1 /* 2 * Copyright 2024 Google LLC. 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 #ifndef SkPngCodecBase_DEFINED 8 #define SkPngCodecBase_DEFINED 9 10 #include <cstddef> 11 #include <cstdint> 12 #include <memory> 13 #include <optional> 14 15 #include "include/codec/SkCodec.h" 16 #include "include/core/SkRefCnt.h" 17 #include "include/private/SkEncodedInfo.h" 18 #include "include/private/base/SkDebug.h" 19 #include "include/private/base/SkTemplates.h" 20 21 class SkColorPalette; 22 class SkSampler; 23 class SkStream; 24 class SkSwizzler; 25 enum class SkEncodedImageFormat; 26 struct SkImageInfo; 27 template <typename T> class SkSpan; 28 29 // This class implements functionality shared between `SkPngCodec` and 30 // `SkPngRustCodec` (the latter is from `experimental/rust_png`). 31 class SkPngCodecBase : public SkCodec { 32 public: 33 ~SkPngCodecBase() override; 34 35 static bool isCompatibleColorProfileAndType(const SkEncodedInfo::ICCProfile* profile, 36 SkEncodedInfo::Color color); 37 protected: 38 SkPngCodecBase(SkEncodedInfo&&, std::unique_ptr<SkStream>); 39 40 // Initialize most fields needed by `applyXformRow`. 41 // 42 // Each call to `applyXformRow` will transform `frameWidth` pixels 43 // (which may be less than `dstInfo.width()` when decoding frames that 44 // depend on earlier frames). 45 Result initializeXforms(const SkImageInfo& dstInfo, const Options& options, int frameWidth); 46 47 // Initialize other fields needed by `applyXformRow`. 48 // 49 // Needs to be called *after* (i.e. outside of) `onStartIncrementalDecode`. 50 void initializeXformParams(); 51 52 // Transforms a decoded row into the `dstInfo` format that was earlier 53 // passed to `initializeXforms`. 54 // 55 // The first bytes/pixels of `srcRow` will be transformed into the first 56 // bytes/pixels of `dstRow`. In other words, the transformation ignores 57 // `fcTL.x_offset` field - the caller should offset `dstRow` if desired 58 // (it may not be desirable when working with interlaced rows which are 59 // first transformed into an intermediate buffer). 60 void applyXformRow(SkSpan<uint8_t> dstRow, SkSpan<const uint8_t> srcRow); 61 void applyXformRow(void* dstRow, const uint8_t* srcRow); 62 getEncodedRowBytes()63 size_t getEncodedRowBytes() const { return fEncodedRowBytes; } swizzler()64 const SkSwizzler* swizzler() const { return fSwizzler.get(); } 65 66 struct PaletteColorEntry { 67 uint8_t red; 68 uint8_t green; 69 uint8_t blue; 70 }; 71 virtual std::optional<SkSpan<const PaletteColorEntry>> onTryGetPlteChunk() = 0; 72 virtual std::optional<SkSpan<const uint8_t>> onTryGetTrnsChunk() = 0; 73 74 private: 75 // SkCodec overrides: 76 SkEncodedImageFormat onGetEncodedFormat() const final; 77 SkSampler* getSampler(bool createIfNecessary) final; 78 79 void allocateStorage(const SkImageInfo& dstInfo); 80 Result initializeSwizzler(const SkImageInfo& dstInfo, 81 const Options& options, 82 bool skipFormatConversion, 83 int frameWidth); 84 bool createColorTable(const SkImageInfo& dstInfo); 85 86 enum XformMode { 87 // Requires only a swizzle pass. 88 kSwizzleOnly_XformMode, 89 90 // Requires only a color xform pass. 91 kColorOnly_XformMode, 92 93 // Requires a swizzle and a color xform. 94 kSwizzleColor_XformMode, 95 }; 96 XformMode fXformMode; 97 98 std::unique_ptr<SkSwizzler> fSwizzler; 99 skia_private::AutoTMalloc<uint8_t> fStorage; 100 int fXformWidth = -1; 101 sk_sp<SkColorPalette> fColorTable; // May be unpremul. 102 103 size_t fEncodedRowBytes = 0; // Size of encoded/source row in bytes. 104 #if defined(SK_DEBUG) 105 size_t fDstRowBytes = 0; // Size of destination row in bytes. 106 #endif 107 }; 108 109 #endif // SkPngCodecBase_DEFINED 110