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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/html/HTMLElement.h"
32 #include "core/html/canvas/CanvasImageSource.h"
33 #include "platform/geometry/FloatRect.h"
34 #include "platform/geometry/IntSize.h"
35 #include "platform/graphics/Canvas2DLayerBridge.h"
36 #include "platform/graphics/GraphicsTypes.h"
37 #include "platform/graphics/ImageBufferClient.h"
38 #include "platform/heap/Handle.h"
39 #include "wtf/Forward.h"
41 #define CanvasDefaultInterpolationQuality InterpolationLow
45 class AffineTransform;
46 class CanvasContextAttributes;
47 class CanvasRenderingContext;
48 class GraphicsContext;
49 class GraphicsContextStateSaver;
50 class HTMLCanvasElement;
54 class ImageBufferSurface;
57 class CanvasObserver {
59 virtual ~CanvasObserver() { }
61 virtual void canvasChanged(HTMLCanvasElement*, const FloatRect& changedRect) = 0;
62 virtual void canvasResized(HTMLCanvasElement*) = 0;
63 virtual void canvasDestroyed(HTMLCanvasElement*) = 0;
66 class HTMLCanvasElement FINAL : public HTMLElement, public DocumentVisibilityObserver, public CanvasImageSource, public ImageBufferClient {
67 WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(HTMLCanvasElement);
69 static PassRefPtrWillBeRawPtr<HTMLCanvasElement> create(Document&);
70 virtual ~HTMLCanvasElement();
72 void addObserver(CanvasObserver*);
73 void removeObserver(CanvasObserver*);
75 // Attributes and functions exposed to script
76 int width() const { return size().width(); }
77 int height() const { return size().height(); }
79 const IntSize& size() const { return m_size; }
83 void setAccelerationDisabled(bool accelerationDisabled) { m_accelerationDisabled = accelerationDisabled; }
84 bool accelerationDisabled() const { return m_accelerationDisabled; }
86 void setSize(const IntSize& newSize)
88 if (newSize == size())
91 setWidth(newSize.width());
92 setHeight(newSize.height());
93 m_ignoreReset = false;
97 CanvasRenderingContext* getContext(const String&, CanvasContextAttributes* attributes = 0);
99 static String toEncodingMimeType(const String& mimeType);
100 String toDataURL(const String& mimeType, const double* quality, ExceptionState&) const;
101 String toDataURL(const String& mimeType, ExceptionState& exceptionState) const { return toDataURL(mimeType, 0, exceptionState); }
103 // Used for rendering
104 void didDraw(const FloatRect&);
105 void notifyObserversCanvasChanged(const FloatRect&);
107 void paint(GraphicsContext*, const LayoutRect&);
109 GraphicsContext* drawingContext() const;
110 GraphicsContext* existingDrawingContext() const;
112 CanvasRenderingContext* renderingContext() const { return m_context.get(); }
114 void ensureUnacceleratedImageBuffer();
115 ImageBuffer* buffer() const;
116 Image* copiedImage() const;
117 void clearCopiedImage();
118 PassRefPtrWillBeRawPtr<ImageData> getImageData() const;
119 void makePresentationCopy();
120 void clearPresentationCopy();
122 SecurityOrigin* securityOrigin() const;
123 bool originClean() const { return m_originClean; }
124 void setOriginTainted() { m_originClean = false; }
126 AffineTransform baseTransform() const;
130 bool hasImageBuffer() const { return m_imageBuffer; }
131 bool hasValidImageBuffer() const;
132 void discardImageBuffer();
134 bool shouldAccelerate(const IntSize&) const;
136 virtual const AtomicString imageSourceURL() const OVERRIDE;
138 virtual InsertionNotificationRequest insertedInto(ContainerNode*) OVERRIDE;
140 // DocumentVisibilityObserver implementation
141 virtual void didChangeVisibilityState(PageVisibilityState) OVERRIDE;
143 // CanvasImageSource implementation
144 virtual PassRefPtr<Image> getSourceImageForCanvas(SourceImageMode, SourceImageStatus*) const OVERRIDE;
145 virtual bool wouldTaintOrigin(SecurityOrigin*) const OVERRIDE;
146 virtual FloatSize sourceSize() const OVERRIDE;
148 // ImageBufferClient implementation
149 virtual void notifySurfaceInvalid() OVERRIDE;
151 virtual void trace(Visitor*) OVERRIDE;
154 virtual void didMoveToNewDocument(Document& oldDocument) OVERRIDE;
157 explicit HTMLCanvasElement(Document&);
159 virtual void parseAttribute(const QualifiedName&, const AtomicString&) OVERRIDE;
160 virtual RenderObject* createRenderer(RenderStyle*) OVERRIDE;
161 virtual bool areAuthorShadowsAllowed() const OVERRIDE { return false; }
165 PassOwnPtr<ImageBufferSurface> createImageBufferSurface(const IntSize& deviceSize, int* msaaSampleCount);
166 void createImageBuffer();
167 void createImageBufferInternal();
168 void clearImageBuffer();
170 void setSurfaceSize(const IntSize&);
172 bool paintsIntoCanvasBuffer() const;
174 void updateExternallyAllocatedMemory() const;
176 String toDataURLInternal(const String& mimeType, const double* quality) const;
178 HashSet<CanvasObserver*> m_observers;
182 OwnPtrWillBeMember<CanvasRenderingContext> m_context;
185 bool m_accelerationDisabled;
186 FloatRect m_dirtyRect;
188 mutable intptr_t m_externallyAllocatedMemory;
192 // It prevents HTMLCanvasElement::buffer() from continuously re-attempting to allocate an imageBuffer
193 // after the first attempt failed.
194 mutable bool m_didFailToCreateImageBuffer;
195 mutable bool m_didClearImageBuffer;
196 OwnPtr<ImageBuffer> m_imageBuffer;
197 mutable OwnPtr<GraphicsContextStateSaver> m_contextStateSaver;
199 mutable RefPtr<Image> m_presentedImage;
200 mutable RefPtr<Image> m_copiedImage; // FIXME: This is temporary for platforms that have to copy the image buffer to render (and for CSSCanvasValue).