1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
|
/*
* Copyright (C) 2006 Apple Computer, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef GIFImageDecoder_h
#define GIFImageDecoder_h
#include "ImageDecoder.h"
#include <wtf/OwnPtr.h>
class GIFImageReader;
namespace WebCore {
// This class decodes the GIF image format.
class GIFImageDecoder : public ImageDecoder {
public:
GIFImageDecoder();
virtual ~GIFImageDecoder();
enum GIFQuery { GIFFullQuery, GIFSizeQuery, GIFFrameCountQuery };
// ImageDecoder
virtual String filenameExtension() const { return "gif"; }
virtual void setData(SharedBuffer* data, bool allDataReceived);
virtual bool isSizeAvailable();
virtual bool setSize(unsigned width, unsigned height);
virtual size_t frameCount();
virtual int repetitionCount() const;
virtual RGBA32Buffer* frameBufferAtIndex(size_t index);
// CAUTION: setFailed() deletes |m_reader|. Be careful to avoid
// accessing deleted memory, especially when calling this from inside
// GIFImageReader!
virtual bool setFailed();
virtual void clearFrameBufferCache(size_t clearBeforeFrame);
// Callbacks from the GIF reader.
void decodingHalted(unsigned bytesLeft);
bool haveDecodedRow(unsigned frameIndex, unsigned char* rowBuffer, unsigned char* rowEnd, unsigned rowNumber, unsigned repeatCount, bool writeTransparentPixels);
bool frameComplete(unsigned frameIndex, unsigned frameDuration, RGBA32Buffer::FrameDisposalMethod disposalMethod);
void gifComplete();
private:
// If the query is GIFFullQuery, decodes the image up to (but not
// including) |haltAtFrame|. Otherwise, decodes as much as is needed to
// answer the query, ignoring bitmap data. If decoding fails but there
// is no more data coming, sets the "decode failure" flag.
void decode(unsigned haltAtFrame, GIFQuery);
// Called to initialize the frame buffer with the given index, based on
// the previous frame's disposal method. Returns true on success. On
// failure, this will mark the image as failed.
bool initFrameBuffer(unsigned frameIndex);
bool m_alreadyScannedThisDataForFrameCount;
bool m_currentBufferSawAlpha;
mutable int m_repetitionCount;
OwnPtr<GIFImageReader> m_reader;
unsigned m_readOffset;
};
} // namespace WebCore
#endif
|
