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 "wtf/Forward.h"
42 #define CanvasDefaultInterpolationQuality InterpolationLow
46 class AffineTransform;
47 class CanvasContextAttributes;
48 class CanvasRenderingContext;
49 class GraphicsContext;
50 class GraphicsContextStateSaver;
51 class HTMLCanvasElement;
55 class ImageBufferSurface;
58 class CanvasObserver : public WillBeGarbageCollectedMixin {
59 DECLARE_EMPTY_VIRTUAL_DESTRUCTOR_WILL_BE_REMOVED(CanvasObserver);
61 virtual void canvasChanged(HTMLCanvasElement*, const FloatRect& changedRect) = 0;
62 virtual void canvasResized(HTMLCanvasElement*) = 0;
64 virtual void canvasDestroyed(HTMLCanvasElement*) = 0;
67 virtual void trace(Visitor*) { }
70 class HTMLCanvasElement FINAL : public HTMLElement, public DocumentVisibilityObserver, public CanvasImageSource, public ImageBufferClient {
71 WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(HTMLCanvasElement);
73 DECLARE_NODE_FACTORY(HTMLCanvasElement);
74 virtual ~HTMLCanvasElement();
76 void addObserver(CanvasObserver*);
77 void removeObserver(CanvasObserver*);
79 // Attributes and functions exposed to script
80 int width() const { return size().width(); }
81 int height() const { return size().height(); }
83 const IntSize& size() const { return m_size; }
87 void setAccelerationDisabled(bool accelerationDisabled) { m_accelerationDisabled = accelerationDisabled; }
88 bool accelerationDisabled() const { return m_accelerationDisabled; }
90 void setSize(const IntSize& newSize)
92 if (newSize == size())
95 setWidth(newSize.width());
96 setHeight(newSize.height());
97 m_ignoreReset = false;
101 CanvasRenderingContext* getContext(const String&, CanvasContextAttributes* attributes = 0);
103 static String toEncodingMimeType(const String& mimeType);
104 String toDataURL(const String& mimeType, const double* quality, ExceptionState&) const;
105 String toDataURL(const String& mimeType, ExceptionState& exceptionState) const { return toDataURL(mimeType, 0, exceptionState); }
107 // Used for rendering
108 void didDraw(const FloatRect&);
109 void notifyObserversCanvasChanged(const FloatRect&);
111 void paint(GraphicsContext*, const LayoutRect&);
113 GraphicsContext* drawingContext() const;
114 GraphicsContext* existingDrawingContext() const;
116 CanvasRenderingContext* renderingContext() const { return m_context.get(); }
118 void ensureUnacceleratedImageBuffer();
119 ImageBuffer* buffer() const;
120 Image* copiedImage() const;
121 void clearCopiedImage();
122 PassRefPtrWillBeRawPtr<ImageData> getImageData() const;
123 void makePresentationCopy();
124 void clearPresentationCopy();
126 SecurityOrigin* securityOrigin() const;
127 bool originClean() const { return m_originClean; }
128 void setOriginTainted() { m_originClean = false; }
130 AffineTransform baseTransform() const;
134 bool hasImageBuffer() const { return m_imageBuffer; }
135 bool hasValidImageBuffer() const;
136 void discardImageBuffer();
138 bool shouldAccelerate(const IntSize&) const;
140 virtual const AtomicString imageSourceURL() const OVERRIDE;
142 virtual InsertionNotificationRequest insertedInto(ContainerNode*) OVERRIDE;
144 // DocumentVisibilityObserver implementation
145 virtual void didChangeVisibilityState(PageVisibilityState) OVERRIDE;
147 // CanvasImageSource implementation
148 virtual PassRefPtr<Image> getSourceImageForCanvas(SourceImageMode, SourceImageStatus*) const OVERRIDE;
149 virtual bool wouldTaintOrigin(SecurityOrigin*) const OVERRIDE;
150 virtual FloatSize sourceSize() const OVERRIDE;
152 // ImageBufferClient implementation
153 virtual void notifySurfaceInvalid() OVERRIDE;
155 virtual void trace(Visitor*) OVERRIDE;
158 virtual void didMoveToNewDocument(Document& oldDocument) OVERRIDE;
161 explicit HTMLCanvasElement(Document&);
163 virtual void parseAttribute(const QualifiedName&, const AtomicString&) OVERRIDE;
164 virtual RenderObject* createRenderer(RenderStyle*) OVERRIDE;
165 virtual bool areAuthorShadowsAllowed() const OVERRIDE { return false; }
169 PassOwnPtr<ImageBufferSurface> createImageBufferSurface(const IntSize& deviceSize, int* msaaSampleCount);
170 void createImageBuffer();
171 void createImageBufferInternal();
172 void clearImageBuffer();
174 void setSurfaceSize(const IntSize&);
176 bool paintsIntoCanvasBuffer() const;
178 void updateExternallyAllocatedMemory() const;
180 String toDataURLInternal(const String& mimeType, const double* quality, bool isSaving = false) const;
182 WillBeHeapHashSet<RawPtrWillBeWeakMember<CanvasObserver> > m_observers;
186 OwnPtrWillBeMember<CanvasRenderingContext> m_context;
189 bool m_accelerationDisabled;
190 FloatRect m_dirtyRect;
192 mutable intptr_t m_externallyAllocatedMemory;
196 // It prevents HTMLCanvasElement::buffer() from continuously re-attempting to allocate an imageBuffer
197 // after the first attempt failed.
198 mutable bool m_didFailToCreateImageBuffer;
199 mutable bool m_didClearImageBuffer;
200 OwnPtr<ImageBuffer> m_imageBuffer;
201 mutable OwnPtr<GraphicsContextStateSaver> m_contextStateSaver;
203 mutable RefPtr<Image> m_presentedImage;
204 mutable RefPtr<Image> m_copiedImage; // FIXME: This is temporary for platforms that have to copy the image buffer to render (and for CSSCanvasValue).