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;
59 class CanvasObserver : public WillBeGarbageCollectedMixin {
60 DECLARE_EMPTY_VIRTUAL_DESTRUCTOR_WILL_BE_REMOVED(CanvasObserver);
62 virtual void canvasChanged(HTMLCanvasElement*, const FloatRect& changedRect) = 0;
63 virtual void canvasResized(HTMLCanvasElement*) = 0;
65 virtual void canvasDestroyed(HTMLCanvasElement*) = 0;
68 virtual void trace(Visitor*) { }
71 class HTMLCanvasElement FINAL : public HTMLElement, public DocumentVisibilityObserver, public CanvasImageSource, public ImageBufferClient, public blink::WebThread::TaskObserver {
72 DEFINE_WRAPPERTYPEINFO();
73 WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(HTMLCanvasElement);
75 DECLARE_NODE_FACTORY(HTMLCanvasElement);
76 virtual ~HTMLCanvasElement();
78 void addObserver(CanvasObserver*);
79 void removeObserver(CanvasObserver*);
81 // Attributes and functions exposed to script
82 int width() const { return size().width(); }
83 int height() const { return size().height(); }
85 const IntSize& size() const { return m_size; }
89 void setAccelerationDisabled(bool accelerationDisabled) { m_accelerationDisabled = accelerationDisabled; }
90 bool accelerationDisabled() const { return m_accelerationDisabled; }
92 void setSize(const IntSize& newSize)
94 if (newSize == size())
97 setWidth(newSize.width());
98 setHeight(newSize.height());
99 m_ignoreReset = false;
103 CanvasRenderingContext* getContext(const String&, CanvasContextAttributes* attributes = 0);
105 static String toEncodingMimeType(const String& mimeType);
106 String toDataURL(const String& mimeType, const double* quality, ExceptionState&) const;
107 String toDataURL(const String& mimeType, ExceptionState& exceptionState) const { return toDataURL(mimeType, 0, exceptionState); }
109 // Used for rendering
110 void didDraw(const FloatRect&);
111 void notifyObserversCanvasChanged(const FloatRect&);
113 void paint(GraphicsContext*, const LayoutRect&);
115 GraphicsContext* drawingContext() const;
116 GraphicsContext* existingDrawingContext() const;
118 CanvasRenderingContext* renderingContext() const { return m_context.get(); }
120 void ensureUnacceleratedImageBuffer();
121 ImageBuffer* buffer() const;
122 Image* copiedImage() const;
123 void clearCopiedImage();
124 PassRefPtrWillBeRawPtr<ImageData> getImageData() const;
125 void makePresentationCopy();
126 void clearPresentationCopy();
128 SecurityOrigin* securityOrigin() const;
129 bool originClean() const { return m_originClean; }
130 void setOriginTainted() { m_originClean = false; }
132 AffineTransform baseTransform() const;
136 bool hasImageBuffer() const { return m_imageBuffer; }
137 bool hasValidImageBuffer() const;
138 void discardImageBuffer();
140 bool shouldAccelerate(const IntSize&) const;
142 virtual const AtomicString imageSourceURL() const OVERRIDE;
144 virtual InsertionNotificationRequest insertedInto(ContainerNode*) OVERRIDE;
146 // DocumentVisibilityObserver implementation
147 virtual void didChangeVisibilityState(PageVisibilityState) OVERRIDE;
149 // CanvasImageSource implementation
150 virtual PassRefPtr<Image> getSourceImageForCanvas(SourceImageMode, SourceImageStatus*) const OVERRIDE;
151 virtual bool wouldTaintOrigin(SecurityOrigin*) const OVERRIDE;
152 virtual FloatSize sourceSize() const OVERRIDE;
154 // ImageBufferClient implementation
155 virtual void notifySurfaceInvalid() OVERRIDE;
156 virtual bool isDirty() OVERRIDE { return !m_dirtyRect.isEmpty(); }
157 virtual void didFinalizeFrame() OVERRIDE;
159 // Implementation of WebThread::TaskObserver methods
160 virtual void willProcessTask() OVERRIDE;
161 virtual void didProcessTask() OVERRIDE;
163 virtual void trace(Visitor*) OVERRIDE;
166 virtual void didMoveToNewDocument(Document& oldDocument) OVERRIDE;
169 explicit HTMLCanvasElement(Document&);
171 virtual void parseAttribute(const QualifiedName&, const AtomicString&) OVERRIDE;
172 virtual RenderObject* createRenderer(RenderStyle*) OVERRIDE;
173 virtual bool areAuthorShadowsAllowed() const OVERRIDE { return false; }
177 PassOwnPtr<ImageBufferSurface> createImageBufferSurface(const IntSize& deviceSize, int* msaaSampleCount);
178 void createImageBuffer();
179 void createImageBufferInternal();
180 void clearImageBuffer();
182 void resetDirtyRect();
184 void setSurfaceSize(const IntSize&);
186 bool paintsIntoCanvasBuffer() const;
188 void updateExternallyAllocatedMemory() const;
190 String toDataURLInternal(const String& mimeType, const double* quality, bool isSaving = false) const;
192 WillBeHeapHashSet<RawPtrWillBeWeakMember<CanvasObserver> > m_observers;
196 OwnPtrWillBeMember<CanvasRenderingContext> m_context;
199 bool m_accelerationDisabled;
200 FloatRect m_dirtyRect;
202 mutable intptr_t m_externallyAllocatedMemory;
206 // It prevents HTMLCanvasElement::buffer() from continuously re-attempting to allocate an imageBuffer
207 // after the first attempt failed.
208 mutable bool m_didFailToCreateImageBuffer;
209 mutable bool m_didClearImageBuffer;
210 OwnPtr<ImageBuffer> m_imageBuffer;
211 mutable OwnPtr<GraphicsContextStateSaver> m_contextStateSaver;
213 mutable RefPtr<Image> m_presentedImage;
214 mutable RefPtr<Image> m_copiedImage; // FIXME: This is temporary for platforms that have to copy the image buffer to render (and for CSSCanvasValue).
219 #endif // HTMLCanvasElement_h