/*
* Copyright 2015 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkWebpCodec.h"
#include "SkBitmap.h"
#include "SkCanvas.h"
#include "SkCodecAnimation.h"
#include "SkCodecAnimationPriv.h"
#include "SkCodecPriv.h"
#include "SkMakeUnique.h"
#include "SkRasterPipeline.h"
#include "SkSampler.h"
#include "SkStreamPriv.h"
#include "SkTemplates.h"
#include "SkTo.h"
// A WebP decoder on top of (subset of) libwebp
// For more information on WebP image format, and libwebp library, see:
// https://code.google.com/speed/webp/
// http://www.webmproject.org/code/#libwebp-webp-image-library
// https://chromium.googlesource.com/webm/libwebp
// If moving libwebp out of skia source tree, path for webp headers must be
// updated accordingly. Here, we enforce using local copy in webp sub-directory.
#include "webp/decode.h"
#include "webp/demux.h"
#include "webp/encode.h"
bool SkWebpCodec::IsWebp(const void* buf, size_t bytesRead) {
// 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);
}
// Parse headers of RIFF container, and check for valid Webp (VP8) content.
// Returns an SkWebpCodec on success
std::unique_ptr<SkCodec> SkWebpCodec::MakeFromStream(std::unique_ptr<SkStream> stream,
Result* result) {
// 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);
// Sanity check for 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)) {
is_orientation_marker(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));
}
SkISize SkWebpCodec::onGetScaledDimensions(float desiredScale) const {
SkISize dim = this->dimensions();
// SkCodec treats zero dimensional images as errors, so the minimum size
// that we will recommend is 1x1.
dim.fWidth = SkTMax(1, SkScalarRoundToInt(desiredScale * dim.fWidth));
dim.fHeight = SkTMax(1, SkScalarRoundToInt(desiredScale * dim.fHeight));
return dim;
}
bool SkWebpCodec::onDimensionsSupported(const SkISize& dim) {
const SkEncodedInfo& info = this->getEncodedInfo();
return dim.width() >= 1 && dim.width() <= info.width()
&& dim.height() >= 1 && dim.height() <= info.height();
}
static WEBP_CSP_MODE webp_decode_mode(SkColorType dstCT, bool premultiply) {
switch (dstCT) {
case kBGRA_8888_SkColorType:
return premultiply ? MODE_bgrA : MODE_BGRA;
case kRGBA_8888_SkColorType:
return premultiply ? MODE_rgbA : MODE_RGBA;
case kRGB_565_SkColorType:
return MODE_RGB_565;
default:
return MODE_LAST;
}
}
SkWebpCodec::Frame* SkWebpCodec::FrameHolder::appendNewFrame(bool hasAlpha) {
const int i = this->size();
fFrames.emplace_back(i, hasAlpha ? SkEncodedInfo::kUnpremul_Alpha
: SkEncodedInfo::kOpaque_Alpha);
return &fFrames[i];
}
bool SkWebpCodec::onGetValidSubset(SkIRect* desiredSubset) const {
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;
}
int SkWebpCodec::onGetRepetitionCount() {
auto flags = WebPDemuxGetI(fDemux.get(), WEBP_FF_FORMAT_FLAGS);
if (!(flags & ANIMATION_FLAG)) {
return 0;
}
const int repCount = WebPDemuxGetI(fDemux.get(), WEBP_FF_LOOP_COUNT);
if (0 == repCount) {
return kRepetitionCountInfinite;
}
return repCount;
}
int SkWebpCodec::onGetFrameCount() {
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::kBG);
}
fFrameHolder.setAlphaAndRequiredFrame(frame);
}
return fFrameHolder.size();
}
const SkFrame* SkWebpCodec::FrameHolder::onGetFrame(int i) const {
return static_cast<const SkFrame*>(this->frame(i));
}
const SkWebpCodec::Frame* SkWebpCodec::FrameHolder::frame(int i) const {
SkASSERT(i >= 0 && i < this->size());
return &fFrames[i];
}
bool SkWebpCodec::onGetFrameInfo(int i, FrameInfo* frameInfo) const {
if (i >= fFrameHolder.size()) {
return false;
}
const Frame* frame = fFrameHolder.frame(i);
if (!frame) {
return false;
}
if (frameInfo) {
frameInfo->fRequiredFrame = frame->getRequiredFrame();
frameInfo->fDuration = frame->getDuration();
// libwebp only reports fully received frames for an
// animated image.
frameInfo->fFullyReceived = true;
frameInfo->fAlphaType = frame->hasAlpha() ? kUnpremul_SkAlphaType
: kOpaque_SkAlphaType;
frameInfo->fDisposalMethod = frame->getDisposalMethod();
}
return true;
}
static bool is_8888(SkColorType colorType) {
switch (colorType) {
case kRGBA_8888_SkColorType:
case kBGRA_8888_SkColorType:
return true;
default:
return false;
}
}
// Requires that the src input be unpremultiplied (or opaque).
static void blend_line(SkColorType dstCT, void* dst,
SkColorType srcCT, const void* src,
SkAlphaType dstAt,
bool srcHasAlpha,
int width) {
SkRasterPipeline_MemoryCtx dst_ctx = { (void*)dst, 0 },
src_ctx = { (void*)src, 0 };
SkRasterPipeline_<256> p;
p.append_load_dst(dstCT, &dst_ctx);
if (kUnpremul_SkAlphaType == dstAt) {
p.append(SkRasterPipeline::premul_dst);
}
p.append_load(srcCT, &src_ctx);
if (srcHasAlpha) {
p.append(SkRasterPipeline::premul);
}
p.append(SkRasterPipeline::srcover);
if (kUnpremul_SkAlphaType == dstAt) {
p.append(SkRasterPipeline::unpremul);
}
p.append_store(dstCT, &dst_ctx);
p.run(0,0, width,1);
}
SkCodec::Result SkWebpCodec::onGetPixels(const SkImageInfo& dstInfo, void* dst, size_t rowBytes,
const Options& options, int* rowsDecodedPtr) {
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::IntersectsNoEmptyCheck(subset, frameRect)) {
return kSuccess;
}
int minXOffset = SkTMin(dstX, subset.x());
int minYOffset = SkTMin(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;
SkBitmap webpDst;
auto webpInfo = dstInfo;
if (!frame.has_alpha) {
webpInfo = webpInfo.makeAlphaType(kOpaque_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);
if (webpInfo.alphaType() == kPremul_SkAlphaType) {
webpInfo = webpInfo.makeAlphaType(kUnpremul_SkAlphaType);
}
}
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(),
frame.has_alpha && dstInfo.alphaType() == kPremul_SkAlphaType && !this->colorXform());
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;
}
SkWebpCodec::SkWebpCodec(SkEncodedInfo&& info, std::unique_ptr<SkStream> stream,
WebPDemuxer* demux, sk_sp<SkData> data, SkEncodedOrigin origin)
: INHERITED(std::move(info), skcms_PixelFormat_BGRA_8888, std::move(stream),
origin)
, fDemux(demux)
, fData(std::move(data))
, fFailed(false)
{
const auto& eInfo = this->getEncodedInfo();
fFrameHolder.setScreenSize(eInfo.width(), eInfo.height());
}