src/third_party/WebKit/Source/platform/graphics/RecordingImageBufferSurface.cpp

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "config.h"
   6
   7 #include "platform/graphics/RecordingImageBufferSurface.h"
   8
   9 #include "platform/graphics/GraphicsContext.h"
  10 #include "platform/graphics/ImageBuffer.h"
  11 #include "public/platform/Platform.h"
  12 #include "third_party/skia/include/core/SkCanvas.h"
  13 #include "third_party/skia/include/core/SkPictureRecorder.h"
  14 #include "wtf/PassOwnPtr.h"
  15 #include "wtf/PassRefPtr.h"
  16
  17 namespace blink {
  18
  19 RecordingImageBufferSurface::RecordingImageBufferSurface(const IntSize& size, OpacityMode opacityMode)
  20     : ImageBufferSurface(size, opacityMode)
  21     , m_imageBuffer(0)
  22     , m_initialSaveCount(0)
  23     , m_frameWasCleared(true)
  24 {
  25     initializeCurrentFrame();
  26 }
  27
  28 RecordingImageBufferSurface::~RecordingImageBufferSurface()
  29 { }
  30
  31 void RecordingImageBufferSurface::initializeCurrentFrame()
  32 {
  33     static SkRTreeFactory rTreeFactory;
  34     m_currentFrame = adoptPtr(new SkPictureRecorder);
  35     m_currentFrame->beginRecording(size().width(), size().height(), &rTreeFactory);
  36     m_initialSaveCount = m_currentFrame->getRecordingCanvas()->getSaveCount();
  37     if (m_imageBuffer) {
  38         m_imageBuffer->context()->resetCanvas(m_currentFrame->getRecordingCanvas());
  39         m_imageBuffer->context()->setRegionTrackingMode(GraphicsContext::RegionTrackingOverwrite);
  40     }
  41 }
  42
  43 void RecordingImageBufferSurface::setImageBuffer(ImageBuffer* imageBuffer)
  44 {
  45     m_imageBuffer = imageBuffer;
  46     if (m_currentFrame && m_imageBuffer) {
  47         m_imageBuffer->context()->setRegionTrackingMode(GraphicsContext::RegionTrackingOverwrite);
  48         m_imageBuffer->context()->resetCanvas(m_currentFrame->getRecordingCanvas());
  49     }
  50 }
  51
  52 void RecordingImageBufferSurface::willAccessPixels()
  53 {
  54     fallBackToRasterCanvas();
  55 }
  56
  57 void RecordingImageBufferSurface::fallBackToRasterCanvas()
  58 {
  59     if (m_rasterCanvas) {
  60         ASSERT(!m_currentFrame);
  61         return;
  62     }
  63
  64     m_rasterCanvas = adoptPtr(SkCanvas::NewRasterN32(size().width(), size().height()));
  65
  66     if (m_previousFrame) {
  67         m_previousFrame->draw(m_rasterCanvas.get());
  68         m_previousFrame.clear();
  69     }
  70     if (m_currentFrame) {
  71         RefPtr<SkPicture> currentPicture = adoptRef(m_currentFrame->endRecording());
  72         currentPicture->draw(m_rasterCanvas.get());
  73         m_currentFrame.clear();
  74     }
  75
  76     if (m_imageBuffer) {
  77         m_imageBuffer->context()->setRegionTrackingMode(GraphicsContext::RegionTrackingDisabled);
  78         m_imageBuffer->context()->resetCanvas(m_rasterCanvas.get());
  79     }
  80 }
  81
  82 SkCanvas* RecordingImageBufferSurface::canvas() const
  83 {
  84     if (m_rasterCanvas)
  85         return m_rasterCanvas.get();
  86
  87     ASSERT(m_currentFrame->getRecordingCanvas());
  88     return m_currentFrame->getRecordingCanvas();
  89 }
  90
  91 PassRefPtr<SkPicture> RecordingImageBufferSurface::getPicture()
  92 {
  93     bool canUsePicture = finalizeFrameInternal();
  94     m_imageBuffer->didFinalizeFrame();
  95
  96     if (canUsePicture) {
  97         return m_previousFrame;
  98     }
  99
 100     if (!m_rasterCanvas)
 101         fallBackToRasterCanvas();
 102     return nullptr;
 103 }
 104
 105 void RecordingImageBufferSurface::finalizeFrame()
 106 {
 107     if (!finalizeFrameInternal() && !m_rasterCanvas) {
 108         fallBackToRasterCanvas();
 109     }
 110 }
 111
 112 void RecordingImageBufferSurface::didClearCanvas()
 113 {
 114     m_frameWasCleared = true;
 115 }
 116
 117 bool RecordingImageBufferSurface::finalizeFrameInternal()
 118 {
 119     if (!m_imageBuffer->isDirty()) {
 120         if (m_currentFrame && !m_previousFrame) {
 121             // Create an initial blank frame
 122             m_previousFrame = adoptRef(m_currentFrame->endRecording());
 123             initializeCurrentFrame();
 124         }
 125         return m_currentFrame;
 126     }
 127
 128     if (!m_currentFrame) {
 129         return false;
 130     }
 131
 132     IntRect canvasRect(IntPoint(0, 0), size());
 133     if (!m_frameWasCleared && !m_imageBuffer->context()->opaqueRegion().asRect().contains(canvasRect)) {
 134         return false;
 135     }
 136
 137     SkCanvas* oldCanvas = m_currentFrame->getRecordingCanvas(); // Could be raster or picture
 138
 139     // FIXME(crbug.com/392614): handle transferring complex state from the current picture to the new one.
 140     if (oldCanvas->getSaveCount() > m_initialSaveCount)
 141         return false;
 142
 143     if (!oldCanvas->isClipRect())
 144         return false;
 145
 146     SkMatrix ctm = oldCanvas->getTotalMatrix();
 147     SkRect clip;
 148     oldCanvas->getClipBounds(&clip);
 149
 150     m_previousFrame = adoptRef(m_currentFrame->endRecording());
 151     initializeCurrentFrame();
 152
 153     SkCanvas* newCanvas = m_currentFrame->getRecordingCanvas();
 154     newCanvas->concat(ctm);
 155     newCanvas->clipRect(clip);
 156
 157     m_frameWasCleared = false;
 158     return true;
 159 }
 160
 161 } // namespace blink