#include <SkPngCodec.h>

Inheritance diagram for SkPngCodec:

Classes
struct	voidp

Public Member Functions
void	setIdatLength (size_t len)

	~SkPngCodec () override

Public Member Functions inherited from SkCodec
virtual	~SkCodec ()

SkImageInfo	getInfo () const

SkISize	dimensions () const

SkIRect	bounds () const

const skcms_ICCProfile *	getICCProfile () const

SkEncodedOrigin	getOrigin () const

SkISize	getScaledDimensions (float desiredScale) const

bool	getValidSubset (SkIRect *desiredSubset) const

SkEncodedImageFormat	getEncodedFormat () const

virtual std::unique_ptr< SkStream >	getEncodedData () const

Result	getPixels (const SkImageInfo &info, void pixels, size_t rowBytes, const Options )

Result	getPixels (const SkImageInfo &info, void *pixels, size_t rowBytes)

Result	getPixels (const SkPixmap &pm, const Options *opts=nullptr)

std::tuple< sk_sp< SkImage >, SkCodec::Result >	getImage (const SkImageInfo &info, const Options *opts=nullptr)

std::tuple< sk_sp< SkImage >, SkCodec::Result >	getImage ()

bool	queryYUVAInfo (const SkYUVAPixmapInfo::SupportedDataTypes &supportedDataTypes, SkYUVAPixmapInfo *yuvaPixmapInfo) const

Result	getYUVAPlanes (const SkYUVAPixmaps &yuvaPixmaps)

Result	startIncrementalDecode (const SkImageInfo &dstInfo, void dst, size_t rowBytes, const Options )

Result	startIncrementalDecode (const SkImageInfo &dstInfo, void *dst, size_t rowBytes)

Result	incrementalDecode (int *rowsDecoded=nullptr)

Result	startScanlineDecode (const SkImageInfo &dstInfo, const Options *options)

Result	startScanlineDecode (const SkImageInfo &dstInfo)

int	getScanlines (void *dst, int countLines, size_t rowBytes)

bool	skipScanlines (int countLines)

SkScanlineOrder	getScanlineOrder () const

int	nextScanline () const

int	outputScanline (int inputScanline) const

int	getFrameCount ()

bool	getFrameInfo (int index, FrameInfo *info) const

std::vector< FrameInfo >	getFrameInfo ()

int	getRepetitionCount ()

Static Public Member Functions
static bool	IsPng (const void *, size_t)

static std::unique_ptr< SkCodec >	MakeFromStream (std::unique_ptr< SkStream >, Result , SkPngChunkReader =nullptr)

Static Public Member Functions inherited from SkCodec
static constexpr size_t	MinBufferedBytesNeeded ()

static const char *	ResultToString (Result)

static std::unique_ptr< SkCodec >	MakeFromStream (std::unique_ptr< SkStream >, SkSpan< const SkCodecs::Decoder > decoders, Result =nullptr, SkPngChunkReader =nullptr, SelectionPolicy selectionPolicy=SelectionPolicy::kPreferStillImage)

static std::unique_ptr< SkCodec >	MakeFromStream (std::unique_ptr< SkStream >, Result =nullptr, SkPngChunkReader =nullptr, SelectionPolicy selectionPolicy=SelectionPolicy::kPreferStillImage)

static std::unique_ptr< SkCodec >	MakeFromData (sk_sp< SkData >, SkSpan< const SkCodecs::Decoder > decoders, SkPngChunkReader *=nullptr)

static std::unique_ptr< SkCodec >	MakeFromData (sk_sp< SkData >, SkPngChunkReader *=nullptr)

static void	Register (bool(peek)(const void , size_t), std::unique_ptr< SkCodec >(make)(std::unique_ptr< SkStream >, SkCodec::Result ))

Protected Member Functions
	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 ) override

SkEncodedImageFormat	onGetEncodedFormat () const override

bool	onRewind () override

SkSampler *	getSampler (bool createIfNecessary) override

void	applyXformRow (void dst, const void src)

voidp	png_ptr ()

voidp	info_ptr ()

