/* * 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 "SkBitmap.h" #include "SkCanvas.h" #include "SkCodecAnimation.h" #include "SkCodecAnimationPriv.h" #include "SkCodecPriv.h" #include "SkColorSpaceXform.h" #include "SkMakeUnique.h" #include "SkRasterPipeline.h" #include "SkSampler.h" #include "SkStreamPriv.h" #include "SkTemplates.h" #include "SkWebpCodec.h" #include "../jumper/SkJumper.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(buf); return bytesRead >= 14 && !memcmp(bytes, "RIFF", 4) && !memcmp(&bytes[8], "WEBPVP", 6); } static SkAlphaType alpha_type(bool hasAlpha) { return hasAlpha ? kUnpremul_SkAlphaType : kOpaque_SkAlphaType; } // Parse headers of RIFF container, and check for valid Webp (VP8) content. // Returns an SkWebpCodec on success std::unique_ptr SkWebpCodec::MakeFromStream(std::unique_ptr stream, Result* result) { // Webp demux needs a contiguous data buffer. sk_sp 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 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 (!sk_64_isS32(size) || sk_64_asS32(size) > (0x7FFFFFFF >> 2)) { *result = kInvalidInput; return nullptr; } } WebPChunkIterator chunkIterator; SkAutoTCallVProc autoCI(&chunkIterator); sk_sp colorSpace = nullptr; if (WebPDemuxGetChunk(demux, "ICCP", 1, &chunkIterator)) { colorSpace = SkColorSpace::MakeICC(chunkIterator.chunk.bytes, chunkIterator.chunk.size); } if (!colorSpace) { colorSpace = SkColorSpace::MakeSRGB(); } // Get the first frame and its "features" to determine the color and alpha types. WebPIterator frame; SkAutoTCallVProc 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(color, alpha, 8); return std::unique_ptr(new SkWebpCodec(width, height, info, std::move(colorSpace), std::move(stream), demux.release(), std::move(data))); } SkISize SkWebpCodec::onGetScaledDimensions(float desiredScale) const { SkISize dim = this->getInfo().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 SkImageInfo& info = this->getInfo(); return dim.width() >= 1 && dim.width() <= info.width() && dim.height() >= 1 && dim.height() <= info.height(); } static WEBP_CSP_MODE webp_decode_mode(const SkImageInfo& info) { const bool premultiply = info.alphaType() == kPremul_SkAlphaType; switch (info.colorType()) { 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); return &fFrames[i]; } bool SkWebpCodec::onGetValidSubset(SkIRect* desiredSubset) const { if (!desiredSubset) { return false; } SkIRect dimensions = SkIRect::MakeSize(this->getInfo().dimensions()); if (!dimensions.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 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(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->fAlpha = frame->hasAlpha() ? SkEncodedInfo::kUnpremul_Alpha : SkEncodedInfo::kOpaque_Alpha; 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; } } static void pick_memory_stages(SkColorType ct, SkRasterPipeline::StockStage* load, SkRasterPipeline::StockStage* store) { switch(ct) { case kUnknown_SkColorType: case kAlpha_8_SkColorType: case kARGB_4444_SkColorType: case kGray_8_SkColorType: SkASSERT(false); break; case kRGB_565_SkColorType: if (load) *load = SkRasterPipeline::load_565; if (store) *store = SkRasterPipeline::store_565; break; case kRGBA_8888_SkColorType: if (load) *load = SkRasterPipeline::load_8888; if (store) *store = SkRasterPipeline::store_8888; break; case kBGRA_8888_SkColorType: if (load) *load = SkRasterPipeline::load_bgra; if (store) *store = SkRasterPipeline::store_bgra; break; case kRGBA_F16_SkColorType: if (load) *load = SkRasterPipeline::load_f16; if (store) *store = SkRasterPipeline::store_f16; break; } } static void blend_line(SkColorType dstCT, void* dst, SkColorType srcCT, const void* src, bool needsSrgbToLinear, SkAlphaType at, int width) { // Setup conversion from the source and dest, which will be the same. SkRasterPipeline_<256> convert_to_linear_premul; if (needsSrgbToLinear) { convert_to_linear_premul.append_from_srgb(at); } if (kUnpremul_SkAlphaType == at) { // srcover assumes premultiplied inputs. convert_to_linear_premul.append(SkRasterPipeline::premul); } SkJumper_MemoryCtx dst_ctx = { (void*)dst, 0 }, src_ctx = { (void*)src, 0 }; SkRasterPipeline_<256> p; SkRasterPipeline::StockStage load_dst, store_dst; pick_memory_stages(dstCT, &load_dst, &store_dst); // Load the final dst. p.append(load_dst, &dst_ctx); p.extend(convert_to_linear_premul); p.append(SkRasterPipeline::move_src_dst); // Load the src. SkRasterPipeline::StockStage load_src; pick_memory_stages(srcCT, &load_src, nullptr); p.append(load_src, &src_ctx); p.extend(convert_to_linear_premul); p.append(SkRasterPipeline::srcover); // Convert back to dst. if (kUnpremul_SkAlphaType == at) { p.append(SkRasterPipeline::unpremul); } if (needsSrgbToLinear) { p.append(SkRasterPipeline::to_srgb); } p.append(store_dst, &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()); const auto& srcInfo = this->getInfo(); SkASSERT(0 == index || (!options.fSubset && dstInfo.dimensions() == srcInfo.dimensions())); 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 autoFree(&(config.output)); WebPIterator frame; SkAutoTCallVProc 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() == kNone); // 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(srcInfo.bounds().contains(frameRect)); const bool frameIsSubset = frameRect != srcInfo.bounds(); if (independent && frameIsSubset) { SkSampler::Fill(dstInfo, dst, rowBytes, 0, 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->getInfo().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() : srcInfo.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; if (blendWithPrevFrame && options.fPremulBehavior == SkTransferFunctionBehavior::kRespect) { // Blending is done with SkRasterPipeline, which requires a color space that is valid for // rendering. const auto* cs = dstInfo.colorSpace(); if (!cs || (!cs->gammaCloseToSRGB() && !cs->gammaIsLinear())) { return kInvalidConversion; } } 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); config.output.is_external_memory = 1; config.output.u.RGBA.rgba = reinterpret_cast(webpDst.getAddr(dstX, dstY)); config.output.u.RGBA.stride = static_cast(webpDst.rowBytes()); config.output.u.RGBA.size = webpDst.computeByteSize(); SkAutoTCallVProc idec(WebPIDecode(nullptr, 0, &config)); if (!idec) { return kInvalidInput; } int rowsDecoded; 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: WebPIDecGetRGB(idec, &rowsDecoded, nullptr, nullptr, nullptr); *rowsDecodedPtr = rowsDecoded + dstY; result = kIncompleteInput; break; default: return kInvalidInput; } // We're only transforming the new part of the frame, so no need to worry about the // final composited alpha. const auto srcAlpha = 0 == index ? srcInfo.alphaType() : alpha_type(frame.has_alpha); const auto xformAlphaType = select_xform_alpha(dstInfo.alphaType(), srcAlpha); const bool needsSrgbToLinear = dstInfo.gammaCloseToSRGB() && options.fPremulBehavior == SkTransferFunctionBehavior::kRespect; const size_t dstBpp = SkColorTypeBytesPerPixel(dstInfo.colorType()); dst = SkTAddOffset(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, xformAlphaType); if (blendWithPrevFrame) { blend_line(dstCT, dst, dstCT, xformDst, needsSrgbToLinear, xformAlphaType, scaledWidth); dst = SkTAddOffset(dst, rowBytes); } else { xformDst = SkTAddOffset(xformDst, rowBytes); } xformSrc = SkTAddOffset(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, needsSrgbToLinear, xformAlphaType, scaledWidth); src = SkTAddOffset(src, srcRowBytes); dst = SkTAddOffset(dst, rowBytes); } } return result; } SkWebpCodec::SkWebpCodec(int width, int height, const SkEncodedInfo& info, sk_sp colorSpace, std::unique_ptr stream, WebPDemuxer* demux, sk_sp data) : INHERITED(width, height, info, SkColorSpaceXform::kBGRA_8888_ColorFormat, std::move(stream), std::move(colorSpace)) , fDemux(demux) , fData(std::move(data)) , fFailed(false) { fFrameHolder.setScreenSize(width, height); }