| /* |
| * 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 "SkCodecPriv.h" |
| #include "SkColorSpaceXform.h" |
| #include "SkWebpCodec.h" |
| #include "SkStreamPriv.h" |
| #include "SkTemplates.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. |
| // NOTE: This calls peek instead of read, since onGetPixels will need these |
| // bytes again. |
| // Returns an SkWebpCodec on success; |
| SkCodec* SkWebpCodec::NewFromStream(SkStream* stream) { |
| SkAutoTDelete<SkStream> streamDeleter(stream); |
| |
| // 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); |
| |
| // If we are forced to copy the stream to a data, we can go ahead and delete the stream. |
| streamDeleter.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() }; |
| SkAutoTCallVProc<WebPDemuxer, WebPDemuxDelete> demux(WebPDemuxPartial(&webpData, nullptr)); |
| if (nullptr == demux) { |
| return nullptr; |
| } |
| |
| WebPChunkIterator chunkIterator; |
| SkAutoTCallVProc<WebPChunkIterator, WebPDemuxReleaseChunkIterator> autoCI(&chunkIterator); |
| sk_sp<SkColorSpace> colorSpace = nullptr; |
| if (WebPDemuxGetChunk(demux, "ICCP", 1, &chunkIterator)) { |
| colorSpace = SkColorSpace::NewICC(chunkIterator.chunk.bytes, chunkIterator.chunk.size); |
| } |
| |
| if (!colorSpace) { |
| colorSpace = SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named); |
| } |
| |
| // Since we do not yet support animation, we get the |width|, |height|, |color|, and |alpha| |
| // from the first frame. It's the only frame we will decode. |
| // |
| // TODO: |
| // When we support animation, we'll want to report the canvas width and canvas height instead. |
| // We can get these from the |demux| directly. |
| // What |color| and |alpha| will we want to report though? WebP allows different frames |
| // to be encoded in different ways, making the encoded format difficult to describe. |
| WebPIterator frame; |
| SkAutoTCallVProc<WebPIterator, WebPDemuxReleaseIterator> autoFrame(&frame); |
| if (!WebPDemuxGetFrame(demux, 1, &frame)) { |
| return nullptr; |
| } |
| |
| // Sanity check for image size that's about to be decoded. |
| { |
| const int64_t size = sk_64_mul(frame.width, frame.height); |
| if (!sk_64_isS32(size)) { |
| return nullptr; |
| } |
| // now check that if we are 4-bytes per pixel, we also don't overflow |
| if (sk_64_asS32(size) > (0x7FFFFFFF >> 2)) { |
| return nullptr; |
| } |
| } |
| |
| // TODO: |
| // The only reason we actually need to call WebPGetFeatures() is to get the |features.format|. |
| // This call actually re-reads the frame header. Should we suggest that libwebp expose |
| // the format on the |frame|? |
| WebPBitstreamFeatures features; |
| VP8StatusCode status = WebPGetFeatures(frame.fragment.bytes, frame.fragment.size, &features); |
| if (VP8_STATUS_OK != status) { |
| return nullptr; |
| } |
| |
| SkEncodedInfo::Color color; |
| SkEncodedInfo::Alpha alpha; |
| switch (features.format) { |
| case 0: |
| // This indicates a "mixed" format. We would see this for |
| // animated webps or for webps encoded in multiple fragments. |
| // I believe that this is a rare case. |
| // 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. |
| color = SkEncodedInfo::kBGRA_Color; |
| alpha = SkEncodedInfo::kUnpremul_Alpha; |
| break; |
| case 1: |
| // This is the lossy format (YUV). |
| if (SkToBool(features.has_alpha)) { |
| color = SkEncodedInfo::kYUVA_Color; |
| alpha = SkEncodedInfo::kUnpremul_Alpha; |
| } else { |
| color = SkEncodedInfo::kYUV_Color; |
| alpha = SkEncodedInfo::kOpaque_Alpha; |
| } |
| break; |
| case 2: |
| // This is the lossless format (BGRA). |
| color = SkEncodedInfo::kBGRA_Color; |
| alpha = SkEncodedInfo::kUnpremul_Alpha; |
| break; |
| default: |
| return nullptr; |
| } |
| |
| SkEncodedInfo info = SkEncodedInfo::Make(color, alpha, 8); |
| return new SkWebpCodec(features.width, features.height, info, std::move(colorSpace), |
| streamDeleter.release(), 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(SkColorType ct, bool premultiply) { |
| switch (ct) { |
| 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; |
| } |
| } |
| |
| 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; |
| } |
| |
| SkCodec::Result SkWebpCodec::onGetPixels(const SkImageInfo& dstInfo, void* dst, size_t rowBytes, |
| const Options& options, SkPMColor*, int*, |
| int* rowsDecodedPtr) { |
| if (!conversion_possible(dstInfo, this->getInfo())) { |
| return kInvalidConversion; |
| } |
| |
| std::unique_ptr<SkColorSpaceXform> colorXform = nullptr; |
