bool WEBPImageDecoder::updateDemuxer()
{
if (failed())
return false;
if (m_haveAlreadyParsedThisData)
return true;
m_haveAlreadyParsedThisData = true;
const unsigned webpHeaderSize = 30;
if (m_data->size() < webpHeaderSize)
return false; // Await VP8X header so WebPDemuxPartial succeeds.
WebPDemuxDelete(m_demux);
WebPData inputData = { reinterpret_cast<const uint8_t*>(m_data->data()), m_data->size() };
m_demux = WebPDemuxPartial(&inputData, &m_demuxState);
if (!m_demux || (isAllDataReceived() && m_demuxState != WEBP_DEMUX_DONE))
return setFailed();
ASSERT(m_demuxState > WEBP_DEMUX_PARSING_HEADER);
if (!WebPDemuxGetI(m_demux, WEBP_FF_FRAME_COUNT))
return false; // Wait until the encoded image frame data arrives.
if (!isDecodedSizeAvailable()) {
int width = WebPDemuxGetI(m_demux, WEBP_FF_CANVAS_WIDTH);
int height = WebPDemuxGetI(m_demux, WEBP_FF_CANVAS_HEIGHT);
if (!setSize(width, height))
return setFailed();
m_formatFlags = WebPDemuxGetI(m_demux, WEBP_FF_FORMAT_FLAGS);
if (!(m_formatFlags & ANIMATION_FLAG)) {
m_repetitionCount = cAnimationNone;
} else {
// Since we have parsed at least one frame, even if partially,
// the global animation (ANIM) properties have been read since
// an ANIM chunk must precede the ANMF frame chunks.
m_repetitionCount = WebPDemuxGetI(m_demux, WEBP_FF_LOOP_COUNT);
// Repetition count is always <= 16 bits.
ASSERT(m_repetitionCount == (m_repetitionCount & 0xffff));
// Repetition count is the number of animation cycles to show,
// where 0 means "infinite". But ImageSource::repetitionCount()
// returns -1 for "infinite", and 0 and up for "show the image
// animation one cycle more than the value". Subtract one here
// to correctly handle the finite and infinite cases.
--m_repetitionCount;
// FIXME: Implement ICC profile support for animated images.
m_formatFlags &= ~ICCP_FLAG;
}
#if USE(QCMSLIB)
if ((m_formatFlags & ICCP_FLAG) && !ignoresGammaAndColorProfile())
readColorProfile();
#endif
}
ASSERT(isDecodedSizeAvailable());
return true;
}
bool WEBPImageDecoder::decode(bool onlySize)
{
if (failed())
return false;
const uint8_t* dataBytes = reinterpret_cast<const uint8_t*>(m_data->data());
const size_t dataSize = m_data->size();
if (!ImageDecoder::isSizeAvailable()) {
static const size_t imageHeaderSize = 30;
if (dataSize < imageHeaderSize)
return false;
int width, height;
#ifdef QCMS_WEBP_COLOR_CORRECTION
WebPData inputData = { dataBytes, dataSize };
WebPDemuxState state;
WebPDemuxer* demuxer = WebPDemuxPartial(&inputData, &state);
if (!demuxer)
return setFailed();
width = WebPDemuxGetI(demuxer, WEBP_FF_CANVAS_WIDTH);
height = WebPDemuxGetI(demuxer, WEBP_FF_CANVAS_HEIGHT);
m_formatFlags = WebPDemuxGetI(demuxer, WEBP_FF_FORMAT_FLAGS);
m_hasAlpha = !!(m_formatFlags & ALPHA_FLAG);
WebPDemuxDelete(demuxer);
if (state <= WEBP_DEMUX_PARSING_HEADER)
return false;
#elif (WEBP_DECODER_ABI_VERSION >= 0x0163)
WebPBitstreamFeatures features;
if (WebPGetFeatures(dataBytes, dataSize, &features) != VP8_STATUS_OK)
return setFailed();
width = features.width;
height = features.height;
m_hasAlpha = features.has_alpha;
#else
// Earlier version won't be able to display WebP files with alpha.
