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// Copyright 2010 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/351564777): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif
#include "third_party/blink/renderer/platform/image-decoders/webp/webp_image_decoder.h"
#include <string.h>
#include <utility>
#include "base/feature_list.h"
#include "base/functional/bind.h"
#include "base/logging.h"
#include "base/metrics/histogram_macros.h"
#include "build/build_config.h"
#include "third_party/blink/renderer/platform/wtf/wtf.h"
#include "third_party/skia/include/core/SkColorSpace.h"
#include "third_party/skia/include/core/SkData.h"
#if defined(ARCH_CPU_BIG_ENDIAN)
#error Blink assumes a little-endian target.
#endif
namespace {
// Returns two point ranges (<left, width> pairs) at row |canvasY| which belong
// to |src| but not |dst|. A range is empty if its width is 0.
inline void findBlendRangeAtRow(const gfx::Rect& src,
const gfx::Rect& dst,
int canvasY,
int& left1,
int& width1,
int& left2,
int& width2) {
SECURITY_DCHECK(canvasY >= src.y() && canvasY < src.bottom());
left1 = -1;
width1 = 0;
left2 = -1;
width2 = 0;
if (canvasY < dst.y() || canvasY >= dst.bottom() || src.x() >= dst.right() ||
src.right() <= dst.x()) {
left1 = src.x();
width1 = src.width();
return;
}
if (src.x() < dst.x()) {
left1 = src.x();
width1 = dst.x() - src.x();
}
if (src.right() > dst.right()) {
left2 = dst.right();
width2 = src.right() - dst.right();
}
}
// alphaBlendPremultiplied and alphaBlendNonPremultiplied are separate methods,
// even though they only differ by one line. This is done so that the compiler
// can inline BlendSrcOverDstPremultiplied() and BlensSrcOverDstRaw() calls.
// For GIF images, this optimization reduces decoding time by 15% for 3MB
// images.
void alphaBlendPremultiplied(blink::ImageFrame& src,
blink::ImageFrame& dst,
int canvasY,
int left,
int width) {
for (int x = 0; x < width; ++x) {
int canvasX = left + x;
blink::ImageFrame::PixelData* pixel = src.GetAddr(canvasX, canvasY);
if (SkPMColorGetA(*pixel) != 0xff) {
blink::ImageFrame::PixelData prevPixel = *dst.GetAddr(canvasX, canvasY);
blink::ImageFrame::BlendSrcOverDstPremultiplied(pixel, prevPixel);
}
}
}
void alphaBlendNonPremultiplied(blink::ImageFrame& src,
blink::ImageFrame& dst,
int canvasY,
int left,
int width) {
for (int x = 0; x < width; ++x) {
int canvasX = left + x;
blink::ImageFrame::PixelData* pixel = src.GetAddr(canvasX, canvasY);
if (SkPMColorGetA(*pixel) != 0xff) {
blink::ImageFrame::PixelData prevPixel = *dst.GetAddr(canvasX, canvasY);
blink::ImageFrame::BlendSrcOverDstRaw(pixel, prevPixel);
}
}
}
// Do not rename entries nor reuse numeric values. See the following link for
// descriptions: https://developers.google.com/speed/webp/docs/riff_container.
enum class WebPFileFormat {
kSimpleLossy = 0,
kSimpleLossless = 1,
kExtendedAlpha = 2,
kExtendedAnimation = 3,
kExtendedAnimationWithAlpha = 4,
kUnknown = 5,
kMaxValue = kUnknown,
};
// Validates that |blob| is a simple lossy WebP image. Note that this explicitly
// checks "WEBPVP8 " to exclude extended lossy WebPs that don't actually use any
// extended features.
