1/*
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.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
16 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
19 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
22 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
23 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#ifndef HTMLCanvasElement_h
29#define HTMLCanvasElement_h
30
31#include "FloatRect.h"
32#include "HTMLElement.h"
33#include "IntSize.h"
34#include <wtf/Forward.h>
35
36#if PLATFORM(QT)
37#define DefaultInterpolationQuality InterpolationMedium
38#elif USE(CG)
39#define DefaultInterpolationQuality InterpolationLow
40#else
41#define DefaultInterpolationQuality InterpolationDefault
42#endif
43
44namespace WebCore {
45
46class CanvasContextAttributes;
47class CanvasRenderingContext;
48class GraphicsContext;
49class GraphicsContextStateSaver;
50class HTMLCanvasElement;
51class Image;
52class ImageData;
53class ImageBuffer;
54class IntSize;
55
56class CanvasObserver {
57public:
58    virtual ~CanvasObserver() { }
59
60    virtual void canvasChanged(HTMLCanvasElement*, const FloatRect& changedRect) = 0;
61    virtual void canvasResized(HTMLCanvasElement*) = 0;
62    virtual void canvasDestroyed(HTMLCanvasElement*) = 0;
63};
64
65class HTMLCanvasElement FINAL : public HTMLElement {
66public:
67    static PassRefPtr<HTMLCanvasElement> create(Document*);
68    static PassRefPtr<HTMLCanvasElement> create(const QualifiedName&, Document*);
69    virtual ~HTMLCanvasElement();
70
71    void addObserver(CanvasObserver*);
72    void removeObserver(CanvasObserver*);
73
74    // Attributes and functions exposed to script
75    int width() const { return size().width(); }
76    int height() const { return size().height(); }
77
78    const IntSize& size() const { return m_size; }
79
80    void setWidth(int);
81    void setHeight(int);
82
83    void setSize(const IntSize& newSize)
84    {
85        if (newSize == size() && targetDeviceScaleFactor() == m_deviceScaleFactor)
86            return;
87        m_ignoreReset = true;
88        setWidth(newSize.width());
89        setHeight(newSize.height());
90        m_ignoreReset = false;
91        reset();
92    }
93
94    CanvasRenderingContext* getContext(const String&, CanvasContextAttributes* attributes = 0);
95    bool supportsContext(const String&, CanvasContextAttributes* = 0);
96    static bool is2dType(const String&);
97#if ENABLE(WEBGL)
98    static bool is3dType(const String&);
99#endif
100
101    static String toEncodingMimeType(const String& mimeType);
102    String toDataURL(const String& mimeType, const double* quality, ExceptionCode&);
103    String toDataURL(const String& mimeType, ExceptionCode& ec) { return toDataURL(mimeType, 0, ec); }
104
105    // Used for rendering
106    void didDraw(const FloatRect&);
107    void notifyObserversCanvasChanged(const FloatRect&);
108
109    void paint(GraphicsContext*, const LayoutRect&, bool useLowQualityScale = false);
110
111    GraphicsContext* drawingContext() const;
112    GraphicsContext* existingDrawingContext() const;
113
114    CanvasRenderingContext* renderingContext() const { return m_context.get(); }
115
116    ImageBuffer* buffer() const;
117    Image* copiedImage() const;
118    void clearCopiedImage();
119    PassRefPtr<ImageData> getImageData();
120    void makePresentationCopy();
121    void clearPresentationCopy();
122
123    FloatRect convertLogicalToDevice(const FloatRect&) const;
124    FloatSize convertLogicalToDevice(const FloatSize&) const;
125
126    FloatSize convertDeviceToLogical(const FloatSize&) const;
127
128    SecurityOrigin* securityOrigin() const;
129    void setOriginTainted() { m_originClean = false; }
130    bool originClean() const { return m_originClean; }
131
132    AffineTransform baseTransform() const;
133
134#if ENABLE(WEBGL)
135    bool is3D() const;
136#endif
137
138    void makeRenderingResultsAvailable();
139    bool hasCreatedImageBuffer() const { return m_hasCreatedImageBuffer; }
140
141    bool shouldAccelerate(const IntSize&) const;
142
143    float deviceScaleFactor() const { return m_deviceScaleFactor; }
144
145private:
146    HTMLCanvasElement(const QualifiedName&, Document*);
147
148    virtual void parseAttribute(const QualifiedName&, const AtomicString&) OVERRIDE;
149    virtual RenderObject* createRenderer(RenderArena*, RenderStyle*);
150    virtual void attach(const AttachContext& = AttachContext()) OVERRIDE;
151    virtual bool areAuthorShadowsAllowed() const OVERRIDE;
152
153    virtual bool canContainRangeEndPoint() const OVERRIDE;
154    virtual bool canStartSelection() const OVERRIDE;
155
156    void reset();
157
158    float targetDeviceScaleFactor() const;
159
160    void createImageBuffer() const;
161    void clearImageBuffer() const;
162
163    void setSurfaceSize(const IntSize&);
164
165    bool paintsIntoCanvasBuffer() const;
166
167    HashSet<CanvasObserver*> m_observers;
168
169    IntSize m_size;
170
171    OwnPtr<CanvasRenderingContext> m_context;
172
173    bool m_rendererIsCanvas;
174
175    bool m_ignoreReset;
176    FloatRect m_dirtyRect;
177
178    float m_deviceScaleFactor;
179    bool m_originClean;
180
181    // m_createdImageBuffer means we tried to malloc the buffer.  We didn't necessarily get it.
182    mutable bool m_hasCreatedImageBuffer;
183    mutable bool m_didClearImageBuffer;
184    mutable OwnPtr<ImageBuffer> m_imageBuffer;
185    mutable OwnPtr<GraphicsContextStateSaver> m_contextStateSaver;
186
187    mutable RefPtr<Image> m_presentedImage;
188    mutable RefPtr<Image> m_copiedImage; // FIXME: This is temporary for platforms that have to copy the image buffer to render (and for CSSCanvasValue).
189};
190
191} //namespace
192
193#endif
194