SkSwizzler *	swizzler ()

void	initializeXformParams ()

bool	processData ()

Result	onStartIncrementalDecode (const SkImageInfo &dstInfo, void *pixels, size_t rowBytes, const SkCodec::Options &) override

Result	onIncrementalDecode (int *) override

Protected Member Functions inherited from SkCodec
const SkEncodedInfo &	getEncodedInfo () const

	SkCodec (SkEncodedInfo &&, XformFormat srcFormat, std::unique_ptr< SkStream >, SkEncodedOrigin=kTopLeft_SkEncodedOrigin)

void	setSrcXformFormat (XformFormat pixelFormat)

XformFormat	getSrcXformFormat () const

virtual bool	onGetGainmapInfo (SkGainmapInfo , std::unique_ptr< SkStream > )

virtual SkISize	onGetScaledDimensions (float) const

virtual bool	onDimensionsSupported (const SkISize &)

virtual SkEncodedImageFormat	onGetEncodedFormat () const =0

virtual Result	onGetPixels (const SkImageInfo &info, void pixels, size_t rowBytes, const Options &, int rowsDecoded)=0

virtual bool	onQueryYUVAInfo (const SkYUVAPixmapInfo::SupportedDataTypes &, SkYUVAPixmapInfo *) const

virtual Result	onGetYUVAPlanes (const SkYUVAPixmaps &)

virtual bool	onGetValidSubset (SkIRect *) const

bool	rewindIfNeeded ()

virtual bool	onRewind ()

SkStream *	stream ()

virtual SkScanlineOrder	onGetScanlineOrder () const

const SkImageInfo &	dstInfo () const

const Options &	options () const

int	currScanline () const

virtual int	onOutputScanline (int inputScanline) const

virtual bool	conversionSupported (const SkImageInfo &dst, bool srcIsOpaque, bool needsColorXform)

virtual bool	usesColorXform () const

void	applyColorXform (void dst, const void src, int count) const

bool	colorXform () const

bool	xformOnDecode () const

virtual int	onGetFrameCount ()

virtual bool	onGetFrameInfo (int, FrameInfo *) const

virtual int	onGetRepetitionCount ()

Protected Attributes
sk_sp< SkPngChunkReader >	fPngChunkReader

voidp	fPng_ptr

voidp	fInfo_ptr

sk_sp< SkColorPalette >	fColorTable

std::unique_ptr< SkSwizzler >	fSwizzler

skia_private::AutoTMalloc< uint8_t >	fStorage

void *	fColorXformSrcRow

const int	fBitDepth

Private Member Functions
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

Additional Inherited Members
Public Types inherited from SkCodec
enum	Result { kSuccess , kIncompleteInput , kErrorInInput , kInvalidConversion , kInvalidScale , kInvalidParameters , kInvalidInput , kCouldNotRewind , kInternalError , kUnimplemented }

enum class	SelectionPolicy { kPreferStillImage , kPreferAnimation }

enum	ZeroInitialized { kYes_ZeroInitialized , kNo_ZeroInitialized }

enum	SkScanlineOrder { kTopDown_SkScanlineOrder , kBottomUp_SkScanlineOrder }

Static Public Attributes inherited from SkCodec
static constexpr int	kNoFrame = -1

static constexpr int	kRepetitionCountInfinite = -1

Protected Types inherited from SkCodec
using	XformFormat = skcms_PixelFormat

Detailed Description

Definition at line 27 of file SkPngCodec.h.

Constructor & Destructor Documentation

◆ ~SkPngCodec()

SkPngCodec::~SkPngCodec ( )

override

Definition at line 1017 of file SkPngCodec.cpp.

                        {
    this->destroyReadStruct();
}

◆ SkPngCodec()

SkPngCodec::SkPngCodec	(	SkEncodedInfo &&	encodedInfo,
		std::unique_ptr< SkStream >	stream,
		SkPngChunkReader *	chunkReader,
		void *	png_ptr,
		void *	info_ptr,
		int	bitDepth
	)

protected

Definition at line 1005 of file SkPngCodec.cpp.

