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* Copyright 2015 Google Inc.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef SkPngCodec_DEFINED
#define SkPngCodec_DEFINED
#include "include/codec/SkCodec.h"
#include "include/core/SkEncodedImageFormat.h"
#include "include/core/SkImageInfo.h"
#include "include/core/SkPngChunkReader.h"
#include "include/core/SkRefCnt.h"
#include "src/codec/SkColorTable.h"
#include "src/codec/SkSwizzler.h"
class SkStream;
class SkPngCodec : public SkCodec {
static bool IsPng(const void*, size_t);
// Assume IsPng was called and returned true.
static std::unique_ptr<SkCodec> MakeFromStream(std::unique_ptr<SkStream>, Result*,
SkPngChunkReader* = nullptr);
// FIXME (scroggo): Temporarily needed by AutoCleanPng.
void setIdatLength(size_t len) { fIdatLength = len; }
~SkPngCodec() override;
// We hold the png_ptr and info_ptr as voidp to avoid having to include png.h
// or forward declare their types here. voidp auto-casts to the real pointer types.
struct voidp {
voidp(void* ptr) : fPtr(ptr) {}
template <typename T>
operator T*() const { return (T*)fPtr; }
explicit operator bool() const { return fPtr != nullptr; }
void* fPtr;
SkPngCodec(SkEncodedInfo&&, std::unique_ptr<SkStream>, SkPngChunkReader*,
void* png_ptr, void* info_ptr, int bitDepth);
Result onGetPixels(const SkImageInfo&, void*, size_t, const Options&, int*)
SkEncodedImageFormat onGetEncodedFormat() const override { return SkEncodedImageFormat::kPNG; }
bool onRewind() override;
SkSampler* getSampler(bool createIfNecessary) override;
void applyXformRow(void* dst, const void* src);
voidp png_ptr() { return fPng_ptr; }
voidp info_ptr() { return fInfo_ptr; }
SkSwizzler* swizzler() { return fSwizzler.get(); }
// Initialize variables used by applyXformRow.
void initializeXformParams();
* Pass available input to libpng to process it.
* libpng will call any relevant callbacks installed. This will continue decoding
* until it reaches the end of the file, or until a callback tells libpng to stop.
bool processData();
Result onStartIncrementalDecode(const SkImageInfo& dstInfo, void* pixels, size_t rowBytes,
const SkCodec::Options&) override;
Result onIncrementalDecode(int*) override;
sk_sp<SkPngChunkReader> fPngChunkReader;
voidp fPng_ptr;
voidp fInfo_ptr;
// These are stored here so they can be used both by normal decoding and scanline decoding.
sk_sp<SkColorTable> fColorTable; // May be unpremul.
std::unique_ptr<SkSwizzler> fSwizzler;
SkAutoTMalloc<uint8_t> fStorage;
void* fColorXformSrcRow;
const int fBitDepth;
enum XformMode {
// Requires only a swizzle pass.
// Requires only a color xform pass.
// Requires a swizzle and a color xform.
bool createColorTable(const SkImageInfo& dstInfo);
// Helper to set up swizzler, color xforms, and color table. Also calls png_read_update_info.
SkCodec::Result initializeXforms(const SkImageInfo& dstInfo, const Options&);
void initializeSwizzler(const SkImageInfo& dstInfo, const Options&, bool skipFormatConversion);
void allocateStorage(const SkImageInfo& dstInfo);
void destroyReadStruct();
virtual Result decodeAllRows(void* dst, size_t rowBytes, int* rowsDecoded) = 0;
virtual void setRange(int firstRow, int lastRow, void* dst, size_t rowBytes) = 0;
virtual Result decode(int* rowsDecoded) = 0;
XformMode fXformMode;
int fXformWidth;
size_t fIdatLength;
bool fDecodedIdat;
using INHERITED = SkCodec;
#endif // SkPngCodec_DEFINED