#include <SkWebpCodec.h>

Inheritance diagram for SkWebpCodec:

Static Public Member Functions
static std::unique_ptr< SkCodec >	MakeFromStream (std::unique_ptr< SkStream >, Result *)

static bool	IsWebp (const void *, size_t)

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
Result	onGetPixels (const SkImageInfo &, void , size_t, const Options &, int ) override

SkEncodedImageFormat	onGetEncodedFormat () const override

bool	onGetValidSubset (SkIRect *) const override

int	onGetFrameCount () override

bool	onGetFrameInfo (int, FrameInfo *) const override

int	onGetRepetitionCount () override

const SkFrameHolder *	getFrameHolder () const override

Protected Member Functions inherited from SkScalingCodec
	SkScalingCodec (SkEncodedInfo &&info, XformFormat srcFormat, std::unique_ptr< SkStream > stream, SkEncodedOrigin origin=kTopLeft_SkEncodedOrigin)

SkISize	onGetScaledDimensions (float desiredScale) const override

bool	onDimensionsSupported (const SkISize &requested) 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 ()

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 }

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 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 35 of file SkWebpCodec.h.

Member Function Documentation

◆ getFrameHolder()

const SkFrameHolder * SkWebpCodec::getFrameHolder ( ) const

inlineoverrideprotectedvirtual

For multi-framed images, return the object with information about the frames.

Reimplemented from SkCodec.

Definition at line 50 of file SkWebpCodec.h.

                                                         {
        return &fFrameHolder;
    }

◆ IsWebp()

bool SkWebpCodec::IsWebp	(	const void *	buf,
		size_t	bytesRead
	)

static

Definition at line 50 of file SkWebpCodec.cpp.

                                                          {
    // WEBP starts with the following:
    // RIFFXXXXWEBPVP
    // Where XXXX is unspecified.
    const char* bytes = static_cast<const char*>(buf);
    return bytesRead >= 14 && !memcmp(bytes, "RIFF", 4) && !memcmp(&bytes[8], "WEBPVP", 6);
}

◆ MakeFromStream()

std::unique_ptr< SkCodec > SkWebpCodec::MakeFromStream	(	std::unique_ptr< SkStream >	stream,
		Result *	result
	)

static

Definition at line 60 of file SkWebpCodec.cpp.

                                                                     {
    SkASSERT(result);
    if (!stream) {
        *result = SkCodec::kInvalidInput;
        return nullptr;
    }
    // Webp demux needs a contiguous data buffer.
    sk_sp<SkData> data = nullptr;
    if (stream->getMemoryBase()) {
        // It is safe to make without copy because we'll hold onto the stream.
        data = SkData::MakeWithoutCopy(stream->getMemoryBase(), stream->getLength());
    } else {
        data = SkCopyStreamToData(stream.get());
 
        // If we are forced to copy the stream to a data, we can go ahead and delete the stream.
        stream.reset(nullptr);
    }
 
    // It's a little strange that the |demux| will outlive |webpData|, though it needs the
    // pointer in |webpData| to remain valid.  This works because the pointer remains valid
    // until the SkData is freed.
    WebPData webpData = { data->bytes(), data->size() };
    WebPDemuxState state;
    SkAutoTCallVProc<WebPDemuxer, WebPDemuxDelete> demux(WebPDemuxPartial(&webpData, &state));
    switch (state) {
        case WEBP_DEMUX_PARSE_ERROR:
            *result = kInvalidInput;
            return nullptr;
        case WEBP_DEMUX_PARSING_HEADER:
            *result = kIncompleteInput;
            return nullptr;
        case WEBP_DEMUX_PARSED_HEADER:
        case WEBP_DEMUX_DONE:
            SkASSERT(demux);
            break;
    }
 
    const int width = WebPDemuxGetI(demux, WEBP_FF_CANVAS_WIDTH);
    const int height = WebPDemuxGetI(demux, WEBP_FF_CANVAS_HEIGHT);
 