//
// TODO(crbug.com/1009237): consider combining this with the logic to detect
// WebPs that can be decoded to YUV.
bool IsSimpleLossyWebPImage(const sk_sp<SkData>& blob) {
if (blob->size() < 20UL) {
return false;
}
DCHECK(blob->bytes());
return !memcmp(blob->bytes(), "RIFF", 4) &&
!memcmp(blob->bytes() + 8UL, "WEBPVP8 ", 8);
}
// This method parses |blob|'s header and emits a UMA with the file format, as
// defined by WebP, see WebPFileFormat.
void UpdateWebPFileFormatUMA(const sk_sp<SkData>& blob) {
if (!IsMainThread()) {
return;
}
WebPBitstreamFeatures features;
if (WebPGetFeatures(blob->bytes(), blob->size(), &features) !=
VP8_STATUS_OK) {
return;
}
// These constants are defined verbatim in
// webp_dec.c::ParseHeadersInternal().
constexpr int kLossyFormat = 1;
constexpr int kLosslessFormat = 2;
WebPFileFormat file_format = WebPFileFormat::kUnknown;
if (features.has_alpha && features.has_animation) {
file_format = WebPFileFormat::kExtendedAnimationWithAlpha;
} else if (features.has_animation) {
file_format = WebPFileFormat::kExtendedAnimation;
} else if (features.has_alpha) {
file_format = WebPFileFormat::kExtendedAlpha;
} else if (features.format == kLossyFormat) {
file_format = WebPFileFormat::kSimpleLossy;
} else if (features.format == kLosslessFormat) {
file_format = WebPFileFormat::kSimpleLossless;
}
UMA_HISTOGRAM_ENUMERATION("Blink.DecodedImage.WebPFileFormat", file_format);
}
} // namespace
namespace blink {
WEBPImageDecoder::WEBPImageDecoder(AlphaOption alpha_option,
ColorBehavior color_behavior,
wtf_size_t max_decoded_bytes)
: ImageDecoder(alpha_option,
ImageDecoder::kDefaultBitDepth,
color_behavior,
cc::AuxImage::kDefault,
max_decoded_bytes) {
blend_function_ = (alpha_option == kAlphaPremultiplied)
? alphaBlendPremultiplied
: alphaBlendNonPremultiplied;
}
WEBPImageDecoder::~WEBPImageDecoder() {
Clear();
}
String WEBPImageDecoder::FilenameExtension() const {
return "webp";
}
const AtomicString& WEBPImageDecoder::MimeType() const {
DEFINE_STATIC_LOCAL(const AtomicString, webp_mime_type, ("image/webp"));
return webp_mime_type;
}
void WEBPImageDecoder::Clear() {
WebPDemuxDelete(demux_);
demux_ = nullptr;
consolidated_data_.reset();
ClearDecoder();
}
void WEBPImageDecoder::ClearDecoder() {
WebPIDelete(decoder_);
decoder_ = nullptr;
decoded_height_ = 0;
frame_background_has_alpha_ = false;
}
WEBP_CSP_MODE WEBPImageDecoder::RGBOutputMode() {
DCHECK(!IsDoingYuvDecode());
if (ColorTransform()) {
// 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.
return MODE_BGRA;
}
bool premultiply = (format_flags_ & ALPHA_FLAG) && premultiply_alpha_;
#if SK_B32_SHIFT // Output little-endian RGBA pixels (Android)
return premultiply ? MODE_rgbA : MODE_RGBA;
#else // Output little-endian BGRA pixels.
return premultiply ? MODE_bgrA : MODE_BGRA;
#endif
}
bool WEBPImageDecoder::CanAllowYUVDecodingForWebP() const {
// Should have been updated with a recent call to UpdateDemuxer().
if (demux_state_ >= WEBP_DEMUX_PARSED_HEADER &&
WebPDemuxGetI(demux_, WEBP_FF_FRAME_COUNT)) {
// TODO(crbug/910276): Change after alpha support.
if (!is_lossy_not_animated_no_alpha_) {
return false;
}
// TODO(crbug/911246): Stop vetoing images with ICCP after Skia supports
// transforming colorspace within YUV, which would allow colorspace
// conversion during decode. Alternatively, look into passing along
// transform for raster-time.
bool has_iccp = !!(format_flags_ & ICCP_FLAG);
return !has_iccp;
}
return false;
}
void WEBPImageDecoder::OnSetData(scoped_refptr<SegmentReader> data) {
have_parsed_current_data_ = false;
// TODO(crbug.com/943519): Modify this approach for incremental YUV (when
// we don't require IsAllDataReceived() to be true before decoding).
