(0, -cropRect.y())));
 
-    m_bitmap = static_cast<BitmapImage*>(m_buffer->copyImage(DontCopyBackingStore).get());
+    m_bitmap = m_buffer->copyImage(DontCopyBackingStore);
+    m_bitmapSize = IntSize(m_bitmap->size());
 
     ScriptWrappable::init(this);
 }
 
 ImageBitmap::ImageBitmap(ImageBitmap* bitmap, IntRect cropRect)
     : m_bitmapOffset(max(0, bitmap->bitmapOffset().x() - cropRect.x()), max(0, bitmap->bitmapOffset().y() - cropRect.y()))
-    , m_size(cropRect.size())
+    , m_cropRect(cropRect)
+    , m_derivedFromCanvas(0)
 {
-    Image* bitmapImage = bitmap->bitmapImage();
+    Image* bitmapImage = bitmap->bitmapImage().get();
     cropRect.moveBy(IntPoint(-bitmap->bitmapOffset().x(), -bitmap->bitmapOffset().y()));
-    m_bitmap = cropImage(bitmapImage, cropRect).get();
+    m_bitmap = cropImage(bitmapImage, cropRect);
+    m_bitmapSize = IntSize(m_bitmap->size());
 
     ScriptWrappable::init(this);
 }
 
 PassRefPtr<ImageBitmap> ImageBitmap::create(HTMLImageElement* image, IntRect cropRect)
 {
     IntRect normalizedCropRect = normalizeRect(cropRect);
     RefPtr<ImageBitmap> imageBitmap(adoptRef(new ImageBitmap(image, normalizedCropRect)));
     return imageBitmap.release();
 }
@@ skipping 20 matching lines @@
 }
 
 PassRefPtr<ImageBitmap> ImageBitmap::create(ImageBitmap* bitmap, IntRect cropRect)
 {
     IntRect normalizedCropRect = normalizeRect(cropRect);
     RefPtr<ImageBitmap> imageBitmap(adoptRef(new ImageBitmap(bitmap, normalizedCropRect)));
     return imageBitmap.release();
 }
 
 }