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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 SkJpegCodec_DEFINED
#define SkJpegCodec_DEFINED
#include "include/codec/SkCodec.h"
#include "include/codec/SkEncodedOrigin.h"
#include "include/core/SkEncodedImageFormat.h"
#include "include/core/SkRect.h"
#include "include/core/SkRefCnt.h"
#include "include/core/SkSize.h"
#include "include/core/SkTypes.h"
#include "include/core/SkYUVAPixmaps.h"
#include "include/private/SkEncodedInfo.h"
#include "include/private/SkTemplates.h"
#include <cstddef>
#include <cstdint>
#include <memory>
class JpegDecoderMgr;
class SkData;
class SkSampler;
class SkStream;
class SkSwizzler;
struct SkGainmapInfo;
struct SkImageInfo;
* This class implements the decoding for jpeg images
class SkJpegCodec : public SkCodec {
~SkJpegCodec() override;
static bool IsJpeg(const void*, size_t);
* Assumes IsJpeg was called and returned true
* Takes ownership of the stream
static std::unique_ptr<SkCodec> MakeFromStream(std::unique_ptr<SkStream>, Result*);
* Recommend a set of destination dimensions given a requested scale
SkISize onGetScaledDimensions(float desiredScale) const override;
* Initiates the jpeg decode
Result onGetPixels(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes, const Options&,
int*) override;
bool onQueryYUVAInfo(const SkYUVAPixmapInfo::SupportedDataTypes&,
SkYUVAPixmapInfo*) const override;
Result onGetYUVAPlanes(const SkYUVAPixmaps& yuvaPixmaps) override;
SkEncodedImageFormat onGetEncodedFormat() const override {
return SkEncodedImageFormat::kJPEG;
bool onRewind() override;
bool onDimensionsSupported(const SkISize&) override;
bool conversionSupported(const SkImageInfo&, bool, bool) override;
bool onGetGainmapInfo(SkGainmapInfo* info,
std::unique_ptr<SkStream>* gainmapImageStream) override;
* Allows SkRawCodec to communicate the color profile from the exif data.
static std::unique_ptr<SkCodec> MakeFromStream(std::unique_ptr<SkStream>, Result*,
std::unique_ptr<SkEncodedInfo::ICCProfile> defaultColorProfile);
* Read enough of the stream to initialize the SkJpegCodec.
* Returns a bool representing success or failure.
* @param codecOut
* If this returns true, and codecOut was not nullptr,
* codecOut will be set to a new SkJpegCodec.
* @param decoderMgrOut
* If this returns true, and codecOut was nullptr,
* decoderMgrOut must be non-nullptr and decoderMgrOut will be set to a new
* JpegDecoderMgr pointer.
* @param stream
* Deleted on failure.
* codecOut will take ownership of it in the case where we created a codec.
* Ownership is unchanged when we set decoderMgrOut.
* @param defaultColorProfile
* If the jpeg does not have an embedded color profile, the image data should
* be tagged with this color profile.
static Result ReadHeader(SkStream* stream, SkCodec** codecOut,
JpegDecoderMgr** decoderMgrOut,
std::unique_ptr<SkEncodedInfo::ICCProfile> defaultColorProfile);
* Creates an instance of the decoder
* Called only by NewFromStream
* @param info contains properties of the encoded data
* @param stream the encoded image data
* @param decoderMgr holds decompress struct, src manager, and error manager
* takes ownership
* @param origin indicates the image orientation as specified in Exif metadata.
* @param xmpMetadata holds the XMP metadata included in the image, if any.
SkJpegCodec(SkEncodedInfo&& info,
std::unique_ptr<SkStream> stream,
JpegDecoderMgr* decoderMgr,
SkEncodedOrigin origin,
sk_sp<const SkData> xmpMetadata);
void initializeSwizzler(const SkImageInfo& dstInfo, const Options& options,
bool needsCMYKToRGB);
bool SK_WARN_UNUSED_RESULT allocateStorage(const SkImageInfo& dstInfo);
int readRows(const SkImageInfo& dstInfo, void* dst, size_t rowBytes, int count, const Options&);
* Scanline decoding.
SkSampler* getSampler(bool createIfNecessary) override;
Result onStartScanlineDecode(const SkImageInfo& dstInfo,
const Options& options) override;
int onGetScanlines(void* dst, int count, size_t rowBytes) override;
bool onSkipScanlines(int count) override;
std::unique_ptr<JpegDecoderMgr> fDecoderMgr;
// We will save the state of the decompress struct after reading the header.
// This allows us to safely call onGetScaledDimensions() at any time.
const int fReadyState;
SkAutoTMalloc<uint8_t> fStorage;
uint8_t* fSwizzleSrcRow = nullptr;
uint32_t* fColorXformSrcRow = nullptr;
// libjpeg-turbo provides some subsetting. In the case that libjpeg-turbo
// cannot take the exact the subset that we need, we will use the swizzler
// to further subset the output from libjpeg-turbo.
SkIRect fSwizzlerSubset = SkIRect::MakeEmpty();
std::unique_ptr<SkSwizzler> fSwizzler;
friend class SkRawCodec;
using INHERITED = SkCodec;