if (IsAllDataReceived()) {
UpdateDemuxer();
allow_decode_to_yuv_ = CanAllowYUVDecodingForWebP();
}
}
int WEBPImageDecoder::RepetitionCount() const {
return Failed() ? kAnimationLoopOnce : repetition_count_;
}
bool WEBPImageDecoder::FrameIsReceivedAtIndex(wtf_size_t index) const {
if (!demux_ || demux_state_ < WEBP_DEMUX_PARSED_HEADER) {
return false;
}
if (!(format_flags_ & ANIMATION_FLAG)) {
return ImageDecoder::FrameIsReceivedAtIndex(index);
}
// frame_buffer_cache_.size() is equal to the return value of
// DecodeFrameCount(). WebPDemuxGetI(demux_, WEBP_FF_FRAME_COUNT) returns the
// number of ANMF chunks that have been received. (See also the DCHECK on
// animated_frame.complete in InitializeNewFrame().) Therefore we can return
// true if |index| is valid for frame_buffer_cache_.
bool frame_is_received_at_index = index < frame_buffer_cache_.size();
return frame_is_received_at_index;
}
base::TimeDelta WEBPImageDecoder::FrameDurationAtIndex(wtf_size_t index) const {
return index < frame_buffer_cache_.size()
? frame_buffer_cache_[index].Duration()
: base::TimeDelta();
}
bool WEBPImageDecoder::UpdateDemuxer() {
if (Failed()) {
return false;
}
// RIFF header (12 bytes) + data chunk header (8 bytes).
const unsigned kWebpHeaderSize = 20;
// The number of bytes needed to retrieve the size will vary based on the
// type of chunk (VP8/VP8L/VP8X). This check just serves as an early out
// before bitstream validation can occur.
if (data_->size() < kWebpHeaderSize) {
return IsAllDataReceived() ? SetFailed() : false;
}
if (have_parsed_current_data_) {
return true;
}
have_parsed_current_data_ = true;
if (consolidated_data_ && consolidated_data_->size() >= data_->size()) {
// Less data provided than last time. |consolidated_data_| is guaranteed
// to be its own copy of the data, so it is safe to keep it.
return true;
}
if (IsAllDataReceived() && !consolidated_data_) {
consolidated_data_ = data_->GetAsSkData();
} else {
buffer_.reserve(base::checked_cast<wtf_size_t>(data_->size()));
while (buffer_.size() < data_->size()) {
buffer_.AppendSpan(data_->GetSomeData(buffer_.size()));
}
DCHECK_EQ(buffer_.size(), data_->size());
consolidated_data_ =
SkData::MakeWithoutCopy(buffer_.data(), buffer_.size());
}
WebPDemuxDelete(demux_);
WebPData input_data = {
reinterpret_cast<const uint8_t*>(consolidated_data_->data()),
consolidated_data_->size()};
demux_ = WebPDemuxPartial(&input_data, &demux_state_);
const bool truncated_file =
IsAllDataReceived() && demux_state_ != WEBP_DEMUX_DONE;
if (!demux_ || demux_state_ < WEBP_DEMUX_PARSED_HEADER || truncated_file) {
if (!demux_) {
consolidated_data_.reset();
} else {
// We delete the demuxer early to avoid breaking the expectation that
// frame count == 0 when IsSizeAvailable() is false.
WebPDemuxDelete(demux_);
demux_ = nullptr;
}
return truncated_file ? SetFailed() : false;
}
DCHECK_GE(demux_state_, WEBP_DEMUX_PARSED_HEADER);
if (!WebPDemuxGetI(demux_, WEBP_FF_FRAME_COUNT)) {
return false; // Wait until the encoded image frame data arrives.
}
if (!IsDecodedSizeAvailable()) {
uint32_t width = WebPDemuxGetI(demux_, WEBP_FF_CANVAS_WIDTH);
uint32_t height = WebPDemuxGetI(demux_, WEBP_FF_CANVAS_HEIGHT);
if (!SetSize(base::strict_cast<unsigned>(width),
base::strict_cast<unsigned>(height))) {
return SetFailed();
}
UpdateWebPFileFormatUMA(consolidated_data_);
format_flags_ = WebPDemuxGetI(demux_, WEBP_FF_FORMAT_FLAGS);
if (!(format_flags_ & ANIMATION_FLAG)) {
repetition_count_ = kAnimationNone;
} 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.
repetition_count_ = WebPDemuxGetI(demux_, WEBP_FF_LOOP_COUNT);
// Repetition count is always <= 16 bits.
