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 "include/codec/SkCodec.h" 11#include "include/core/SkEncodedImageFormat.h" 12#include "include/core/SkImageInfo.h" 13#include "include/core/SkPngChunkReader.h" 14#include "include/core/SkRefCnt.h" 15#include "src/codec/SkColorTable.h" 16#include "src/codec/SkSwizzler.h" 17 18class SkStream; 19 20class SkPngCodec : public SkCodec { 21public: 22 static bool IsPng(const void*, size_t); 23 24 // Assume IsPng was called and returned true. 25 static std::unique_ptr<SkCodec> MakeFromStream(std::unique_ptr<SkStream>, Result*, 26 SkPngChunkReader* = nullptr); 27 28 // FIXME (scroggo): Temporarily needed by AutoCleanPng. 29 void setIdatLength(size_t len) { fIdatLength = len; } 30 31 ~SkPngCodec() override; 32 33protected: 34 // We hold the png_ptr and info_ptr as voidp to avoid having to include png.h 35 // or forward declare their types here. voidp auto-casts to the real pointer types. 36 struct voidp { 37 voidp(void* ptr) : fPtr(ptr) {} 38 39 template <typename T> 40 operator T*() const { return (T*)fPtr; } 41 42 explicit operator bool() const { return fPtr != nullptr; } 43 44 void* fPtr; 45 }; 46 47 SkPngCodec(SkEncodedInfo&&, std::unique_ptr<SkStream>, SkPngChunkReader*, 48 void* png_ptr, void* info_ptr, int bitDepth); 49 50 Result onGetPixels(const SkImageInfo&, void*, size_t, const Options&, int*) 51 override; 52 SkEncodedImageFormat onGetEncodedFormat() const override { return SkEncodedImageFormat::kPNG; } 53 bool onRewind() override; 54 55 SkSampler* getSampler(bool createIfNecessary) override; 56 void applyXformRow(void* dst, const void* src); 57 58 voidp png_ptr() { return fPng_ptr; } 59 voidp info_ptr() { return fInfo_ptr; } 60 61 SkSwizzler* swizzler() { return fSwizzler.get(); } 62 63 // Initialize variables used by applyXformRow. 64 void initializeXformParams(); 65 66 /** 67 * Pass available input to libpng to process it. 68 * 69 * libpng will call any relevant callbacks installed. This will continue decoding 70 * until it reaches the end of the file, or until a callback tells libpng to stop. 71 */ 72 bool processData(); 73 74 Result onStartIncrementalDecode(const SkImageInfo& dstInfo, void* pixels, size_t rowBytes, 75 const SkCodec::Options&) override; 76 Result onIncrementalDecode(int*) override; 77 78 sk_sp<SkPngChunkReader> fPngChunkReader; 79 voidp fPng_ptr; 80 voidp fInfo_ptr; 81 82 // These are stored here so they can be used both by normal decoding and scanline decoding. 83 sk_sp<SkColorTable> fColorTable; // May be unpremul. 84 std::unique_ptr<SkSwizzler> fSwizzler; 85 SkAutoTMalloc<uint8_t> fStorage; 86 void* fColorXformSrcRow; 87 const int fBitDepth; 88 89private: 90 91 enum XformMode { 92 // Requires only a swizzle pass. 93 kSwizzleOnly_XformMode, 94 95 // Requires only a color xform pass. 96 kColorOnly_XformMode, 97 98 // Requires a swizzle and a color xform. 99 kSwizzleColor_XformMode, 100 }; 101 102 bool createColorTable(const SkImageInfo& dstInfo); 103 // Helper to set up swizzler, color xforms, and color table. Also calls png_read_update_info. 104 SkCodec::Result initializeXforms(const SkImageInfo& dstInfo, const Options&); 105 void initializeSwizzler(const SkImageInfo& dstInfo, const Options&, bool skipFormatConversion); 106 void allocateStorage(const SkImageInfo& dstInfo); 107 void destroyReadStruct(); 108 109 virtual Result decodeAllRows(void* dst, size_t rowBytes, int* rowsDecoded) = 0; 110 virtual void setRange(int firstRow, int lastRow, void* dst, size_t rowBytes) = 0; 111 virtual Result decode(int* rowsDecoded) = 0; 112 113 XformMode fXformMode; 114 int fXformWidth; 115 116 size_t fIdatLength; 117 bool fDecodedIdat; 118 119 using INHERITED = SkCodec; 120}; 121#endif // SkPngCodec_DEFINED 122