    // Validate the image size that's about to be decoded.
    {
        const int64_t size = sk_64_mul(width, height);
        // now check that if we are 4-bytes per pixel, we also don't overflow
        if (!SkTFitsIn<int32_t>(size) || SkTo<int32_t>(size) > (0x7FFFFFFF >> 2)) {
            *result = kInvalidInput;
            return nullptr;
        }
    }
 
    std::unique_ptr<SkEncodedInfo::ICCProfile> profile = nullptr;
    {
        WebPChunkIterator chunkIterator;
        SkAutoTCallVProc<WebPChunkIterator, WebPDemuxReleaseChunkIterator> autoCI(&chunkIterator);
        if (WebPDemuxGetChunk(demux, "ICCP", 1, &chunkIterator)) {
            // FIXME: I think this could be MakeWithoutCopy
            auto chunk = SkData::MakeWithCopy(chunkIterator.chunk.bytes, chunkIterator.chunk.size);
            profile = SkEncodedInfo::ICCProfile::Make(std::move(chunk));
        }
        if (profile && profile->profile()->data_color_space != skcms_Signature_RGB) {
            profile = nullptr;
        }
    }
 
    SkEncodedOrigin origin = kDefault_SkEncodedOrigin;
    {
        WebPChunkIterator chunkIterator;
        SkAutoTCallVProc<WebPChunkIterator, WebPDemuxReleaseChunkIterator> autoCI(&chunkIterator);
        if (WebPDemuxGetChunk(demux, "EXIF", 1, &chunkIterator)) {
            SkParseEncodedOrigin(chunkIterator.chunk.bytes, chunkIterator.chunk.size, &origin);
        }
    }
 
    // Get the first frame and its "features" to determine the color and alpha types.
    WebPIterator frame;
    SkAutoTCallVProc<WebPIterator, WebPDemuxReleaseIterator> autoFrame(&frame);
    if (!WebPDemuxGetFrame(demux, 1, &frame)) {
        *result = kIncompleteInput;
        return nullptr;
    }
 
    WebPBitstreamFeatures features;
    switch (WebPGetFeatures(frame.fragment.bytes, frame.fragment.size, &features)) {
        case VP8_STATUS_OK:
            break;
        case VP8_STATUS_SUSPENDED:
        case VP8_STATUS_NOT_ENOUGH_DATA:
            *result = kIncompleteInput;
            return nullptr;
        default:
            *result = kInvalidInput;
            return nullptr;
    }
 
    const bool hasAlpha = SkToBool(frame.has_alpha)
            || frame.width != width || frame.height != height;
    SkEncodedInfo::Color color;
    SkEncodedInfo::Alpha alpha;
    switch (features.format) {
        case 0:
            // This indicates a "mixed" format.  We could see this for
            // animated webps (multiple fragments).
            // We could also guess kYUV here, but I think it makes more
            // sense to guess kBGRA which is likely closer to the final
            // output.  Otherwise, we might end up converting
            // BGRA->YUVA->BGRA.
            [[fallthrough]];
        case 2:
            // This is the lossless format (BGRA).
            if (hasAlpha) {
                color = SkEncodedInfo::kBGRA_Color;
                alpha = SkEncodedInfo::kUnpremul_Alpha;
            } else {
                color = SkEncodedInfo::kBGRX_Color;
                alpha = SkEncodedInfo::kOpaque_Alpha;
            }
            break;
        case 1:
            // This is the lossy format (YUV).
            if (hasAlpha) {
                color = SkEncodedInfo::kYUVA_Color;
                alpha = SkEncodedInfo::kUnpremul_Alpha;
            } else {
                color = SkEncodedInfo::kYUV_Color;
                alpha = SkEncodedInfo::kOpaque_Alpha;
            }
            break;
        default:
            *result = kInvalidInput;
            return nullptr;
    }
 
 
    *result = kSuccess;
    SkEncodedInfo info = SkEncodedInfo::Make(width, height, color, alpha, 8, std::move(profile));
    return std::unique_ptr<SkCodec>(new SkWebpCodec(std::move(info), std::move(stream),
                                                    demux.release(), std::move(data), origin));
}

◆ onGetEncodedFormat()

SkEncodedImageFormat SkWebpCodec::onGetEncodedFormat ( ) const

inlineoverrideprotectedvirtual

Implements SkCodec.

Definition at line 42 of file SkWebpCodec.h.

42{ return SkEncodedImageFormat::kWEBP; }

SkEncodedImageFormat::kWEBP

@ kWEBP

◆ onGetFrameCount()

int SkWebpCodec::onGetFrameCount ( )

overrideprotectedvirtual

Reimplemented from SkCodec.

Definition at line 252 of file SkWebpCodec.cpp.