if (!WebPGetInfo(dataBytes, dataSize, &width, &height))
return setFailed();
m_hasAlpha = false;
#endif
if (!setSize(width, height))
return setFailed();
}
ASSERT(ImageDecoder::isSizeAvailable());
if (onlySize)
return true;
ASSERT(!m_frameBufferCache.isEmpty());
ImageFrame& buffer = m_frameBufferCache[0];
ASSERT(buffer.status() != ImageFrame::FrameComplete);
if (buffer.status() == ImageFrame::FrameEmpty) {
if (!buffer.setSize(size().width(), size().height()))
return setFailed();
buffer.setStatus(ImageFrame::FramePartial);
buffer.setHasAlpha(m_hasAlpha);
buffer.setOriginalFrameRect(IntRect(IntPoint(), size()));
}
if (!m_decoder) {
WEBP_CSP_MODE mode = outputMode(m_hasAlpha);
if (!m_premultiplyAlpha)
mode = outputMode(false);
if ((m_formatFlags & ICCP_FLAG) && !ignoresGammaAndColorProfile())
mode = MODE_RGBA; // Decode to RGBA for input to libqcms.
int rowStride = size().width() * sizeof(ImageFrame::PixelData);
uint8_t* output = reinterpret_cast<uint8_t*>(buffer.getAddr(0, 0));
int outputSize = size().height() * rowStride;
m_decoder = WebPINewRGB(mode, output, outputSize, rowStride);
if (!m_decoder)
return setFailed();
}
switch (WebPIUpdate(m_decoder, dataBytes, dataSize)) {
case VP8_STATUS_OK:
if ((m_formatFlags & ICCP_FLAG) && !ignoresGammaAndColorProfile())
applyColorProfile(dataBytes, dataSize, buffer);
buffer.setStatus(ImageFrame::FrameComplete);
clear();
return true;
case VP8_STATUS_SUSPENDED:
if ((m_formatFlags & ICCP_FLAG) && !ignoresGammaAndColorProfile())
applyColorProfile(dataBytes, dataSize, buffer);
return false;
default:
clear();
return setFailed();
}
}
void WEBPImageDecoder::applyPostProcessing(size_t frameIndex)
{
ImageFrame& buffer = m_frameBufferCache[frameIndex];
int width;
int decodedHeight;
if (!WebPIDecGetRGB(m_decoder, &decodedHeight, &width, 0, 0))
return; // See also https://bugs.webkit.org/show_bug.cgi?id=74062
if (decodedHeight <= 0)
return;
const IntRect& frameRect = buffer.originalFrameRect();
ASSERT_WITH_SECURITY_IMPLICATION(width == frameRect.width());
ASSERT_WITH_SECURITY_IMPLICATION(decodedHeight <= frameRect.height());
const int left = frameRect.x();
const int top = frameRect.y();
#if USE(QCMSLIB)
if ((m_formatFlags & ICCP_FLAG) && !ignoresGammaAndColorProfile()) {
if (!m_haveReadProfile) {
readColorProfile();
m_haveReadProfile = true;
}
for (int y = m_decodedHeight; y < decodedHeight; ++y) {
const int canvasY = top + y;
uint8_t* row = reinterpret_cast<uint8_t*>(buffer.getAddr(left, canvasY));
if (qcms_transform* transform = colorTransform())
qcms_transform_data_type(transform, row, row, width, QCMS_OUTPUT_RGBX);
uint8_t* pixel = row;
for (int x = 0; x < width; ++x, pixel += 4) {
const int canvasX = left + x;
buffer.setRGBA(canvasX, canvasY, pixel[0], pixel[1], pixel[2], pixel[3]);
}
}
}
#endif // USE(QCMSLIB)
// During the decoding of current frame, we may have set some pixels to be transparent (i.e. alpha < 255).
// However, the value of each of these pixels should have been determined by blending it against the value
// of that pixel in the previous frame if alpha blend source was 'BlendAtopPreviousFrame'. So, we correct these
// pixels based on disposal method of the previous frame and the previous frame buffer.
// FIXME: This could be avoided if libwebp decoder had an API that used the previous required frame
// to do the alpha-blending by itself.
if ((m_formatFlags & ANIMATION_FLAG) && frameIndex && buffer.alphaBlendSource() == ImageFrame::BlendAtopPreviousFrame && buffer.requiredPreviousFrameIndex() != kNotFound) {
ImageFrame& prevBuffer = m_frameBufferCache[frameIndex - 1];
ASSERT(prevBuffer.status() == ImageFrame::FrameComplete);
ImageFrame::DisposalMethod prevDisposalMethod = prevBuffer.disposalMethod();
if (prevDisposalMethod == ImageFrame::DisposeKeep) { // Blend transparent pixels with pixels in previous canvas.
for (int y = m_decodedHeight; y < decodedHeight; ++y) {
m_blendFunction(buffer, prevBuffer, top + y, left, width);
}
} else if (prevDisposalMethod == ImageFrame::DisposeOverwriteBgcolor) {
const IntRect& prevRect = prevBuffer.originalFrameRect();
// We need to blend a transparent pixel with its value just after initFrame() call. That is:
// * Blend with fully transparent pixel if it belongs to prevRect <-- This is a no-op.