DCHECK_EQ(repetition_count_, repetition_count_ & 0xffff);
// Repetition count is treated as n + 1 cycles for GIF. WebP defines loop
// count as the number of cycles, with 0 meaning infinite.
repetition_count_ = repetition_count_ == 0 ? kAnimationLoopInfinite
: repetition_count_ - 1;
// FIXME: Implement ICC profile support for animated images.
format_flags_ &= ~ICCP_FLAG;
}
if ((format_flags_ & ICCP_FLAG) && !IgnoresColorSpace()) {
ReadColorProfile();
}
// Record bpp information only for lossy still images that do not have
// alpha.
if (!(format_flags_ & (ANIMATION_FLAG | ALPHA_FLAG))) {
WebPBitstreamFeatures features;
CHECK_EQ(WebPGetFeatures(consolidated_data_->bytes(),
consolidated_data_->size(), &features),
VP8_STATUS_OK);
if (features.format == CompressionFormat::kLossyFormat) {
is_lossy_not_animated_no_alpha_ = true;
static constexpr char kType[] = "WebP";
update_bpp_histogram_callback_ =
base::BindOnce(&UpdateBppHistogram<kType>);
}
}
}
DCHECK(IsDecodedSizeAvailable());
wtf_size_t frame_count = WebPDemuxGetI(demux_, WEBP_FF_FRAME_COUNT);
UpdateAggressivePurging(frame_count);
return true;
}
void WEBPImageDecoder::OnInitFrameBuffer(wtf_size_t frame_index) {
// ImageDecoder::InitFrameBuffer does a DCHECK if |frame_index| exists.
ImageFrame& buffer = frame_buffer_cache_[frame_index];
const wtf_size_t required_previous_frame_index =
buffer.RequiredPreviousFrameIndex();
if (required_previous_frame_index == kNotFound) {
frame_background_has_alpha_ =
!buffer.OriginalFrameRect().Contains(gfx::Rect(Size()));
} else {
const ImageFrame& prev_buffer =
frame_buffer_cache_[required_previous_frame_index];
frame_background_has_alpha_ =
prev_buffer.HasAlpha() || (prev_buffer.GetDisposalMethod() ==
ImageFrame::kDisposeOverwriteBgcolor);
}
// The buffer is transparent outside the decoded area while the image is
// loading. The correct alpha value for the frame will be set when it is fully
// decoded.
buffer.SetHasAlpha(true);
}
void WEBPImageDecoder::DecodeToYUV() {
DCHECK(IsDoingYuvDecode());
// Only 8-bit YUV decode is currently supported.
DCHECK_EQ(image_planes_->color_type(), kGray_8_SkColorType);
if (Failed()) {
return;
}
DCHECK(demux_);
DCHECK(!(format_flags_ & ANIMATION_FLAG));
WebPIterator webp_iter;
// libwebp is 1-indexed.