    : INHERITED(std::move(encodedInfo), png_select_xform_format(encodedInfo), std::move(stream))
    , fPngChunkReader(SkSafeRef(chunkReader))
    , fPng_ptr(png_ptr)
    , fInfo_ptr(info_ptr)
    , fColorXformSrcRow(nullptr)
    , fBitDepth(bitDepth)
    , fIdatLength(0)
    , fDecodedIdat(false)
{}

Member Function Documentation

◆ applyXformRow()

void SkPngCodec::applyXformRow	(	void *	dst,
		const void *	src
	)

protected

Definition at line 486 of file SkPngCodec.cpp.

                                                         {
    switch (fXformMode) {
        case kSwizzleOnly_XformMode:
            fSwizzler->swizzle(dst, (const uint8_t*) src);
            break;
        case kColorOnly_XformMode:
            this->applyColorXform(dst, src, fXformWidth);
            break;
        case kSwizzleColor_XformMode:
            fSwizzler->swizzle(fColorXformSrcRow, (const uint8_t*) src);
            this->applyColorXform(dst, fColorXformSrcRow, fXformWidth);
            break;
    }
}

◆ decode()

virtual Result SkPngCodec::decode ( int * rowsDecoded )

privatepure virtual

◆ decodeAllRows()

virtual Result SkPngCodec::decodeAllRows	(	void *	dst,
		size_t	rowBytes,
		int *	rowsDecoded
	)

privatepure virtual

◆ getSampler()

SkSampler * SkPngCodec::getSampler ( bool )

overrideprotectedvirtual

Return an object which will allow forcing scanline decodes to sample in X.

May create a sampler, if one is not currently being used. Otherwise, does not affect ownership.

Only valid during scanline decoding or incremental decoding.

Reimplemented from SkCodec.

Definition at line 1141 of file SkPngCodec.cpp.

                                                        {
    if (fSwizzler || !createIfNecessary) {
        return fSwizzler.get();
    }
 
    this->initializeSwizzler(this->dstInfo(), this->options(), true);
    return fSwizzler.get();
}

◆ info_ptr()

voidp SkPngCodec::info_ptr ( )

inlineprotected

Definition at line 66 of file SkPngCodec.h.

66{ return fInfo_ptr; }

◆ initializeXformParams()

void SkPngCodec::initializeXformParams ( )

protected

Definition at line 1077 of file SkPngCodec.cpp.

                                       {
    switch (fXformMode) {
        case kColorOnly_XformMode:
            fXformWidth = this->dstInfo().width();
            break;
        case kSwizzleColor_XformMode:
            fXformWidth = this->swizzler()->swizzleWidth();
            break;
        default:
            break;
    }
}

◆ IsPng()

bool SkPngCodec::IsPng	(	const void *	buf,
		size_t	bytesRead
	)

static

Definition at line 344 of file SkPngCodec.cpp.

                                                        {
    return !png_sig_cmp((png_const_bytep) buf, (png_size_t)0, bytesRead);
}

◆ MakeFromStream()

std::unique_ptr< SkCodec > SkPngCodec::MakeFromStream	(	std::unique_ptr< SkStream >	stream,
		Result *	result,
		SkPngChunkReader *	chunkReader = `nullptr`
	)

static

Definition at line 1216 of file SkPngCodec.cpp.

                                                                                                   {
    SkASSERT(result);
    if (!stream) {
        *result = SkCodec::kInvalidInput;
        return nullptr;
    }
    SkCodec* outCodec = nullptr;
    *result = read_header(stream.get(), chunkReader, &outCodec, nullptr, nullptr);
    if (kSuccess == *result) {
        // Codec has taken ownership of the stream.
        SkASSERT(outCodec);
        stream.release();
    }
    return std::unique_ptr<SkCodec>(outCodec);
}

◆ onGetEncodedFormat()

SkEncodedImageFormat SkPngCodec::onGetEncodedFormat ( ) const

inlineoverrideprotectedvirtual

Implements SkCodec.

Definition at line 59 of file SkPngCodec.h.

