1/*
2 * Copyright 2015 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 SkJpegCodec_DEFINED
9#define SkJpegCodec_DEFINED
10
11#include "include/codec/SkCodec.h"
12#include "include/codec/SkEncodedImageFormat.h"
13#include "include/codec/SkEncodedOrigin.h"
14#include "include/core/SkRect.h"
15#include "include/core/SkSize.h"
16#include "include/core/SkTypes.h"
17#include "include/core/SkYUVAPixmaps.h"
18#include "include/private/SkEncodedInfo.h"
19#include "include/private/base/SkTemplates.h"
20
21#include <cstddef>
22#include <cstdint>
23#include <memory>
24
25class JpegDecoderMgr;
26class SkSampler;
27class SkStream;
28class SkSwizzler;
29struct SkGainmapInfo;
30struct SkImageInfo;
31
32/*
33 *
34 * This class implements the decoding for jpeg images
35 *
36 */
37class SkJpegCodec : public SkCodec {
38public:
39 ~SkJpegCodec() override;
40
41 static bool IsJpeg(const void*, size_t);
42
43 /*
44 * Assumes IsJpeg was called and returned true
45 * Takes ownership of the stream
46 */
47 static std::unique_ptr<SkCodec> MakeFromStream(std::unique_ptr<SkStream>, Result*);
48
49protected:
50
51 /*
52 * Recommend a set of destination dimensions given a requested scale
53 */
54 SkISize onGetScaledDimensions(float desiredScale) const override;
55
56 /*
57 * Initiates the jpeg decode
58 */
59 Result onGetPixels(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes, const Options&,
60 int*) override;
61
62 bool onQueryYUVAInfo(const SkYUVAPixmapInfo::SupportedDataTypes&,
63 SkYUVAPixmapInfo*) const override;
64
65 Result onGetYUVAPlanes(const SkYUVAPixmaps& yuvaPixmaps) override;
66
67 SkEncodedImageFormat onGetEncodedFormat() const override {
68 return SkEncodedImageFormat::kJPEG;
69 }
70
71 bool onRewind() override;
72
73 bool onDimensionsSupported(const SkISize&) override;
74
75 bool conversionSupported(const SkImageInfo&, bool, bool) override;
76
77 bool onGetGainmapInfo(SkGainmapInfo* info,
78 std::unique_ptr<SkStream>* gainmapImageStream) override;
79
80private:
81 /*
82 * Allows SkRawCodec to communicate the color profile from the exif data.
83 */
84 static std::unique_ptr<SkCodec> MakeFromStream(std::unique_ptr<SkStream>, Result*,
85 std::unique_ptr<SkEncodedInfo::ICCProfile> defaultColorProfile);
86
87 /*
88 * Read enough of the stream to initialize the SkJpegCodec.
89 * Returns a bool representing success or failure.
90 *
91 * @param codecOut
92 * If this returns true, and codecOut was not nullptr,
93 * codecOut will be set to a new SkJpegCodec.
94 *
95 * @param decoderMgrOut
96 * If this returns true, and codecOut was nullptr,
97 * decoderMgrOut must be non-nullptr and decoderMgrOut will be set to a new
98 * JpegDecoderMgr pointer.
99 *
100 * @param stream
101 * Deleted on failure.
102 * codecOut will take ownership of it in the case where we created a codec.
103 * Ownership is unchanged when we set decoderMgrOut.
104 *
105 * @param defaultColorProfile
106 * If the jpeg does not have an embedded color profile, the image data should
107 * be tagged with this color profile.
108 */
109 static Result ReadHeader(SkStream* stream, SkCodec** codecOut,
110 JpegDecoderMgr** decoderMgrOut,
111 std::unique_ptr<SkEncodedInfo::ICCProfile> defaultColorProfile);
112
113 /*
114 * Creates an instance of the decoder
115 * Called only by NewFromStream
116 *
117 * @param info contains properties of the encoded data
118 * @param stream the encoded image data
119 * @param decoderMgr holds decompress struct, src manager, and error manager
120 * takes ownership
121 * @param origin indicates the image orientation as specified in Exif metadata.
122 * @param xmpMetadata holds the XMP metadata included in the image, if any.
123 */
124 SkJpegCodec(SkEncodedInfo&& info,
125 std::unique_ptr<SkStream> stream,
126 JpegDecoderMgr* decoderMgr,
127 SkEncodedOrigin origin);
128
129 void initializeSwizzler(const SkImageInfo& dstInfo, const Options& options,
130 bool needsCMYKToRGB);
131 [[nodiscard]] bool allocateStorage(const SkImageInfo& dstInfo);
132 int readRows(const SkImageInfo& dstInfo, void* dst, size_t rowBytes, int count, const Options&);
133
134 /*
135 * Scanline decoding.
136 */
137 SkSampler* getSampler(bool createIfNecessary) override;
138 Result onStartScanlineDecode(const SkImageInfo& dstInfo,
139 const Options& options) override;
140 int onGetScanlines(void* dst, int count, size_t rowBytes) override;
141 bool onSkipScanlines(int count) override;
142
143 std::unique_ptr<JpegDecoderMgr> fDecoderMgr;
144
145 // We will save the state of the decompress struct after reading the header.
146 // This allows us to safely call onGetScaledDimensions() at any time.
147 const int fReadyState;
148
149
150 skia_private::AutoTMalloc<uint8_t> fStorage;
151 uint8_t* fSwizzleSrcRow = nullptr;
152 uint32_t* fColorXformSrcRow = nullptr;
153
154 // libjpeg-turbo provides some subsetting. In the case that libjpeg-turbo
155 // cannot take the exact the subset that we need, we will use the swizzler
156 // to further subset the output from libjpeg-turbo.
157 SkIRect fSwizzlerSubset = SkIRect::MakeEmpty();
158
159 std::unique_ptr<SkSwizzler> fSwizzler;
160
161 friend class SkRawCodec;
162
163 using INHERITED = SkCodec;
164};
165
166#endif
167

source code of flutter_engine/third_party/skia/src/codec/SkJpegCodec.h