2 * Copyright (C) 2004, 2006, 2009, 2010 Apple Inc. All rights reserved.
3 * Copyright (C) 2007 Alp Toker <alp@atoker.com>
4 * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
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28 #ifndef HTMLCanvasElement_h
29 #define HTMLCanvasElement_h
31 #include "core/dom/Document.h"
32 #include "core/html/HTMLElement.h"
33 #include "core/html/canvas/CanvasImageSource.h"
34 #include "platform/geometry/FloatRect.h"
35 #include "platform/geometry/IntSize.h"
36 #include "platform/graphics/Canvas2DLayerBridge.h"
37 #include "platform/graphics/GraphicsTypes.h"
38 #include "platform/graphics/ImageBufferClient.h"
39 #include "platform/heap/Handle.h"
40 #include "public/platform/WebThread.h"
41 #include "wtf/Forward.h"
43 #define CanvasDefaultInterpolationQuality InterpolationLow
47 class AffineTransform;
48 class CanvasContextAttributes;
49 class CanvasRenderingContext;
50 class GraphicsContext;
51 class GraphicsContextStateSaver;
52 class HTMLCanvasElement;
56 class ImageBufferSurface;
58 class RecordingImageBufferFallbackSurfaceFactory;
60 class CanvasObserver : public WillBeGarbageCollectedMixin {
61 DECLARE_EMPTY_VIRTUAL_DESTRUCTOR_WILL_BE_REMOVED(CanvasObserver);
63 virtual void canvasChanged(HTMLCanvasElement*, const FloatRect& changedRect) = 0;
64 virtual void canvasResized(HTMLCanvasElement*) = 0;
66 virtual void canvasDestroyed(HTMLCanvasElement*) = 0;
69 virtual void trace(Visitor*) { }
72 class HTMLCanvasElement final : public HTMLElement, public DocumentVisibilityObserver, public CanvasImageSource, public ImageBufferClient, public blink::WebThread::TaskObserver {
73 DEFINE_WRAPPERTYPEINFO();
74 WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(HTMLCanvasElement);
76 DECLARE_NODE_FACTORY(HTMLCanvasElement);
77 virtual ~HTMLCanvasElement();
79 void addObserver(CanvasObserver*);
80 void removeObserver(CanvasObserver*);
82 // Attributes and functions exposed to script
83 int width() const { return size().width(); }
84 int height() const { return size().height(); }
86 const IntSize& size() const { return m_size; }
90 void setAccelerationDisabled(bool accelerationDisabled) { m_accelerationDisabled = accelerationDisabled; }
91 bool accelerationDisabled() const { return m_accelerationDisabled; }
93 void setSize(const IntSize& newSize)
95 if (newSize == size())
98 setWidth(newSize.width());
99 setHeight(newSize.height());
100 m_ignoreReset = false;
104 CanvasRenderingContext* getContext(const String&, CanvasContextAttributes* attributes = 0);
106 static String toEncodingMimeType(const String& mimeType);
107 String toDataURL(const String& mimeType, const double* quality, ExceptionState&) const;
108 String toDataURL(const String& mimeType, ExceptionState& exceptionState) const { return toDataURL(mimeType, 0, exceptionState); }
110 // Used for rendering
111 void didDraw(const FloatRect&);
112 void notifyObserversCanvasChanged(const FloatRect&);
114 void paint(GraphicsContext*, const LayoutRect&);
116 GraphicsContext* drawingContext() const;
117 GraphicsContext* existingDrawingContext() const;
119 CanvasRenderingContext* renderingContext() const { return m_context.get(); }
121 void ensureUnacceleratedImageBuffer();
122 ImageBuffer* buffer() const;
123 Image* copiedImage() const;
124 void clearCopiedImage();
125 PassRefPtrWillBeRawPtr<ImageData> getImageData() const;
126 void makePresentationCopy();
127 void clearPresentationCopy();
129 SecurityOrigin* securityOrigin() const;
130 bool originClean() const { return m_originClean; }
131 void setOriginTainted() { m_originClean = false; }
133 AffineTransform baseTransform() const;
137 bool hasImageBuffer() const { return m_imageBuffer; }
138 bool hasValidImageBuffer() const;
139 void discardImageBuffer();
141 bool shouldAccelerate(const IntSize&) const;
143 virtual const AtomicString imageSourceURL() const override;
145 virtual InsertionNotificationRequest insertedInto(ContainerNode*) override;
147 // DocumentVisibilityObserver implementation
148 virtual void didChangeVisibilityState(PageVisibilityState) override;
150 // CanvasImageSource implementation
151 virtual PassRefPtr<Image> getSourceImageForCanvas(SourceImageMode, SourceImageStatus*) const override;
152 virtual bool wouldTaintOrigin(SecurityOrigin*) const override;
153 virtual FloatSize sourceSize() const override;
155 // ImageBufferClient implementation
156 virtual void notifySurfaceInvalid() override;
157 virtual bool isDirty() override { return !m_dirtyRect.isEmpty(); }
158 virtual void didFinalizeFrame() override;
160 // Implementation of WebThread::TaskObserver methods
161 virtual void willProcessTask() override;
162 virtual void didProcessTask() override;
164 virtual void trace(Visitor*) override;
167 virtual void didMoveToNewDocument(Document& oldDocument) override;
170 explicit HTMLCanvasElement(Document&);
172 virtual void parseAttribute(const QualifiedName&, const AtomicString&) override;
173 virtual RenderObject* createRenderer(RenderStyle*) override;
174 virtual bool areAuthorShadowsAllowed() const override { return false; }
178 PassOwnPtr<RecordingImageBufferFallbackSurfaceFactory> createSurfaceFactory(const IntSize& deviceSize, int* msaaSampleCount) const;
179 PassOwnPtr<ImageBufferSurface> createImageBufferSurface(const IntSize& deviceSize, int* msaaSampleCount);
180 void createImageBuffer();
181 void createImageBufferInternal();
182 void clearImageBuffer();
183 bool shouldUseDisplayList(const IntSize& deviceSize);
185 void resetDirtyRect();
187 void setSurfaceSize(const IntSize&);
189 bool paintsIntoCanvasBuffer() const;
191 void updateExternallyAllocatedMemory() const;
193 String toDataURLInternal(const String& mimeType, const double* quality, bool isSaving = false) const;
195 WillBeHeapHashSet<RawPtrWillBeWeakMember<CanvasObserver>> m_observers;
199 OwnPtrWillBeMember<CanvasRenderingContext> m_context;
202 bool m_accelerationDisabled;
203 FloatRect m_dirtyRect;
205 mutable intptr_t m_externallyAllocatedMemory;
209 // It prevents HTMLCanvasElement::buffer() from continuously re-attempting to allocate an imageBuffer
210 // after the first attempt failed.
211 mutable bool m_didFailToCreateImageBuffer;
212 mutable bool m_didClearImageBuffer;
213 OwnPtr<ImageBuffer> m_imageBuffer;
214 mutable OwnPtr<GraphicsContextStateSaver> m_contextStateSaver;
216 mutable RefPtr<Image> m_presentedImage;
217 mutable RefPtr<Image> m_copiedImage; // FIXME: This is temporary for platforms that have to copy the image buffer to render (and for CSSCanvasValue).
222 #endif // HTMLCanvasElement_h