if (!WebPDemuxGetFrame(demux_, 1 /* frame */, &webp_iter)) {
SetFailed();
} else {
std::unique_ptr<WebPIterator, void (*)(WebPIterator*)> webp_frame(
&webp_iter, WebPDemuxReleaseIterator);
DecodeSingleFrameToYUV(
webp_frame->fragment.bytes,
base::checked_cast<wtf_size_t>(webp_frame->fragment.size));
}
}
gfx::Size WEBPImageDecoder::DecodedYUVSize(cc::YUVIndex index) const {
DCHECK(IsDecodedSizeAvailable());
switch (index) {
case cc::YUVIndex::kY:
return Size();
case cc::YUVIndex::kU:
case cc::YUVIndex::kV:
return gfx::Size((Size().width() + 1) / 2, (Size().height() + 1) / 2);
}
NOTREACHED();
}
wtf_size_t WEBPImageDecoder::DecodedYUVWidthBytes(cc::YUVIndex index) const {
switch (index) {
case cc::YUVIndex::kY:
return base::checked_cast<wtf_size_t>(Size().width());
case cc::YUVIndex::kU:
case cc::YUVIndex::kV:
return base::checked_cast<wtf_size_t>((Size().width() + 1) / 2);
}
NOTREACHED();
}
SkYUVColorSpace WEBPImageDecoder::GetYUVColorSpace() const {
return SkYUVColorSpace::kRec601_SkYUVColorSpace;
}
cc::YUVSubsampling WEBPImageDecoder::GetYUVSubsampling() const {
DCHECK(consolidated_data_);
if (IsSimpleLossyWebPImage(consolidated_data_)) {
return cc::YUVSubsampling::k420;
}
// It is possible for a non-simple lossy WebP to also be YUV 4:2:0. However,
// we're being conservative here because this is currently only used for
// hardware decode acceleration, and WebPs other than simple lossy are not
// supported in that path anyway.
return cc::YUVSubsampling::kUnknown;
}
bool WEBPImageDecoder::CanReusePreviousFrameBuffer(
wtf_size_t frame_index) const {
DCHECK(frame_index < frame_buffer_cache_.size());
return frame_buffer_cache_[frame_index].GetAlphaBlendSource() !=
ImageFrame::kBlendAtopPreviousFrame;
}
void WEBPImageDecoder::ClearFrameBuffer(wtf_size_t frame_index) {
if (demux_ && demux_state_ >= WEBP_DEMUX_PARSED_HEADER &&
frame_buffer_cache_[frame_index].GetStatus() ==
ImageFrame::kFramePartial) {
// Clear the decoder state so that this partial frame can be decoded again
// when requested.
ClearDecoder();
}
ImageDecoder::ClearFrameBuffer(frame_index);
}
void WEBPImageDecoder::ReadColorProfile() {
WebPChunkIterator chunk_iterator;
if (!WebPDemuxGetChunk(demux_, "ICCP", 1, &chunk_iterator)) {
WebPDemuxReleaseChunkIterator(&chunk_iterator);
return;
}
wtf_size_t profile_size =
base::checked_cast<wtf_size_t>(chunk_iterator.chunk.size);
if (auto profile = ColorProfile::Create(
base::span(chunk_iterator.chunk.bytes, profile_size))) {
if (profile->GetProfile()->data_color_space == skcms_Signature_RGB) {
SetEmbeddedColorProfile(std::move(profile));
}
} else {
DLOG(ERROR) << "Failed to parse image ICC profile";
}
WebPDemuxReleaseChunkIterator(&chunk_iterator);
}
void WEBPImageDecoder::ApplyPostProcessing(wtf_size_t frame_index) {
ImageFrame& buffer = frame_buffer_cache_[frame_index];
int width;
int decoded_height;
// TODO(crbug.com/911246): Do post-processing once skcms_Transform
// supports multiplanar formats.
DCHECK(!IsDoingYuvDecode());
if (!WebPIDecGetRGB(decoder_, &decoded_height, &width, nullptr, nullptr)) {
return; // See also https://bugs.webkit.org/show_bug.cgi?id=74062
}
if (decoded_height <= 0) {
return;
}
const gfx::Rect& frame_rect = buffer.OriginalFrameRect();
SECURITY_DCHECK(width == frame_rect.width());
SECURITY_DCHECK(decoded_height <= frame_rect.height());
const int left = frame_rect.x();
const int top = frame_rect.y();
// TODO (msarett):
// Here we apply the color space transformation to the dst space.
// It does not really make sense to transform to a gamma-encoded
// space and then immediately after, perform a linear premultiply
// and linear blending. Can we find a way to perform the
// premultiplication and blending in a linear space?
