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comparison: gfx/skia/trunk/src/images/SkDecodingImageGenerator.h
gfx/skia/trunk/src/images/SkDecodingImageGenerator.h
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- TOR_BUG_3246
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- 129ffea94266
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| -1:000000000000 | 0:9461a9a11779 |
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| 1 /* | |
| 2 * Copyright 2013 Google Inc. | |
| 3 * | |
| 4 * Use of this source code is governed by a BSD-style license that can be | |
| 5 * found in the LICENSE file. | |
| 6 */ | |
| 7 | |
| 8 #ifndef SkDecodingImageGenerator_DEFINED | |
| 9 #define SkDecodingImageGenerator_DEFINED | |
| 10 | |
| 11 #include "SkBitmap.h" | |
| 12 #include "SkImageGenerator.h" | |
| 13 | |
| 14 class SkData; | |
| 15 class SkStreamRewindable; | |
| 16 | |
| 17 /** | |
| 18 * An implementation of SkImageGenerator that calls into | |
| 19 * SkImageDecoder. | |
| 20 */ | |
| 21 class SkDecodingImageGenerator : public SkImageGenerator { | |
| 22 public: | |
| 23 virtual ~SkDecodingImageGenerator(); | |
| 24 virtual SkData* refEncodedData() SK_OVERRIDE; | |
| 25 // This implementaion of getInfo() always returns true. | |
| 26 virtual bool getInfo(SkImageInfo* info) SK_OVERRIDE; | |
| 27 virtual bool getPixels(const SkImageInfo& info, | |
| 28 void* pixels, | |
| 29 size_t rowBytes) SK_OVERRIDE; | |
| 30 /** | |
| 31 * These options will be passed on to the image decoder. The | |
| 32 * defaults are sensible. | |
| 33 * | |
| 34 * @param fSampleSize If set to > 1, tells the decoder to return a | |
| 35 * smaller than original bitmap, sampling 1 pixel for | |
| 36 * every size pixels. e.g. if sample size is set to 3, | |
| 37 * then the returned bitmap will be 1/3 as wide and high, | |
| 38 * and will contain 1/9 as many pixels as the original. | |
| 39 * Note: this is a hint, and the codec may choose to | |
| 40 * ignore this, or only approximate the sample size. | |
| 41 * | |
| 42 * @param fDitherImage Set to true if the the decoder should try to | |
| 43 * dither the resulting image when decoding to a smaller | |
| 44 * color-space. The default is true. | |
| 45 * | |
| 46 * @param fRequestedColorType If not given, then use whichever | |
| 47 * config the decoder wants. Else try to use this color | |
| 48 * type. If the decoder won't support this color type, | |
| 49 * SkDecodingImageGenerator::Create will return | |
| 50 * NULL. kIndex_8_SkColorType is not supported. | |
| 51 */ | |
| 52 struct Options { | |
| 53 Options() | |
| 54 : fSampleSize(1) | |
| 55 , fDitherImage(true) | |
| 56 , fUseRequestedColorType(false) | |
| 57 , fRequestedColorType() { } | |
| 58 Options(int sampleSize, bool dither) | |
| 59 : fSampleSize(sampleSize) | |
| 60 , fDitherImage(dither) | |
| 61 , fUseRequestedColorType(false) | |
| 62 , fRequestedColorType() { } | |
| 63 Options(int sampleSize, bool dither, SkColorType colorType) | |
| 64 : fSampleSize(sampleSize) | |
| 65 , fDitherImage(dither) | |
| 66 , fUseRequestedColorType(true) | |
| 67 , fRequestedColorType(colorType) { } | |
| 68 const int fSampleSize; | |
| 69 const bool fDitherImage; | |
| 70 const bool fUseRequestedColorType; | |
| 71 const SkColorType fRequestedColorType; | |
| 72 }; | |
| 73 | |
| 74 /** | |
| 75 * These two functions return a SkImageGenerator that calls into | |
| 76 * SkImageDecoder. They return NULL on failure. | |
| 77 * | |
| 78 * The SkData version of this function is preferred. If the stream | |
| 79 * has an underlying SkData (such as a SkMemoryStream) pass that in. | |
| 80 * | |
| 81 * This object will unref the stream when done or on failure. Since | |
| 82 * streams have internal state (position), the caller should not pass | |
| 83 * a shared stream in. Pass either a new duplicated stream in or | |
| 84 * transfer ownership of the stream. This factory asserts | |
| 85 * stream->unique(). | |
| 86 * | |
| 87 * For example: | |
| 88 * SkStreamRewindable* stream; | |
| 89 * ... | |
| 90 * SkImageGenerator* gen | |
| 91 * = SkDecodingImageGenerator::Create( | |
| 92 * stream->duplicate(), SkDecodingImageGenerator::Options()); | |
| 93 * ... | |
| 94 * SkDELETE(gen); | |
| 95 * | |
| 96 * @param Options (see above) | |
| 97 * | |
| 98 * @return NULL on failure, a new SkImageGenerator on success. | |
| 99 */ | |
| 100 static SkImageGenerator* Create(SkStreamRewindable* stream, | |
| 101 const Options& opt); | |
| 102 | |
| 103 /** | |
| 104 * @param data Contains the encoded image data that will be used by | |
| 105 * the SkDecodingImageGenerator. Will be ref()ed by the | |
| 106 * SkImageGenerator constructor and and unref()ed on deletion. | |
| 107 */ | |
| 108 static SkImageGenerator* Create(SkData* data, const Options& opt); | |
| 109 | |
| 110 private: | |
| 111 SkData* fData; | |
| 112 SkStreamRewindable* fStream; | |
| 113 const SkImageInfo fInfo; | |
| 114 const int fSampleSize; | |
| 115 const bool fDitherImage; | |
| 116 | |
| 117 SkDecodingImageGenerator(SkData* data, | |
| 118 SkStreamRewindable* stream, | |
| 119 const SkImageInfo& info, | |
| 120 int sampleSize, | |
| 121 bool ditherImage); | |
| 122 static SkImageGenerator* Create(SkData*, SkStreamRewindable*, | |
| 123 const Options&); | |
| 124 typedef SkImageGenerator INHERITED; | |
| 125 }; | |
| 126 | |
| 127 // // Example of most basic use case: | |
| 128 // | |
| 129 // bool install_data(SkData* data, SkBitmap* dst) { | |
| 130 // return SkInstallDiscardablePixelRef( | |
| 131 // SkDecodingImageGenerator::Create( | |
| 132 // data, SkDecodingImageGenerator::Options()), dst, NULL); | |
| 133 // } | |
| 134 // bool install_stream(SkStreamRewindable* stream, SkBitmap* dst) { | |
| 135 // return SkInstallDiscardablePixelRef( | |
| 136 // SkDecodingImageGenerator::Create( | |
| 137 // stream, SkDecodingImageGenerator::Options()), dst, NULL); | |
| 138 // } | |
| 139 | |
| 140 #endif // SkDecodingImageGenerator_DEFINED |