// * Blend with the pixel in the previous canvas otherwise <-- Needs alpha-blending.
for (int y = m_decodedHeight; y < decodedHeight; ++y) {
int canvasY = top + y;
int left1, width1, left2, width2;
findBlendRangeAtRow(frameRect, prevRect, canvasY, left1, width1, left2, width2);
if (width1 > 0)
m_blendFunction(buffer, prevBuffer, canvasY, left1, width1);
if (width2 > 0)
m_blendFunction(buffer, prevBuffer, canvasY, left2, width2);
}
}
}
m_decodedHeight = decodedHeight;
buffer.setPixelsChanged(true);
}
bool WEBPImageDecoder::decode(const uint8_t* dataBytes, size_t dataSize, bool onlySize, size_t frameIndex)
{
if (failed())
return false;
if (!ImageDecoder::isSizeAvailable()) {
static const size_t imageHeaderSize = 30;
if (dataSize < imageHeaderSize)
return false;
int width, height;
WebPBitstreamFeatures features;
if (WebPGetFeatures(dataBytes, dataSize, &features) != VP8_STATUS_OK)
return setFailed();
width = features.width;
height = features.height;
m_formatFlags = features.has_alpha ? ALPHA_FLAG : 0;
if (!setSize(width, height))
return setFailed();
}
ASSERT(ImageDecoder::isSizeAvailable());
if (onlySize)
return true;
ASSERT(m_frameBufferCache.size() > frameIndex);
ImageFrame& buffer = m_frameBufferCache[frameIndex];
ASSERT(buffer.status() != ImageFrame::FrameComplete);
if (buffer.status() == ImageFrame::FrameEmpty) {
if (!buffer.setSize(size().width(), size().height()))
return setFailed();
buffer.setStatus(ImageFrame::FramePartial);
// The buffer is transparent outside the decoded area while the image is loading.
// The correct value of 'hasAlpha' for the frame will be set when it is fully decoded.
buffer.setHasAlpha(true);
buffer.setOriginalFrameRect(IntRect(IntPoint(), size()));
}
const IntRect& frameRect = buffer.originalFrameRect();
if (!m_decoder) {
WEBP_CSP_MODE mode = outputMode(m_formatFlags & ALPHA_FLAG);
if (!m_premultiplyAlpha)
mode = outputMode(false);
#if USE(QCMSLIB)
if ((m_formatFlags & ICCP_FLAG) && !ignoresGammaAndColorProfile())
mode = MODE_RGBA; // Decode to RGBA for input to libqcms.
#endif
WebPInitDecBuffer(&m_decoderBuffer);
m_decoderBuffer.colorspace = mode;
m_decoderBuffer.u.RGBA.stride = size().width() * sizeof(ImageFrame::PixelData);
m_decoderBuffer.u.RGBA.size = m_decoderBuffer.u.RGBA.stride * frameRect.height();
m_decoderBuffer.is_external_memory = 1;
m_decoder = WebPINewDecoder(&m_decoderBuffer);
if (!m_decoder)
return setFailed();
}
m_decoderBuffer.u.RGBA.rgba = reinterpret_cast<uint8_t*>(buffer.getAddr(frameRect.x(), frameRect.y()));
switch (WebPIUpdate(m_decoder, dataBytes, dataSize)) {
case VP8_STATUS_OK:
applyPostProcessing(frameIndex);
buffer.setHasAlpha((m_formatFlags & ALPHA_FLAG) || m_frameBackgroundHasAlpha);
buffer.setStatus(ImageFrame::FrameComplete);
clearDecoder();
return true;
case VP8_STATUS_SUSPENDED:
if (!isAllDataReceived() && !frameIsCompleteAtIndex(frameIndex)) {
applyPostProcessing(frameIndex);
return false;
}
// FALLTHROUGH
default:
clear();
return setFailed();
}
}
bool WEBPImageDecoder::updateDemuxer()
{
if (failed())
return false;
if (m_haveAlreadyParsedThisData)
return true;
m_haveAlreadyParsedThisData = true;
const unsigned webpHeaderSize = 20;
if (m_data->size() < webpHeaderSize)
return false; // Wait for headers so that WebPDemuxPartial doesn't return null.
