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 #include "SkCodec.h" 9 #include "SkColorTable.h" 10 #include "SkPngChunkReader.h" 11 #include "SkEncodedFormat.h" 12 #include "SkImageInfo.h" 13 #include "SkRefCnt.h" 14 #include "SkSwizzler.h" 15 16 #include "png.h" 17 18 class SkStream; 19 20 class SkPngCodec : public SkCodec { 21 public: 22 static bool IsPng(const char*, size_t); 23 24 // Assume IsPng was called and returned true. 25 static SkCodec* NewFromStream(SkStream*, SkPngChunkReader* = NULL); 26 27 virtual ~SkPngCodec(); 28 29 protected: 30 Result onGetPixels(const SkImageInfo&, void*, size_t, const Options&, SkPMColor*, int*, int*) 31 override; onGetEncodedFormat()32 SkEncodedFormat onGetEncodedFormat() const override { return kPNG_SkEncodedFormat; } 33 bool onRewind() override; 34 uint32_t onGetFillValue(SkColorType) const override; 35 36 // Helper to set up swizzler and color table. Also calls png_read_update_info. 37 Result initializeSwizzler(const SkImageInfo& requestedInfo, const Options&, 38 SkPMColor*, int* ctableCount); getSampler(bool createIfNecessary)39 SkSampler* getSampler(bool createIfNecessary) override { 40 SkASSERT(fSwizzler); 41 return fSwizzler; 42 } 43 44 SkPngCodec(const SkImageInfo&, SkStream*, SkPngChunkReader*, png_structp, png_infop, int, int); 45 png_ptr()46 png_structp png_ptr() { return fPng_ptr; } swizzler()47 SkSwizzler* swizzler() { return fSwizzler; } srcConfig()48 SkSwizzler::SrcConfig srcConfig() const { return fSrcConfig; } numberPasses()49 int numberPasses() const { return fNumberPasses; } 50 51 private: 52 SkAutoTUnref<SkPngChunkReader> fPngChunkReader; 53 png_structp fPng_ptr; 54 png_infop fInfo_ptr; 55 56 // These are stored here so they can be used both by normal decoding and scanline decoding. 57 SkAutoTUnref<SkColorTable> fColorTable; // May be unpremul. 58 SkAutoTDelete<SkSwizzler> fSwizzler; 59 60 SkSwizzler::SrcConfig fSrcConfig; 61 const int fNumberPasses; 62 int fBitDepth; 63 64 bool decodePalette(bool premultiply, int* ctableCount); 65 void destroyReadStruct(); 66 67 typedef SkCodec INHERITED; 68 }; 69