ColorProfileTransform* xform = ColorTransform();
if (xform) {
skcms_PixelFormat kSrcFormat = skcms_PixelFormat_BGRA_8888;
skcms_PixelFormat kDstFormat = skcms_PixelFormat_RGBA_8888;
skcms_AlphaFormat alpha_format = skcms_AlphaFormat_Unpremul;
for (int y = decoded_height_; y < decoded_height; ++y) {
const int canvas_y = top + y;
uint8_t* row = reinterpret_cast<uint8_t*>(buffer.GetAddr(left, canvas_y));
bool color_conversion_successful = skcms_Transform(
row, kSrcFormat, alpha_format, xform->SrcProfile(), row, kDstFormat,
alpha_format, xform->DstProfile(), width);
DCHECK(color_conversion_successful);
uint8_t* pixel = row;
for (int x = 0; x < width; ++x, pixel += 4) {
const int canvas_x = left + x;
buffer.SetRGBA(canvas_x, canvas_y, pixel[0], pixel[1], pixel[2],
pixel[3]);
}
}
}
// During the decoding of the current frame, we may have set some pixels to be
// transparent (i.e. alpha < 255). If the alpha blend source was
// 'BlendAtopPreviousFrame', the values of these pixels should be
// determined by blending them against the pixels of the corresponding
// previous frame. Compute the correct opaque values now.
// 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 ((format_flags_ & ANIMATION_FLAG) && frame_index &&
buffer.GetAlphaBlendSource() == ImageFrame::kBlendAtopPreviousFrame &&
buffer.RequiredPreviousFrameIndex() != kNotFound) {
ImageFrame& prev_buffer = frame_buffer_cache_[frame_index - 1];
DCHECK_EQ(prev_buffer.GetStatus(), ImageFrame::kFrameComplete);
ImageFrame::DisposalMethod prev_disposal_method =
prev_buffer.GetDisposalMethod();
if (prev_disposal_method == ImageFrame::kDisposeKeep) {
// Blend transparent pixels with pixels in previous canvas.
for (int y = decoded_height_; y < decoded_height; ++y) {
blend_function_(buffer, prev_buffer, top + y, left, width);
}
} else if (prev_disposal_method == ImageFrame::kDisposeOverwriteBgcolor) {
const gfx::Rect& prev_rect = prev_buffer.OriginalFrameRect();
// We need to blend a transparent pixel with the starting value (from just
// after the InitFrame() call). If the pixel belongs to prev_rect, the
// starting value was fully transparent, so this is a no-op. Otherwise, we
// need to blend against the pixel from the previous canvas.
for (int y = decoded_height_; y < decoded_height; ++y) {
int canvas_y = top + y;
int left1, width1, left2, width2;
findBlendRangeAtRow(frame_rect, prev_rect, canvas_y, left1, width1,
left2, width2);
if (width1 > 0) {
blend_function_(buffer, prev_buffer, canvas_y, left1, width1);
}
if (width2 > 0) {
blend_function_(buffer, prev_buffer, canvas_y, left2, width2);
}
}
}
}
decoded_height_ = decoded_height;
buffer.SetPixelsChanged(true);
}
void WEBPImageDecoder::DecodeSize() {
UpdateDemuxer();
}
wtf_size_t WEBPImageDecoder::DecodeFrameCount() {
// If UpdateDemuxer() fails, return the existing number of frames. This way if
// we get halfway through the image before decoding fails, we won't suddenly
// start reporting that the image has zero frames.