                                 {
    auto flags = WebPDemuxGetI(fDemux.get(), WEBP_FF_FORMAT_FLAGS);
    if (!(flags & ANIMATION_FLAG)) {
        return 1;
    }
 
    const uint32_t oldFrameCount = fFrameHolder.size();
    if (fFailed) {
        return oldFrameCount;
    }
 
    const uint32_t frameCount = WebPDemuxGetI(fDemux, WEBP_FF_FRAME_COUNT);
    if (oldFrameCount == frameCount) {
        // We have already parsed this.
        return frameCount;
    }
 
    fFrameHolder.reserve(frameCount);
 
    for (uint32_t i = oldFrameCount; i < frameCount; i++) {
        WebPIterator iter;
        SkAutoTCallVProc<WebPIterator, WebPDemuxReleaseIterator> autoIter(&iter);
 
        if (!WebPDemuxGetFrame(fDemux.get(), i + 1, &iter)) {
            fFailed = true;
            break;
        }
 
        // libwebp only reports complete frames of an animated image.
        SkASSERT(iter.complete);
 
        Frame* frame = fFrameHolder.appendNewFrame(iter.has_alpha);
        frame->setXYWH(iter.x_offset, iter.y_offset, iter.width, iter.height);
        frame->setDisposalMethod(iter.dispose_method == WEBP_MUX_DISPOSE_BACKGROUND ?
                SkCodecAnimation::DisposalMethod::kRestoreBGColor :
                SkCodecAnimation::DisposalMethod::kKeep);
        frame->setDuration(iter.duration);
        if (WEBP_MUX_BLEND != iter.blend_method) {
            frame->setBlend(SkCodecAnimation::Blend::kSrc);
        }
        fFrameHolder.setAlphaAndRequiredFrame(frame);
    }
 
    return fFrameHolder.size();
 
}

◆ onGetFrameInfo()

bool SkWebpCodec::onGetFrameInfo	(	int	i,
		FrameInfo *	frameInfo
	)		const

overrideprotectedvirtual

Reimplemented from SkCodec.

Definition at line 308 of file SkWebpCodec.cpp.

                                                                  {
    if (i >= fFrameHolder.size()) {
        return false;
    }
 
    const Frame* frame = fFrameHolder.frame(i);
    if (!frame) {
        return false;
    }
 
    if (frameInfo) {
        // libwebp only reports fully received frames for an
        // animated image.
        frame->fillIn(frameInfo, true);
    }
 
    return true;
}

◆ onGetPixels()

SkCodec::Result SkWebpCodec::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 368 of file SkWebpCodec.cpp.

                                                                                      {
    const int index = options.fFrameIndex;
    SkASSERT(0 == index || index < fFrameHolder.size());
    SkASSERT(0 == index || !options.fSubset);
 
    WebPDecoderConfig config;
    if (0 == WebPInitDecoderConfig(&config)) {
        // ABI mismatch.
        // FIXME: New enum for this?
        return kInvalidInput;
    }
 
    // Free any memory associated with the buffer. Must be called last, so we declare it first.
    SkAutoTCallVProc<WebPDecBuffer, WebPFreeDecBuffer> autoFree(&(config.output));
 
    WebPIterator frame;
    SkAutoTCallVProc<WebPIterator, WebPDemuxReleaseIterator> autoFrame(&frame);
    // If this succeeded in onGetFrameCount(), it should succeed again here.
    SkAssertResult(WebPDemuxGetFrame(fDemux, index + 1, &frame));
 
    const bool independent = index == 0 ? true :
            (fFrameHolder.frame(index)->getRequiredFrame() == kNoFrame);
    // Get the frameRect.  libwebp will have already signaled an error if this is not fully
    // contained by the canvas.
    auto frameRect = SkIRect::MakeXYWH(frame.x_offset, frame.y_offset, frame.width, frame.height);
    SkASSERT(this->bounds().contains(frameRect));
    const bool frameIsSubset = frameRect != this->bounds();
    if (independent && frameIsSubset) {
        SkSampler::Fill(dstInfo, dst, rowBytes, options.fZeroInitialized);
    }
 
    int dstX = frameRect.x();
    int dstY = frameRect.y();
    int subsetWidth = frameRect.width();
    int subsetHeight = frameRect.height();
    if (options.fSubset) {
        SkIRect subset = *options.fSubset;
        SkASSERT(this->bounds().contains(subset));
        SkASSERT(SkIsAlign2(subset.fLeft) && SkIsAlign2(subset.fTop));
        SkASSERT(this->getValidSubset(&subset) && subset == *options.fSubset);
 
        if (!SkIRect::Intersects(subset, frameRect)) {
            return kSuccess;
        }
 
        int minXOffset = std::min(dstX, subset.x());
        int minYOffset = std::min(dstY, subset.y());
        dstX -= minXOffset;
        dstY -= minYOffset;
        frameRect.offset(-minXOffset, -minYOffset);
        subset.offset(-minXOffset, -minYOffset);
 
