diff options
| -rw-r--r-- | dm/DMSrcSink.cpp | 7 | ||||
| -rw-r--r-- | src/codec/SkGifCodec.cpp | 42 | ||||
| -rw-r--r-- | third_party/gif/SkGifImageReader.cpp | 39 | ||||
| -rw-r--r-- | third_party/gif/SkGifImageReader.h | 5 |
4 files changed, 75 insertions, 18 deletions
diff --git a/dm/DMSrcSink.cpp b/dm/DMSrcSink.cpp index 30185a2ab1..4b297c1e10 100644 --- a/dm/DMSrcSink.cpp +++ b/dm/DMSrcSink.cpp @@ -473,6 +473,13 @@ Error CodecSrc::draw(SkCanvas* canvas) const { } break; } + case SkCodec::kInvalidConversion: + if (i > 0 && (decodeInfo.colorType() == kRGB_565_SkColorType + || decodeInfo.colorType() == kIndex_8_SkColorType)) { + return Error::Nonfatal(SkStringPrintf( + "Cannot decode frame %i to 565/Index8 (%s).", i, fPath.c_str())); + } + // Fall through. default: return SkStringPrintf("Couldn't getPixels for frame %i in %s.", i, fPath.c_str()); diff --git a/src/codec/SkGifCodec.cpp b/src/codec/SkGifCodec.cpp index 876d71f553..cb36cbf464 100644 --- a/src/codec/SkGifCodec.cpp +++ b/src/codec/SkGifCodec.cpp @@ -175,15 +175,37 @@ SkCodec::Result SkGifCodec::prepareToDecode(const SkImageInfo& dstInfo, SkPMColo } const size_t frameIndex = opts.fFrameIndex; - if (frameIndex > 0 && dstInfo.colorType() == kIndex_8_SkColorType) { - // FIXME: It is possible that a later frame can be decoded to index8, if it does one of the - // following: - // - Covers the entire previous frame - // - Shares a color table (and transparent index) with any prior frames that are showing. - // We must support index8 for the first frame to be backwards compatible on Android, but - // we do not (currently) need to support later frames as index8. - return gif_error("Cannot decode multiframe gif (except frame 0) as index 8.\n", - kInvalidConversion); + if (frameIndex > 0) { + switch (dstInfo.colorType()) { + case kIndex_8_SkColorType: + // FIXME: It is possible that a later frame can be decoded to index8, if it does one + // of the following: + // - Covers the entire previous frame + // - Shares a color table (and transparent index) with any prior frames that are + // showing. + // We must support index8 for the first frame to be backwards compatible on Android, + // but we do not (currently) need to support later frames as index8. + return gif_error("Cannot decode multiframe gif (except frame 0) as index 8.\n", + kInvalidConversion); + case kRGB_565_SkColorType: + // FIXME: In theory, we might be able to support this, but it's not clear that it + // is necessary (Chromium does not decode to 565, and Android does not decode + // frames beyond the first). Disabling it because it is somewhat difficult: + // - If there is a transparent pixel, and this frame draws on top of another frame + // (if the frame is independent with a transparent pixel, we should not decode to + // 565 anyway, since it is not opaque), we need to skip drawing the transparent + // pixels (see writeTransparentPixels in haveDecodedRow). We currently do this by + // first swizzling into temporary memory, then copying into the destination. (We + // let the swizzler handle it first because it may need to sample.) After + // swizzling to 565, we do not know which pixels in our temporary memory + // correspond to the transparent pixel, so we do not know what to skip. We could + // special case the non-sampled case (no need to swizzle), but as this is + // currently unused we can just not support it. + return gif_error("Cannot decode multiframe gif (except frame 0) as 565.\n", + kInvalidConversion); + default: + break; + } } fReader->parse((SkGifImageReader::SkGIFParseQuery) frameIndex); @@ -489,7 +511,7 @@ bool SkGifCodec::haveDecodedRow(size_t frameIndex, const unsigned char* rowBegin // we must write these for passes beyond the first, or the initial passes // will "show through" the later ones. const auto dstInfo = this->dstInfo(); - if (writeTransparentPixels || dstInfo.colorType() == kRGB_565_SkColorType) { + if (writeTransparentPixels) { fSwizzler->swizzle(dstLine, rowBegin); } else { // We cannot swizzle directly into the dst, since that will write the transparent pixels. diff --git a/third_party/gif/SkGifImageReader.cpp b/third_party/gif/SkGifImageReader.cpp index c40c27203e..eeaee68c1d 100644 --- a/third_party/gif/SkGifImageReader.cpp +++ b/third_party/gif/SkGifImageReader.cpp @@ -361,7 +361,7 @@ sk_sp<SkColorTable> SkGifImageReader::getColorTable(SkColorType colorType, size_ // Perform