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1 /* | 1 /* |
2 * Copyright (C) 2006 Apple Computer, Inc. All rights reserved. | 2 * Copyright (C) 2006 Apple Computer, Inc. All rights reserved. |
3 * | 3 * |
4 * Redistribution and use in source and binary forms, with or without | 4 * Redistribution and use in source and binary forms, with or without |
5 * modification, are permitted provided that the following conditions | 5 * modification, are permitted provided that the following conditions |
6 * are met: | 6 * are met: |
7 * 1. Redistributions of source code must retain the above copyright | 7 * 1. Redistributions of source code must retain the above copyright |
8 * notice, this list of conditions and the following disclaimer. | 8 * notice, this list of conditions and the following disclaimer. |
9 * 2. Redistributions in binary form must reproduce the above copyright | 9 * 2. Redistributions in binary form must reproduce the above copyright |
10 * notice, this list of conditions and the following disclaimer in the | 10 * notice, this list of conditions and the following disclaimer in the |
(...skipping 25 matching lines...) Expand all Loading... | |
36 class PLATFORM_EXPORT PNGImageDecoder final : public ImageDecoder { | 36 class PLATFORM_EXPORT PNGImageDecoder final : public ImageDecoder { |
37 WTF_MAKE_NONCOPYABLE(PNGImageDecoder); | 37 WTF_MAKE_NONCOPYABLE(PNGImageDecoder); |
38 | 38 |
39 public: | 39 public: |
40 PNGImageDecoder(AlphaOption, | 40 PNGImageDecoder(AlphaOption, |
41 ColorSpaceOption, | 41 ColorSpaceOption, |
42 size_t maxDecodedBytes, | 42 size_t maxDecodedBytes, |
43 size_t offset = 0); | 43 size_t offset = 0); |
44 ~PNGImageDecoder() override; | 44 ~PNGImageDecoder() override; |
45 | 45 |
46 enum class PNGParseQuery { PNGSizeQuery, PNGMetaDataQuery }; | |
47 | |
46 // ImageDecoder: | 48 // ImageDecoder: |
47 String filenameExtension() const override { return "png"; } | 49 String filenameExtension() const override { return "png"; } |
50 int repetitionCount() const override; | |
51 bool frameIsCompleteAtIndex(size_t) const override; | |
52 float frameDurationAtIndex(size_t) const override; | |
53 size_t clearCacheExceptFrame(size_t) override; | |
54 // Failures are handled differently, based on the image and state of the | |
55 // decoder: | |
56 // | |
57 // 1) When a non-animated PNG, or the first frame of an animated PNG, can't | |
scroggo_chromium
2016/11/29 16:30:52
nit: these commas are unnecessary
joostouwerling
2016/12/02 16:08:42
Done.
| |
58 // be decoded or parsed, set the decoder to the failed state, because there | |
59 // are no frames we can show to the client. Also set the state to failed if | |
scroggo_chromium
2016/11/29 16:30:52
For a partial first frame (or partial only frame,
joostouwerling
2016/12/02 16:08:42
Yes, the current behavior is that any failure inva
| |
60 // a parse error occurs before any frames were received. | |
61 // 2) When a decoding failure occurs for non-first frames, we still want to | |
62 // show earlier frames. This means the frame count needs to be adjusted. | |
63 // 3) When a parsing failure occurs, the frame count is adjusted to the number | |
64 // of successfully parsed frames, since we can still show those. | |
65 // | |
66 // In cases 2 and 3, we have to prevent parse() from adjusting the frame | |
67 // count to pre-failure values by setting |m_failedWithCorrectFrames| to true. | |
68 bool setFailed() override; | |
48 | 69 |
49 // Callbacks from libpng | 70 // Callbacks from libpng |
50 void headerAvailable(); | 71 void headerAvailable(); |
51 void rowAvailable(unsigned char* row, unsigned rowIndex, int); | 72 void rowAvailable(unsigned char* row, unsigned rowIndex, int); |
52 void complete(); | 73 void complete(); |
53 | 74 |
75 // Additional methods used for APNG | |
76 void setRepetitionCount(size_t); | |
77 | |
54 private: | 78 private: |
55 // ImageDecoder: | 79 // ImageDecoder: |
56 void decodeSize() override { decode(true); } | 80 void decodeSize() override { parse(PNGParseQuery::PNGSizeQuery); } |
57 void decode(size_t) override { decode(false); } | 81 void decode(size_t) override; |
82 size_t decodeFrameCount() override; | |
83 void initializeNewFrame(size_t) override; | |
84 void clearFrameBuffer(size_t) override; | |
58 | 85 |
59 // Decodes the image. If |onlySize| is true, stops decoding after | 86 bool initFrameBuffer(size_t); |
60 // calculating the image size. If decoding fails but there is no more | 87 void parse(PNGParseQuery); |
61 // data coming, sets the "decode failure" flag. | 88 // Used by clearCacheExceptFrame if two frames need to be kept in cache. |
62 void decode(bool onlySize); | 89 size_t clearCacheExceptTwoFrames(size_t, size_t); |
63 | 90 |
64 std::unique_ptr<PNGImageReader> m_reader; | 91 std::unique_ptr<PNGImageReader> m_reader; |
65 const unsigned m_offset; | 92 const unsigned m_offset; |
93 size_t m_frameCount; | |
94 size_t m_currentFrame; | |
95 // m_repetitionCount is set to cAnimationLoopOnce by default, so the | |
96 // DeferredImageDecoder takes into account that this may be an animated | |
97 // image, but we don't know for sure yet. | |
98 int m_repetitionCount; | |
99 // This flag is set to true if the color space has been set. This is used to | |
100 // prevent setting the color space in each frame, which is unnecessary since | |
101 // frames don't have their own color space. | |
102 bool m_colorSpaceSet; | |
103 bool m_hasAlphaChannel; | |
104 bool m_currentBufferSawAlpha; | |
105 | |
106 // This flag is set to true while PNGImageReader is parsing. This is used by | |
107 // setFailed() to determine how to handle a failure. | |
108 bool m_isParsing; | |
109 // This flag is set to true when a failure has occured, but there are earlier | |
110 // frames that can still be shown. In that case, the frame count is lowered. | |
111 // This flag prevents from calling parse() again, which could change the frame | |
112 // count back to the pre-failure value. | |
113 bool m_failedWithCorrectFrames; | |
66 }; | 114 }; |
67 | 115 |
68 } // namespace blink | 116 } // namespace blink |
69 | 117 |
70 #endif | 118 #endif |
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