        // Just like we require that the requested subset x and y offset are even, libwebp
        // guarantees that the frame x and y offset are even (it's actually impossible to specify
        // an odd frame offset).  So we can still guarantee that the adjusted offsets are even.
        SkASSERT(SkIsAlign2(subset.fLeft) && SkIsAlign2(subset.fTop));
 
        SkIRect intersection;
        SkAssertResult(intersection.intersect(frameRect, subset));
        subsetWidth = intersection.width();
        subsetHeight = intersection.height();
 
        config.options.use_cropping = 1;
        config.options.crop_left = subset.x();
        config.options.crop_top = subset.y();
        config.options.crop_width = subsetWidth;
        config.options.crop_height = subsetHeight;
    }
 
    // Ignore the frame size and offset when determining if scaling is necessary.
    int scaledWidth = subsetWidth;
    int scaledHeight = subsetHeight;
    SkISize srcSize = options.fSubset ? options.fSubset->size() : this->dimensions();
    if (srcSize != dstInfo.dimensions()) {
        config.options.use_scaling = 1;
 
        if (frameIsSubset) {
            float scaleX = ((float) dstInfo.width()) / srcSize.width();
            float scaleY = ((float) dstInfo.height()) / srcSize.height();
 
            // We need to be conservative here and floor rather than round.
            // Otherwise, we may find ourselves decoding off the end of memory.
            dstX = scaleX * dstX;
            scaledWidth = scaleX * scaledWidth;
            dstY = scaleY * dstY;
            scaledHeight = scaleY * scaledHeight;
            if (0 == scaledWidth || 0 == scaledHeight) {
                return kSuccess;
            }
        } else {
            scaledWidth = dstInfo.width();
            scaledHeight = dstInfo.height();
        }
 
        config.options.scaled_width = scaledWidth;
        config.options.scaled_height = scaledHeight;
    }
 
    const bool blendWithPrevFrame = !independent && frame.blend_method == WEBP_MUX_BLEND
        && frame.has_alpha;
 
    auto webpInfo = dstInfo;
    if (!frame.has_alpha) {
        webpInfo = webpInfo.makeAlphaType(kOpaque_SkAlphaType);
    } else if (this->colorXform() || blendWithPrevFrame) {
        // the colorXform and blend_line expect unpremul.
        webpInfo = webpInfo.makeAlphaType(kUnpremul_SkAlphaType);
    }
    if (this->colorXform()) {
        // Swizzling between RGBA and BGRA is zero cost in a color transform.  So when we have a
        // color transform, we should decode to whatever is easiest for libwebp, and then let the
        // color transform swizzle if necessary.
        // Lossy webp is encoded as YUV (so RGBA and BGRA are the same cost).  Lossless webp is
        // encoded as BGRA. This means decoding to BGRA is either faster or the same cost as RGBA.
        webpInfo = webpInfo.makeColorType(kBGRA_8888_SkColorType);
    }
 
    SkBitmap webpDst;
    if ((this->colorXform() && !is_8888(dstInfo.colorType())) || blendWithPrevFrame) {
        // We will decode the entire image and then perform the color transform.  libwebp
        // does not provide a row-by-row API.  This is a shame particularly when we do not want
        // 8888, since we will need to create another image sized buffer.
        webpDst.allocPixels(webpInfo);
    } else {
        // libwebp can decode directly into the output memory.
        webpDst.installPixels(webpInfo, dst, rowBytes);
    }
 
    config.output.colorspace = webp_decode_mode(webpInfo.colorType(),
            webpInfo.alphaType() == kPremul_SkAlphaType);
    config.output.is_external_memory = 1;
 
    config.output.u.RGBA.rgba = reinterpret_cast<uint8_t*>(webpDst.getAddr(dstX, dstY));
    config.output.u.RGBA.stride = static_cast<int>(webpDst.rowBytes());
    config.output.u.RGBA.size = webpDst.computeByteSize();
 