decoding for this frame. frameComplete will be true if the entire frame is decoded. // Returns false if a decoding error occurred. This is a fatal error and causes the SkGifImageReader to set the "decode failed" flag. // Otherwise, either not enough data is available to decode further than before, or the new data has been decoded successfully; returns true in this case. -bool SkGIFFrameContext::decode(SkGifCodec* client, bool* frameComplete) +bool SkGIFFrameContext::decode(SkGifCodec* client, const SkGIFColorMap& globalMap, bool* frameComplete) { *frameComplete = false; if (!m_lzwContext) { @@ -370,7 +370,7 @@ bool SkGIFFrameContext::decode(SkGifCodec* client, bool* frameComplete) return true; m_lzwContext.reset(new SkGIFLZWContext(client, this)); - if (!m_lzwContext->prepareToDecode()) { + if (!m_lzwContext->prepareToDecode(globalMap)) { m_lzwContext.reset(); return false; } @@ -403,7 +403,7 @@ bool SkGifImageReader::decode(size_t frameIndex, bool* frameComplete) { SkGIFFrameContext* currentFrame = m_frames[frameIndex].get(); - return currentFrame->decode(m_client, frameComplete); + return currentFrame->decode(m_client, m_globalColorMap, frameComplete); } // Parse incoming GIF data stream into internal data structures. @@ -890,7 +890,7 @@ void SkGifImageReader::addFrameIfNecessary() } // FIXME: Move this method to close to doLZW(). -bool SkGIFLZWContext::prepareToDecode() +bool SkGIFLZWContext::prepareToDecode(const SkGIFColorMap& globalMap) { SkASSERT(m_frameContext->isDataSizeDefined() && m_frameContext->isHeaderDefined()); @@ -906,8 +906,35 @@ bool SkGIFLZWContext::prepareToDecode() datum = bits = 0; ipass = m_frameContext->interlaced() ? 1 : 0; irow = 0; - alwaysWriteTransparentPixels = !m_frameContext->interlaced() - && m_frameContext->getRequiredFrame() == SkCodec::kNone; + alwaysWriteTransparentPixels = false; + if (m_frameContext->getRequiredFrame() == SkCodec::kNone) { + if (!m_frameContext->interlaced()) { + alwaysWriteTransparentPixels = true; + } else { + // The frame is interlaced, so we do not want to write transparent + // pixels. But if there are no transparent pixels anyway, there is + // no harm in taking the alwaysWriteTransparentPixels path, which + // is faster, and it also supports 565. + // Since the frame is independent, it does not matter whether the + // frame is subset (nothing behind it needs to show through). So we + // only need to know whether there is a valid transparent pixel. + // This is a little counterintuitive - we want to "always write + // transparent pixels" if there ARE NO transparent pixels, so we + // check to see whether the pixel index is >= numColors. + const auto& localMap = m_frameContext->localColorMap(); + const auto trans = m_frameContext->transparentPixel(); + if (localMap.isDefined()) { + alwaysWriteTransparentPixels = trans >= localMap.numColors(); + } else { + // Note that if the map is not defined, the value of + // alwaysWriteTransparentPixels is meaningless, since without + // any color table, we will skip drawing entirely. + // FIXME: We could even skip calling prepareToDecode in that + // case, meaning we can SkASSERT(globalMap.isDefined()) + alwaysWriteTransparentPixels = trans >= globalMap.numColors(); + } + } + } // We want to know the longest sequence encodable by a dictionary with // SK_MAX_DICTIONARY_ENTRIES entries. If we ignore the need to encode the base diff --git a/third_party/gif/SkGifImageReader.h b/third_party/gif/SkGifImageReader.h index fee1a5f3c7..5936350681 100644 --- a/third_party/gif/SkGifImageReader.h +++ b/third_party/gif/SkGifImageReader.h @@ -86,6 +86,7 @@ enum SkGIFState { }; struct SkGIFFrameContext; +class SkGIFColorMap; // LZW decoder state machine. class SkGIFLZWContext final : public SkNoncopyable { @@ -108,7 +109,7 @@ public: , m_frameContext(frameContext) { } - bool prepareToDecode(); + bool prepareToDecode(const SkGIFColorMap& globalMap); bool outputRow(const unsigned char* rowBegin); bool doLZW(const unsigned char* block, size_t bytesInBlock); bool hasRemainingRows() { return SkToBool(rowsRemaining); } @@ -210,7 +211,7 @@ public: m_lzwBlocks.push_back(SkData::MakeWithCopy(data, size)); } - bool decode(SkGifCodec* client, bool* frameDecoded); + bool decode(SkGifCodec* client, const SkGIFColorMap& globalMap, bool* frameDecoded); int frameId() const { return m_frameId; } void setRect(unsigned x, unsigned y, unsigned width, unsigned height) |