59{ return SkEncodedImageFormat::kPNG; }

SkEncodedImageFormat::kPNG

@ kPNG

◆ onGetPixels()

SkCodec::Result SkPngCodec::onGetPixels	(	const SkImageInfo &	info,
		void *	pixels,
		size_t	rowBytes,
		const Options &	,
		int *	rowsDecoded
	)

overrideprotectedvirtual

Parameters

rowsDecoded When the encoded image stream is incomplete, this function will return kIncompleteInput and rowsDecoded will be set to the number of scanlines that were successfully decoded. This will allow getPixels() to fill the uninitialized memory.

Implements SkCodec.

Definition at line 1171 of file SkPngCodec.cpp.

                                                          {
    Result result = this->initializeXforms(dstInfo, options);
    if (kSuccess != result) {
        return result;
    }
 
    if (options.fSubset) {
        return kUnimplemented;
    }
 
    this->allocateStorage(dstInfo);
    this->initializeXformParams();
    return this->decodeAllRows(dst, rowBytes, rowsDecoded);
}

◆ onIncrementalDecode()

SkCodec::Result SkPngCodec::onIncrementalDecode ( int * rowsDecoded )

overrideprotectedvirtual

Reimplemented from SkCodec.

Definition at line 1209 of file SkPngCodec.cpp.

                                                              {
    // FIXME: Only necessary on the first call.
    this->initializeXformParams();
 
    return this->decode(rowsDecoded);
}

◆ onRewind()

bool SkPngCodec::onRewind ( )

overrideprotectedvirtual

Called by rewindIfNeeded, if the stream needed to be rewound.

Subclasses should do any set up needed after a rewind.

Reimplemented from SkCodec.

Definition at line 1150 of file SkPngCodec.cpp.

                          {
    // This sets fPng_ptr and fInfo_ptr to nullptr. If read_header
    // succeeds, they will be repopulated, and if it fails, they will
    // remain nullptr. Any future accesses to fPng_ptr and fInfo_ptr will
    // come through this function which will rewind and again attempt
    // to reinitialize them.
    this->destroyReadStruct();
 
    png_structp png_ptr;
    png_infop info_ptr;
    if (kSuccess != read_header(this->stream(), fPngChunkReader.get(), nullptr,
                                &png_ptr, &info_ptr)) {
        return false;
    }
 
    fPng_ptr = png_ptr;
    fInfo_ptr = info_ptr;
    fDecodedIdat = false;
    return true;
}

◆ onStartIncrementalDecode()

SkCodec::Result SkPngCodec::onStartIncrementalDecode	(	const SkImageInfo &	dstInfo,
		void *	pixels,
		size_t	rowBytes,
		const SkCodec::Options &	options
	)

overrideprotectedvirtual

Reimplemented from SkCodec.

Definition at line 1188 of file SkPngCodec.cpp.

                                                                   {
    Result result = this->initializeXforms(dstInfo, options);
    if (kSuccess != result) {
        return result;
    }
 
    this->allocateStorage(dstInfo);
 
    int firstRow, lastRow;
    if (options.fSubset) {
        firstRow = options.fSubset->top();
        lastRow = options.fSubset->bottom() - 1;
    } else {
        firstRow = 0;
        lastRow = dstInfo.height() - 1;
    }
    this->setRange(firstRow, lastRow, dst, rowBytes);
    return kSuccess;
}

◆ png_ptr()

voidp SkPngCodec::png_ptr ( )

inlineprotected

Definition at line 65 of file SkPngCodec.h.

65{ return fPng_ptr; }

◆ processData()

bool SkPngCodec::processData ( )

protected

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.

Definition at line 213 of file SkPngCodec.cpp.