    SkAutoTCallVProc<WebPIDecoder, WebPIDelete> idec(WebPIDecode(nullptr, 0, &config));
    if (!idec) {
        return kInvalidInput;
    }
 
    int rowsDecoded = 0;
    SkCodec::Result result;
    switch (WebPIUpdate(idec, frame.fragment.bytes, frame.fragment.size)) {
        case VP8_STATUS_OK:
            rowsDecoded = scaledHeight;
            result = kSuccess;
            break;
        case VP8_STATUS_SUSPENDED:
            if (!WebPIDecGetRGB(idec, &rowsDecoded, nullptr, nullptr, nullptr)
                    || rowsDecoded <= 0) {
                return kInvalidInput;
            }
            *rowsDecodedPtr = rowsDecoded + dstY;
            result = kIncompleteInput;
            break;
        default:
            return kInvalidInput;
    }
 
    const size_t dstBpp = dstInfo.bytesPerPixel();
    dst = SkTAddOffset<void>(dst, dstBpp * dstX + rowBytes * dstY);
    const size_t srcRowBytes = config.output.u.RGBA.stride;
 
    const auto dstCT = dstInfo.colorType();
    if (this->colorXform()) {
        uint32_t* xformSrc = (uint32_t*) config.output.u.RGBA.rgba;
        SkBitmap tmp;
        void* xformDst;
 
        if (blendWithPrevFrame) {
            // Xform into temporary bitmap big enough for one row.
            tmp.allocPixels(dstInfo.makeWH(scaledWidth, 1));
            xformDst = tmp.getPixels();
        } else {
            xformDst = dst;
        }
 
        for (int y = 0; y < rowsDecoded; y++) {
            this->applyColorXform(xformDst, xformSrc, scaledWidth);
            if (blendWithPrevFrame) {
                blend_line(dstCT, dst, dstCT, xformDst,
                        dstInfo.alphaType(), frame.has_alpha, scaledWidth);
                dst = SkTAddOffset<void>(dst, rowBytes);
            } else {
                xformDst = SkTAddOffset<void>(xformDst, rowBytes);
            }
            xformSrc = SkTAddOffset<uint32_t>(xformSrc, srcRowBytes);
        }
    } else if (blendWithPrevFrame) {
        const uint8_t* src = config.output.u.RGBA.rgba;
 
        for (int y = 0; y < rowsDecoded; y++) {
            blend_line(dstCT, dst, webpDst.colorType(), src,
                    dstInfo.alphaType(), frame.has_alpha, scaledWidth);
            src = SkTAddOffset<const uint8_t>(src, srcRowBytes);
            dst = SkTAddOffset<void>(dst, rowBytes);
        }
    }
 
    return result;
}

◆ onGetRepetitionCount()

int SkWebpCodec::onGetRepetitionCount ( )

overrideprotectedvirtual

Reimplemented from SkCodec.

Definition at line 237 of file SkWebpCodec.cpp.

                                      {
    auto flags = WebPDemuxGetI(fDemux.get(), WEBP_FF_FORMAT_FLAGS);
    if (!(flags & ANIMATION_FLAG)) {
        return 0;
    }
 
    int loopCount = WebPDemuxGetI(fDemux.get(), WEBP_FF_LOOP_COUNT);
    if (0 == loopCount) {
        return kRepetitionCountInfinite;
    }
 
    loopCount--;
    return loopCount;
}

◆ onGetValidSubset()

bool SkWebpCodec::onGetValidSubset ( SkIRect * desiredSubset ) const

overrideprotectedvirtual

Reimplemented from SkCodec.

Definition at line 220 of file SkWebpCodec.cpp.

                                                               {
    if (!desiredSubset) {
        return false;
    }
 
    if (!this->bounds().contains(*desiredSubset)) {
        return false;
    }
 
    // As stated below, libwebp snaps to even left and top. Make sure top and left are even, so we
    // decode this exact subset.
    // Leave right and bottom unmodified, so we suggest a slightly larger subset than requested.
    desiredSubset->fLeft = (desiredSubset->fLeft >> 1) << 1;
    desiredSubset->fTop = (desiredSubset->fTop >> 1) << 1;
    return true;
}

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

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

Static Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ getFrameHolder()

◆ IsWebp()

◆ MakeFromStream()

◆ onGetEncodedFormat()

◆ onGetFrameCount()

◆ onGetFrameInfo()

◆ onGetPixels()

◆ onGetRepetitionCount()

◆ onGetValidSubset()