WebPDemuxDelete(m_demux);
WebPData inputData = { reinterpret_cast<const uint8_t*>(m_data->data()), m_data->size() };
m_demux = WebPDemuxPartial(&inputData, &m_demuxState);
if (!m_demux || (isAllDataReceived() && m_demuxState != WEBP_DEMUX_DONE))
return setFailed();
if (m_demuxState <= WEBP_DEMUX_PARSING_HEADER)
return false; // Not enough data for parsing canvas width/height yet.
bool hasAnimation = (m_formatFlags & ANIMATION_FLAG);
if (!ImageDecoder::isSizeAvailable()) {
m_formatFlags = WebPDemuxGetI(m_demux, WEBP_FF_FORMAT_FLAGS);
hasAnimation = (m_formatFlags & ANIMATION_FLAG);
if (!hasAnimation)
m_repetitionCount = cAnimationNone;
else
m_formatFlags &= ~ICCP_FLAG; // FIXME: Implement ICC profile support for animated images.
#if USE(QCMSLIB)
if ((m_formatFlags & ICCP_FLAG) && !ignoresGammaAndColorProfile())
m_hasColorProfile = true;
#endif
if (!setSize(WebPDemuxGetI(m_demux, WEBP_FF_CANVAS_WIDTH), WebPDemuxGetI(m_demux, WEBP_FF_CANVAS_HEIGHT)))
return setFailed();
}
ASSERT(ImageDecoder::isSizeAvailable());
const size_t newFrameCount = WebPDemuxGetI(m_demux, WEBP_FF_FRAME_COUNT);
if (hasAnimation && !m_haveReadAnimationParameters && newFrameCount) {
// As we have parsed at least one frame (even if partially),
// we must already have parsed the animation properties.
// This is because ANIM chunk always precedes ANMF chunks.
m_repetitionCount = WebPDemuxGetI(m_demux, WEBP_FF_LOOP_COUNT);
ASSERT(m_repetitionCount == (m_repetitionCount & 0xffff)); // Loop count is always <= 16 bits.
// |m_repetitionCount| is the total number of animation cycles to show,
// with 0 meaning "infinite". But ImageSource::repetitionCount()
// returns -1 for "infinite", and 0 and up for "show the animation one
// cycle more than this value". By subtracting one here, we convert
// both finite and infinite cases correctly.
--m_repetitionCount;
m_haveReadAnimationParameters = true;
}
const size_t oldFrameCount = m_frameBufferCache.size();
if (newFrameCount > oldFrameCount) {
m_frameBufferCache.resize(newFrameCount);
for (size_t i = oldFrameCount; i < newFrameCount; ++i) {
m_frameBufferCache[i].setPremultiplyAlpha(m_premultiplyAlpha);
if (!hasAnimation) {
ASSERT(!i);
m_frameBufferCache[i].setRequiredPreviousFrameIndex(kNotFound);
continue;
}
WebPIterator animatedFrame;
WebPDemuxGetFrame(m_demux, i + 1, &animatedFrame);
ASSERT(animatedFrame.complete == 1);
m_frameBufferCache[i].setDuration(animatedFrame.duration);
m_frameBufferCache[i].setDisposalMethod(animatedFrame.dispose_method == WEBP_MUX_DISPOSE_BACKGROUND ? ImageFrame::DisposeOverwriteBgcolor : ImageFrame::DisposeKeep);
m_frameBufferCache[i].setAlphaBlendSource(animatedFrame.blend_method == WEBP_MUX_BLEND ? ImageFrame::BlendAtopPreviousFrame : ImageFrame::BlendAtopBgcolor);
IntRect frameRect(animatedFrame.x_offset, animatedFrame.y_offset, animatedFrame.width, animatedFrame.height);
// Make sure the frameRect doesn't extend outside the buffer.
if (frameRect.maxX() > size().width())
frameRect.setWidth(size().width() - animatedFrame.x_offset);
if (frameRect.maxY() > size().height())
frameRect.setHeight(size().height() - animatedFrame.y_offset);
m_frameBufferCache[i].setOriginalFrameRect(frameRect);
m_frameBufferCache[i].setRequiredPreviousFrameIndex(findRequiredPreviousFrame(i, !animatedFrame.has_alpha));
WebPDemuxReleaseIterator(&animatedFrame);
}
}
return true;
}