                             {
    switch (setjmp(PNG_JMPBUF(fPng_ptr))) {
        case kPngError:
            // There was an error. Stop processing data.
            // FIXME: Do we need to discard png_ptr?
            return false;
        case kStopDecoding:
            // We decoded all the lines we want.
            return true;
        case kSetJmpOkay:
            // Everything is okay.
            break;
        default:
            // No other values should be passed to longjmp.
            SkASSERT(false);
    }
 
    // Arbitrary buffer size
    constexpr size_t kBufferSize = 4096;
    char buffer[kBufferSize];
 
    bool iend = false;
    while (true) {
        size_t length;
        if (fDecodedIdat) {
            // Parse chunk length and type.
            if (this->stream()->read(buffer, 8) < 8) {
                break;
            }
 
            png_byte* chunk = reinterpret_cast<png_byte*>(buffer);
            png_process_data(fPng_ptr, fInfo_ptr, chunk, 8);
            if (is_chunk(chunk, "IEND")) {
                iend = true;
            }
 
            length = png_get_uint_32(chunk);
        } else {
            length = fIdatLength;
            png_byte idat[] = {0, 0, 0, 0, 'I', 'D', 'A', 'T'};
            png_save_uint_32(idat, length);
            png_process_data(fPng_ptr, fInfo_ptr, idat, 8);
            fDecodedIdat = true;
        }
 
        // Process the full chunk + CRC.
        if (!process_data(fPng_ptr, fInfo_ptr, this->stream(), buffer, kBufferSize, length + 4)
                || iend) {
            break;
        }
    }
 
    return true;
}

◆ setIdatLength()

void SkPngCodec::setIdatLength ( size_t len )

inline

Definition at line 36 of file SkPngCodec.h.

36{ fIdatLength = len; }

gn.find_headers.len

len

Definition: find_headers.py:30

◆ setRange()

virtual void SkPngCodec::setRange	(	int	firstRow,
		int	lastRow,
		void *	dst,
		size_t	rowBytes
	)

privatepure virtual

◆ swizzler()

SkSwizzler * SkPngCodec::swizzler ( )

inlineprotected

Definition at line 68 of file SkPngCodec.h.

68{ return fSwizzler.get(); }

Member Data Documentation

◆ fBitDepth

const int SkPngCodec::fBitDepth

protected

Definition at line 94 of file SkPngCodec.h.

◆ fColorTable

sk_sp<SkColorPalette> SkPngCodec::fColorTable

protected

Definition at line 90 of file SkPngCodec.h.

◆ fColorXformSrcRow

void* SkPngCodec::fColorXformSrcRow

protected

Definition at line 93 of file SkPngCodec.h.

◆ fInfo_ptr

voidp SkPngCodec::fInfo_ptr

protected

Definition at line 87 of file SkPngCodec.h.

◆ fPng_ptr

voidp SkPngCodec::fPng_ptr

protected

Definition at line 86 of file SkPngCodec.h.

◆ fPngChunkReader

sk_sp<SkPngChunkReader> SkPngCodec::fPngChunkReader

protected

Definition at line 85 of file SkPngCodec.h.

◆ fStorage

skia_private::AutoTMalloc<uint8_t> SkPngCodec::fStorage

protected

Definition at line 92 of file SkPngCodec.h.

◆ fSwizzler

std::unique_ptr<SkSwizzler> SkPngCodec::fSwizzler

protected

Definition at line 91 of file SkPngCodec.h.

The documentation for this class was generated from the following files:

third_party/skia/src/codec/SkPngCodec.h
third_party/skia/src/codec/SkPngCodec.cpp

Classes

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Private Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ ~SkPngCodec()

◆ SkPngCodec()

Member Function Documentation

◆ applyXformRow()

◆ decode()

◆ decodeAllRows()

◆ getSampler()

◆ info_ptr()

◆ initializeXformParams()

◆ IsPng()

◆ MakeFromStream()

◆ onGetEncodedFormat()

◆ onGetPixels()

◆ onIncrementalDecode()

◆ onRewind()

◆ onStartIncrementalDecode()

◆ png_ptr()

◆ processData()

◆ setIdatLength()

◆ setRange()

◆ swizzler()

Member Data Documentation

◆ fBitDepth

◆ fColorTable

◆ fColorXformSrcRow

◆ fInfo_ptr

◆ fPng_ptr

◆ fPngChunkReader

◆ fStorage

◆ fSwizzler