return UpdateDemuxer() ? WebPDemuxGetI(demux_, WEBP_FF_FRAME_COUNT)
: frame_buffer_cache_.size();
}
void WEBPImageDecoder::InitializeNewFrame(wtf_size_t index) {
if (!(format_flags_ & ANIMATION_FLAG)) {
DCHECK(!index);
return;
}
WebPIterator animated_frame;
if (!WebPDemuxGetFrame(demux_, index + 1, &animated_frame)) {
SetFailed();
return;
}
DCHECK_EQ(animated_frame.complete, 1);
ImageFrame* buffer = &frame_buffer_cache_[index];
gfx::Rect frame_rect(animated_frame.x_offset, animated_frame.y_offset,
animated_frame.width, animated_frame.height);
buffer->SetOriginalFrameRect(IntersectRects(frame_rect, gfx::Rect(Size())));
buffer->SetDuration(base::Milliseconds(animated_frame.duration));
buffer->SetDisposalMethod(animated_frame.dispose_method ==
WEBP_MUX_DISPOSE_BACKGROUND
? ImageFrame::kDisposeOverwriteBgcolor
: ImageFrame::kDisposeKeep);
buffer->SetAlphaBlendSource(animated_frame.blend_method == WEBP_MUX_BLEND
? ImageFrame::kBlendAtopPreviousFrame
: ImageFrame::kBlendAtopBgcolor);
buffer->SetRequiredPreviousFrameIndex(
FindRequiredPreviousFrame(index, !animated_frame.has_alpha));
WebPDemuxReleaseIterator(&animated_frame);
}
void WEBPImageDecoder::Decode(wtf_size_t index) {
DCHECK(!IsDoingYuvDecode());
if (Failed()) {
return;
}
Vector<wtf_size_t> frames_to_decode = FindFramesToDecode(index);
DCHECK(demux_);
for (auto i = frames_to_decode.rbegin(); i != frames_to_decode.rend(); ++i) {
if ((format_flags_ & ANIMATION_FLAG) && !InitFrameBuffer(*i)) {
SetFailed();
return;
}
WebPIterator webp_iter;
if (!WebPDemuxGetFrame(demux_, *i + 1, &webp_iter)) {
SetFailed();
} else {
std::unique_ptr<WebPIterator, void (*)(WebPIterator*)> webp_frame(
&webp_iter, WebPDemuxReleaseIterator);
DecodeSingleFrame(
webp_frame->fragment.bytes,
base::checked_cast<wtf_size_t>(webp_frame->fragment.size), *i);
}
if (Failed()) {
return;
}
// If this returns false, we need more data to continue decoding.
if (!PostDecodeProcessing(*i)) {
break;
}
}
// It is also a fatal error if all data is received and we have decoded all
// frames available but the file is truncated.
if (index >= frame_buffer_cache_.size() - 1 && IsAllDataReceived() &&
demux_ && demux_state_ != WEBP_DEMUX_DONE) {
SetFailed();
}
}
bool WEBPImageDecoder::DecodeSingleFrameToYUV(const uint8_t* data_bytes,
wtf_size_t data_size) {
DCHECK(IsDoingYuvDecode());
DCHECK(!Failed());
bool size_available_after_init = IsSizeAvailable();
DCHECK(size_available_after_init);
// Set up decoder_buffer_ with output mode
if (!decoder_) {
if (!WebPInitDecBuffer(&decoder_buffer_)) {
return SetFailed();
}
decoder_buffer_.colorspace = MODE_YUV; // TODO(crbug.com/910276): Change
// after alpha YUV support is added.
}
ImagePlanes* image_planes = image_planes_.get();
DCHECK(image_planes);
// Even if |decoder_| already exists, we must get most up-to-date pointers
// because memory location might change e.g. upon tab resume.
decoder_buffer_.u.YUVA.y =
static_cast<uint8_t*>(image_planes->Plane(cc::YUVIndex::kY));
decoder_buffer_.u.YUVA.u =
static_cast<uint8_t*>(image_planes->Plane(cc::YUVIndex::kU));
decoder_buffer_.u.YUVA.v =
static_cast<uint8_t*>(image_planes->Plane(cc::YUVIndex::kV));
if (!decoder_) {
// libwebp only supports YUV 420 subsampling
decoder_buffer_.u.YUVA.y_stride = image_planes->RowBytes(cc::YUVIndex::kY);
decoder_buffer_.u.YUVA.y_size = decoder_buffer_.u.YUVA.y_stride *
DecodedYUVSize(cc::YUVIndex::kY).height();
decoder_buffer_.u.YUVA.u_stride = image_planes->RowBytes(cc::YUVIndex::kU);
decoder_buffer_.u.YUVA.u_size = decoder_buffer_.u.YUVA.u_stride *
DecodedYUVSize(cc::YUVIndex::kU).height();
decoder_buffer_.u.YUVA.v_stride = image_planes->RowBytes(cc::YUVIndex::kV);
decoder_buffer_.u.YUVA.v_size = decoder_buffer_.u.YUVA.v_stride *
DecodedYUVSize(cc::YUVIndex::kV).height();
decoder_buffer_.is_external_memory = 1;
decoder_ = WebPINewDecoder(&decoder_buffer_);
if (!decoder_) {
return SetFailed();
}
}
if (WebPIUpdate(decoder_, data_bytes, data_size) != VP8_STATUS_OK) {
Clear();
return SetFailed();
}
// TODO(crbug.com/911246): Do post-processing once skcms_Transform
// supports multiplanar formats.
