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 #ifndef SkPngCodec_DEFINED 8 #define SkPngCodec_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/SkGainmapInfo.h" 18 #include "src/codec/SkPngCodecBase.h" 19 20 class SkPngChunkReader; 21 class SkPngCompositeChunkReader; 22 class SkStream; 23 struct SkEncodedInfo; 24 struct SkImageInfo; 25 template <typename T> class SkSpan; 26 27 class SkPngCodec : public SkPngCodecBase { 28 public: 29 static bool IsPng(const void*, size_t); 30 31 // Assume IsPng was called and returned true. 32 static std::unique_ptr<SkCodec> MakeFromStream(std::unique_ptr<SkStream>, Result*, 33 SkPngChunkReader* = nullptr); 34 35 // FIXME (scroggo): Temporarily needed by AutoCleanPng. setIdatLength(size_t len)36 void setIdatLength(size_t len) { fIdatLength = len; } 37 38 bool onGetGainmapCodec(SkGainmapInfo*, std::unique_ptr<SkCodec>*) override; 39 40 bool onGetGainmapInfo(SkGainmapInfo*) override; 41 42 ~SkPngCodec() override; 43 44 protected: 45 // We hold the png_ptr and info_ptr as voidp to avoid having to include png.h 46 // or forward declare their types here. voidp auto-casts to the real pointer types. 47 struct voidp { voidpvoidp48 voidp(void* ptr) : fPtr(ptr) {} 49 50 template <typename T> 51 operator T*() const { return (T*)fPtr; } 52 53 explicit operator bool() const { return fPtr != nullptr; } 54 55 void* fPtr; 56 }; 57 58 SkPngCodec(SkEncodedInfo&&, 59 std::unique_ptr<SkStream>, 60 sk_sp<SkPngCompositeChunkReader>, 61 void* png_ptr, 62 void* info_ptr, 63 std::unique_ptr<SkStream>, 64 std::optional<SkGainmapInfo>); 65 66 Result onGetPixels(const SkImageInfo&, void*, size_t, const Options&, int*) 67 override; 68 bool onRewind() override; 69 png_ptr()70 voidp png_ptr() { return fPng_ptr; } info_ptr()71 voidp info_ptr() { return fInfo_ptr; } 72 73 /** 74 * Pass available input to libpng to process it. 75 * 76 * libpng will call any relevant callbacks installed. This will continue decoding 77 * until it reaches the end of the file, or until a callback tells libpng to stop. 78 */ 79 bool processData(); 80 81 Result onStartIncrementalDecode(const SkImageInfo& dstInfo, void* pixels, size_t rowBytes, 82 const SkCodec::Options&) override; 83 Result onIncrementalDecode(int*) override; 84 85 sk_sp<SkPngCompositeChunkReader> fPngChunkReader; 86 voidp fPng_ptr; 87 voidp fInfo_ptr; 88 89 private: 90 // SkPngCodecBase overrides: 91 std::optional<SkSpan<const PaletteColorEntry>> onTryGetPlteChunk() override; 92 std::optional<SkSpan<const uint8_t>> onTryGetTrnsChunk() override; 93 94 // Thin wrapper around `SkPngCodecBase::initializeXforms` that also sets up 95 // some `libpng`-specific state. 96 Result initializeXforms(const SkImageInfo& dstInfo, const Options&); 97 98 void destroyReadStruct(); 99 100 virtual Result decodeAllRows(void* dst, size_t rowBytes, int* rowsDecoded) = 0; 101 virtual Result setRange(int firstRow, int lastRow, void* dst, size_t rowBytes) = 0; 102 virtual Result decode(int* rowsDecoded) = 0; 103 104 size_t fIdatLength; 105 bool fDecodedIdat; 106 std::unique_ptr<SkStream> fGainmapStream; 107 std::optional<SkGainmapInfo> fGainmapInfo; 108 }; 109 #endif // SkPngCodec_DEFINED 110