| /* |
| * Copyright 2015 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "SkCodec.h" |
| #include "SkColorTable.h" |
| #include "SkEncodedFormat.h" |
| #include "SkImageInfo.h" |
| #include "SkRefCnt.h" |
| #include "SkSwizzler.h" |
| |
| #ifdef SKIA_PNG_PREFIXED |
| // this must proceed png.h |
| #include "pngprefix.h" |
| #endif |
| #include "png.h" |
| |
| class SkStream; |
| |
| class SkPngCodec : public SkCodec { |
| public: |
| static bool IsPng(SkStream*); |
| |
| // Assume IsPng was called and returned true. |
| static SkCodec* NewFromStream(SkStream*); |
| |
| virtual ~SkPngCodec(); |
| |
| protected: |
| Result onGetPixels(const SkImageInfo&, void*, size_t, const Options&, SkPMColor*, int*, int*) |
| override; |
| SkEncodedFormat onGetEncodedFormat() const override { return kPNG_SkEncodedFormat; } |
| bool onRewind() override; |
| uint32_t onGetFillValue(SkColorType colorType, SkAlphaType alphaType) const override; |
| bool onReallyHasAlpha() const final; |
| |
| // Helper to set up swizzler and color table. Also calls png_read_update_info. |
| Result initializeSwizzler(const SkImageInfo& requestedInfo, const Options&, |
| SkPMColor*, int* ctableCount); |
| SkSampler* getSampler(bool createIfNecessary) override { |
| SkASSERT(fSwizzler); |
| return fSwizzler; |
| } |
| |
| SkPngCodec(const SkImageInfo&, SkStream*, png_structp, png_infop, int, int); |
| |
| png_structp png_ptr() { return fPng_ptr; } |
| SkSwizzler* swizzler() { return fSwizzler; } |
| SkSwizzler::SrcConfig srcConfig() const { return fSrcConfig; } |
| int numberPasses() const { return fNumberPasses; } |
| |
| enum AlphaState { |
| // This class has done no decoding, or threw away its knowledge (in |
| // scanline decodes). |
| kUnknown_AlphaState, |
| // This class found the image (possibly partial, in the case of a |
| // scanline decode) to be opaque. |
| kOpaque_AlphaState, |
| // Ths class found the image to have alpha. |
| kHasAlpha_AlphaState, |
| }; |
| |
| virtual AlphaState alphaInScanlineDecode() const = 0; |
| |
| private: |
| png_structp fPng_ptr; |
| png_infop fInfo_ptr; |
| |
| // These are stored here so they can be used both by normal decoding and scanline decoding. |
| SkAutoTUnref<SkColorTable> fColorTable; // May be unpremul. |
| SkAutoTDelete<SkSwizzler> fSwizzler; |
| |
| SkSwizzler::SrcConfig fSrcConfig; |
| const int fNumberPasses; |
| int fBitDepth; |
| AlphaState fAlphaState; |
| |
| bool decodePalette(bool premultiply, int* ctableCount); |
| void destroyReadStruct(); |
| |
| typedef SkCodec INHERITED; |
| }; |