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 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 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 <memory>
35#include <wtf/Forward.h>
36
37#if USE(CG)
38#define DefaultInterpolationQuality InterpolationLow
39#else
40#define DefaultInterpolationQuality InterpolationDefault
41#endif
42
43namespace WebCore {
44
45class CanvasContextAttributes;
46class CanvasRenderingContext;
47class GraphicsContext;
48class GraphicsContextStateSaver;
49class HTMLCanvasElement;
50class Image;
51class ImageData;
52class ImageBuffer;
53class IntSize;
54
55class CanvasObserver {
56public:
57    virtual ~CanvasObserver() { }
58
59    virtual void canvasChanged(HTMLCanvasElement&, const FloatRect& changedRect) = 0;
60    virtual void canvasResized(HTMLCanvasElement&) = 0;
61    virtual void canvasDestroyed(HTMLCanvasElement&) = 0;
62};
63
64class HTMLCanvasElement final : public HTMLElement {
65public:
66    static PassRefPtr<HTMLCanvasElement> create(Document&);
67    static PassRefPtr<HTMLCanvasElement> create(const QualifiedName&, Document&);
68    virtual ~HTMLCanvasElement();
69
70    void addObserver(CanvasObserver&);
71    void removeObserver(CanvasObserver&);
72
73    // Attributes and functions exposed to script
74    int width() const { return size().width(); }
75    int height() const { return size().height(); }
76
77    const IntSize& size() const { return m_size; }
78
79    void setWidth(int);
80    void setHeight(int);
81
82    void setSize(const IntSize& newSize)
83    {
84        if (newSize == size() && targetDeviceScaleFactor() == m_deviceScaleFactor)
85            return;
86        m_ignoreReset = true;
87        setWidth(newSize.width());
88        setHeight(newSize.height());
89        m_ignoreReset = false;
90        reset();
91    }
92
93    CanvasRenderingContext* getContext(const String&, CanvasContextAttributes* attributes = 0);
94    bool probablySupportsContext(const String&, CanvasContextAttributes* = 0);
95    static bool is2dType(const String&);
96#if ENABLE(WEBGL)
97    static bool is3dType(const String&);
98#endif
99
100    static String toEncodingMimeType(const String& mimeType);
101    String toDataURL(const String& mimeType, const double* quality, ExceptionCode&);
102    String toDataURL(const String& mimeType, ExceptionCode& ec) { return toDataURL(mimeType, 0, ec); }
103
104    // Used for rendering
105    void didDraw(const FloatRect&);
106    void notifyObserversCanvasChanged(const FloatRect&);
107
108    void paint(GraphicsContext*, const LayoutRect&, bool useLowQualityScale = false);
109
110    GraphicsContext* drawingContext() const;
111    GraphicsContext* existingDrawingContext() const;
112
113    CanvasRenderingContext* renderingContext() const { return m_context.get(); }
114
115    ImageBuffer* buffer() const;
116    Image* copiedImage() const;
117    void clearCopiedImage();
118    PassRefPtr<ImageData> getImageData();
119    void makePresentationCopy();
120    void clearPresentationCopy();
121
122    FloatRect convertLogicalToDevice(const FloatRect&) const;
123    FloatSize convertLogicalToDevice(const FloatSize&) const;
124
125    FloatSize convertDeviceToLogical(const FloatSize&) const;
126
127    SecurityOrigin* securityOrigin() const;
128    void setOriginTainted() { m_originClean = false; }
129    bool originClean() const { return m_originClean; }
130
131    AffineTransform baseTransform() const;
132
133    void makeRenderingResultsAvailable();
134    bool hasCreatedImageBuffer() const { return m_hasCreatedImageBuffer; }
135
136    bool shouldAccelerate(const IntSize&) const;
137
138    float deviceScaleFactor() const { return m_deviceScaleFactor; }
139
140private:
141    HTMLCanvasElement(const QualifiedName&, Document&);
142
143    virtual void parseAttribute(const QualifiedName&, const AtomicString&) override;
144    virtual RenderPtr<RenderElement> createElementRenderer(PassRef<RenderStyle>) override;
145    virtual void willAttachRenderers() override;
146
147    virtual bool canContainRangeEndPoint() const override;
148    virtual bool canStartSelection() const override;
149
150    void reset();
151
152    float targetDeviceScaleFactor() const;
153
154    void createImageBuffer() const;
155    void clearImageBuffer() const;
156
157    void setSurfaceSize(const IntSize&);
158
159    bool paintsIntoCanvasBuffer() const;
160
161#if ENABLE(WEBGL)
162    bool is3D() const;
163#endif
164
165    HashSet<CanvasObserver*> m_observers;
166
167    IntSize m_size;
168
169    std::unique_ptr<CanvasRenderingContext> m_context;
170
171    bool m_rendererIsCanvas;
172
173    bool m_ignoreReset;
174    FloatRect m_dirtyRect;
175
176    float m_deviceScaleFactor;
177    bool m_originClean;
178
179    // m_createdImageBuffer means we tried to malloc the buffer.  We didn't necessarily get it.
180    mutable bool m_hasCreatedImageBuffer;
181    mutable bool m_didClearImageBuffer;
182    mutable std::unique_ptr<ImageBuffer> m_imageBuffer;
183    mutable std::unique_ptr<GraphicsContextStateSaver> m_contextStateSaver;
184
185    mutable RefPtr<Image> m_presentedImage;
186    mutable RefPtr<Image> m_copiedImage; // FIXME: This is temporary for platforms that have to copy the image buffer to render (and for CSSCanvasValue).
187};
188
189NODE_TYPE_CASTS(HTMLCanvasElement)
190
191} //namespace
192
193#endif
194