ClearDecoder();
image_planes->SetHasCompleteScan();
if (IsAllDataReceived() && update_bpp_histogram_callback_) {
std::move(update_bpp_histogram_callback_).Run(Size(), data_->size());
}
return true;
}
bool WEBPImageDecoder::DecodeSingleFrame(const uint8_t* data_bytes,
wtf_size_t data_size,
wtf_size_t frame_index) {
DCHECK(!IsDoingYuvDecode());
if (Failed()) {
return false;
}
DCHECK(IsDecodedSizeAvailable());
DCHECK_GT(frame_buffer_cache_.size(), frame_index);
ImageFrame& buffer = frame_buffer_cache_[frame_index];
DCHECK_NE(buffer.GetStatus(), ImageFrame::kFrameComplete);
if (buffer.GetStatus() == ImageFrame::kFrameEmpty) {
if (!buffer.AllocatePixelData(Size().width(), Size().height(),
ColorSpaceForSkImages())) {
return SetFailed();
}
buffer.ZeroFillPixelData();
buffer.SetStatus(ImageFrame::kFramePartial);
// The buffer is transparent outside the decoded area while the image
// is loading. The correct alpha value for the frame will be set when
// it is fully decoded.
buffer.SetHasAlpha(true);
buffer.SetOriginalFrameRect(gfx::Rect(Size()));
}
const gfx::Rect& frame_rect = buffer.OriginalFrameRect();
if (!decoder_) {
// Set up decoder_buffer_ with output mode
if (!WebPInitDecBuffer(&decoder_buffer_)) {
return SetFailed();
}
decoder_buffer_.colorspace = RGBOutputMode();
decoder_buffer_.u.RGBA.stride =
Size().width() * sizeof(ImageFrame::PixelData);
decoder_buffer_.u.RGBA.size =
decoder_buffer_.u.RGBA.stride * frame_rect.height();
decoder_buffer_.is_external_memory = 1;
decoder_ = WebPINewDecoder(&decoder_buffer_);
if (!decoder_) {
return SetFailed();
}
}
decoder_buffer_.u.RGBA.rgba = reinterpret_cast<uint8_t*>(
buffer.GetAddr(frame_rect.x(), frame_rect.y()));
switch (WebPIUpdate(decoder_, data_bytes, data_size)) {
case VP8_STATUS_OK:
ApplyPostProcessing(frame_index);
buffer.SetHasAlpha((format_flags_ & ALPHA_FLAG) ||
frame_background_has_alpha_);
buffer.SetStatus(ImageFrame::kFrameComplete);
ClearDecoder();
if (IsAllDataReceived() && update_bpp_histogram_callback_) {
std::move(update_bpp_histogram_callback_).Run(Size(), data_->size());
}
return true;
case VP8_STATUS_SUSPENDED:
if (!IsAllDataReceived() && !FrameIsReceivedAtIndex(frame_index)) {
ApplyPostProcessing(frame_index);
return false;
}
[[fallthrough]];
default:
Clear();
return SetFailed();
}
}
cc::ImageHeaderMetadata WEBPImageDecoder::MakeMetadataForDecodeAcceleration()
const {
cc::ImageHeaderMetadata image_metadata =
ImageDecoder::MakeMetadataForDecodeAcceleration();
DCHECK(consolidated_data_);
image_metadata.webp_is_non_extended_lossy =
IsSimpleLossyWebPImage(consolidated_data_);
return image_metadata;
}
bool WEBPImageDecoder::FrameStatusSufficientForSuccessors(wtf_size_t index) {
DCHECK(index < frame_buffer_cache_.size());
return frame_buffer_cache_[index].GetStatus() == ImageFrame::kFrameComplete;
}
} // namespace blink
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