| if (needs_color_xform(dstInfo, this->getInfo())) { |
| colorXform = SkColorSpaceXform::New(this->getInfo().colorSpace(), dstInfo.colorSpace()); |
| SkASSERT(colorXform); |
| } |
| |
| 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)); |
| |
| SkIRect bounds = SkIRect::MakeSize(this->getInfo().dimensions()); |
| if (options.fSubset) { |
| // Caller is requesting a subset. |
| if (!bounds.contains(*options.fSubset)) { |
| // The subset is out of bounds. |
| return kInvalidParameters; |
| } |
| |
| bounds = *options.fSubset; |
| |
| // This is tricky. libwebp snaps the top and left to even values. We could let libwebp |
| // do the snap, and return a subset which is a different one than requested. The problem |
| // with that approach is that the caller may try to stitch subsets together, and if we |
| // returned different subsets than requested, there would be artifacts at the boundaries. |
| // Instead, we report that we cannot support odd values for top and left.. |
| if (!SkIsAlign2(bounds.fLeft) || !SkIsAlign2(bounds.fTop)) { |
| return kInvalidParameters; |
| } |
| |
| #ifdef SK_DEBUG |
| { |
| // Make a copy, since getValidSubset can change its input. |
| SkIRect subset(bounds); |
| // That said, getValidSubset should *not* change its input, in this case; otherwise |
| // getValidSubset does not match the actual subsets we can do. |
| SkASSERT(this->getValidSubset(&subset) && subset == bounds); |
| } |
| #endif |
| |
| config.options.use_cropping = 1; |
| config.options.crop_left = bounds.fLeft; |
| config.options.crop_top = bounds.fTop; |
| config.options.crop_width = bounds.width(); |
| config.options.crop_height = bounds.height(); |
| } |
| |
| SkISize dstDimensions = dstInfo.dimensions(); |
| if (bounds.size() != dstDimensions) { |
| // Caller is requesting scaling. |
| config.options.use_scaling = 1; |
| config.options.scaled_width = dstDimensions.width(); |
| config.options.scaled_height = dstDimensions.height(); |
| } |
| |
| // FIXME (msarett): |
| // Lossless webp is encoded as BGRA. In that case, it would be more efficient to |
| // to decode BGRA and apply the color xform to a BGRA buffer. |
| config.output.colorspace = colorXform ? MODE_RGBA : |
| webp_decode_mode(dstInfo.colorType(), dstInfo.alphaType() == kPremul_SkAlphaType); |
| config.output.is_external_memory = 1; |
| |
| // 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 in the F16 case, |
| // where we need to allocate an extra image-sized buffer. |
| SkAutoTMalloc<uint32_t> pixels; |
| if (kRGBA_F16_SkColorType == dstInfo.colorType()) { |
| pixels.reset(dstDimensions.width() * dstDimensions.height()); |
| config.output.u.RGBA.rgba = (uint8_t*) pixels.get(); |
| config.output.u.RGBA.stride = (int) dstDimensions.width() * sizeof(uint32_t); |
| config.output.u.RGBA.size = config.output.u.RGBA.stride * dstDimensions.height(); |
| } else { |
| config.output.u.RGBA.rgba = (uint8_t*) dst; |
| config.output.u.RGBA.stride = (int) rowBytes; |
| config.output.u.RGBA.size = dstInfo.getSafeSize(rowBytes); |
| } |
| |
| WebPIterator frame; |
| SkAutoTCallVProc<WebPIterator, WebPDemuxReleaseIterator> autoFrame(&frame); |
| // If this succeeded in NewFromStream(), it should succeed again here. |
| SkAssertResult(WebPDemuxGetFrame(fDemux, 1, &frame)); |
| |
| SkAutoTCallVProc<WebPIDecoder, WebPIDelete> 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 = dstInfo.height(); |
| result = kSuccess; |
| break; |
| case VP8_STATUS_SUSPENDED: |
| WebPIDecGetRGB(idec, rowsDecodedPtr, nullptr, nullptr, nullptr); |
| rowsDecoded = *rowsDecodedPtr; |
| result = kIncompleteInput; |
| break; |
| default: |
| return kInvalidInput; |
| } |
| |
| if (colorXform) { |
| SkColorSpaceXform::ColorFormat colorFormat = select_xform_format(dstInfo.colorType()); |
| SkAlphaType xformAlphaType = select_xform_alpha(dstInfo.alphaType(), |
| this->getInfo().alphaType()); |
| |
| uint32_t* src = (uint32_t*) config.output.u.RGBA.rgba; |
| size_t srcRowBytes = config.output.u.RGBA.stride; |
| for (int y = 0; y < rowsDecoded; y++) { |
| colorXform->apply(dst, src, dstInfo.width(), colorFormat, xformAlphaType); |
| dst = SkTAddOffset<void>(dst, rowBytes); |
| src = SkTAddOffset<uint32_t>(src, srcRowBytes); |
| } |
| } |
| |
| return result; |
| } |
| |
| SkWebpCodec::SkWebpCodec(int width, int height, const SkEncodedInfo& info, |
| sk_sp<SkColorSpace> colorSpace, SkStream* stream, WebPDemuxer* demux, |
| sk_sp<SkData> data) |
| : INHERITED(width, height, info, stream, std::move(colorSpace)) |
| , fDemux(demux) |
| , fData(std::move(data)) |
| {} |