| /* |
| * Copyright 2015 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| /* |
| * Copyright (C) 2006 Apple Computer, Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY |
| * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR |
| * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY |
| * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "SkCodecAnimation.h" |
| #include "SkCodecPriv.h" |
| #include "SkColorPriv.h" |
| #include "SkColorTable.h" |
| #include "SkGifCodec.h" |
| #include "SkStream.h" |
| #include "SkSwizzler.h" |
| |
| #include <algorithm> |
| |
| #define GIF87_STAMP "GIF87a" |
| #define GIF89_STAMP "GIF89a" |
| #define GIF_STAMP_LEN 6 |
| |
| /* |
| * Checks the start of the stream to see if the image is a gif |
| */ |
| bool SkGifCodec::IsGif(const void* buf, size_t bytesRead) { |
| if (bytesRead >= GIF_STAMP_LEN) { |
| if (memcmp(GIF87_STAMP, buf, GIF_STAMP_LEN) == 0 || |
| memcmp(GIF89_STAMP, buf, GIF_STAMP_LEN) == 0) |
| { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /* |
| * Error function |
| */ |
| static SkCodec::Result gif_error(const char* msg, SkCodec::Result result = SkCodec::kInvalidInput) { |
| SkCodecPrintf("Gif Error: %s\n", msg); |
| return result; |
| } |
| |
| /* |
| * Assumes IsGif was called and returned true |
| * Creates a gif decoder |
| * Reads enough of the stream to determine the image format |
| */ |
| SkCodec* SkGifCodec::NewFromStream(SkStream* stream) { |
| std::unique_ptr<SkGifImageReader> reader(new SkGifImageReader(stream)); |
| if (!reader->parse(SkGifImageReader::SkGIFSizeQuery)) { |
| // Fatal error occurred. |
| return nullptr; |
| } |
| |
| // If no images are in the data, or the first header is not yet defined, we cannot |
| // create a codec. In either case, the width and height are not yet known. |
| if (0 == reader->imagesCount() || !reader->frameContext(0)->isHeaderDefined()) { |
| return nullptr; |
| } |
| |
| // isHeaderDefined() will not return true if the screen size is empty. |
| SkASSERT(reader->screenHeight() > 0 && reader->screenWidth() > 0); |
| |
| const auto alpha = reader->firstFrameHasAlpha() ? SkEncodedInfo::kBinary_Alpha |
| : SkEncodedInfo::kOpaque_Alpha; |
| // Use kPalette since Gifs are encoded with a color table. |
| // FIXME: Gifs can actually be encoded with 4-bits per pixel. Using 8 works, but we could skip |
| // expanding to 8 bits and take advantage of the SkSwizzler to work from 4. |
| const auto encodedInfo = SkEncodedInfo::Make(SkEncodedInfo::kPalette_Color, alpha, 8); |
| |
| // Although the encodedInfo is always kPalette_Color, it is possible that kIndex_8 is |
| // unsupported if the frame is subset and there is no transparent pixel. |
| const auto colorType = reader->firstFrameSupportsIndex8() ? kIndex_8_SkColorType |
| : kN32_SkColorType; |
| // The choice of unpremul versus premul is arbitrary, since all colors are either fully |
| // opaque or fully transparent (i.e. kBinary), but we stored the transparent colors as all |
| // zeroes, which is arguably premultiplied. |
| const auto alphaType = reader->firstFrameHasAlpha() ? kUnpremul_SkAlphaType |
| : kOpaque_SkAlphaType; |
| |
| const auto imageInfo = SkImageInfo::Make(reader->screenWidth(), reader->screenHeight(), |
| colorType, alphaType, |
| SkColorSpace::MakeNamed(SkColorSpace::kSRGB_Named)); |
| return new SkGifCodec(encodedInfo, imageInfo, reader.release()); |
| } |
| |
| bool SkGifCodec::onRewind() { |
| fReader->clearDecodeState(); |
| return true; |
| } |
| |
| SkGifCodec::SkGifCodec(const SkEncodedInfo& encodedInfo, const SkImageInfo& imageInfo, |
| SkGifImageReader* reader) |
| : INHERITED(encodedInfo, imageInfo, nullptr) |
| , fReader(reader) |
| , fTmpBuffer(nullptr) |
| , fSwizzler(nullptr) |
| , fCurrColorTable(nullptr) |
| , fCurrColorTableIsReal(false) |
| , fFilledBackground(false) |
| , fFirstCallToIncrementalDecode(false) |
| , fDst(nullptr) |
| , fDstRowBytes(0) |
| , fRowsDecoded(0) |
| { |
| reader->setClient(this); |
| } |
| |
| std::vector<SkCodec::FrameInfo> SkGifCodec::onGetFrameInfo() { |
| fReader->parse(SkGifImageReader::SkGIFFrameCountQuery); |
| const size_t size = fReader->imagesCount(); |
| std::vector<FrameInfo> result(size); |
| for (size_t i = 0; i < size; i++) { |
| const SkGIFFrameContext* frameContext = fReader->frameContext(i); |
| result[i].fDuration = frameContext->delayTime(); |
| result[i].fRequiredFrame = frameContext->getRequiredFrame(); |
| result[i].fFullyReceived = frameContext->isComplete(); |
| } |
| return result; |
| } |
| |
| int SkGifCodec::onGetRepetitionCount() { |
| fReader->parse(SkGifImageReader::SkGIFLoopCountQuery); |
| return fReader->loopCount(); |
| } |
| |
| static const SkColorType kXformSrcColorType = kRGBA_8888_SkColorType; |
| |
| void SkGifCodec::initializeColorTable(const SkImageInfo& dstInfo, size_t frameIndex) { |
| SkColorType colorTableColorType = dstInfo.colorType(); |
| if (this->colorXform()) { |
| colorTableColorType = kXformSrcColorType; |
| } |
| |
| sk_sp<SkColorTable> currColorTable = fReader->getColorTable(colorTableColorType, frameIndex); |
| fCurrColorTableIsReal = currColorTable; |
| if (!fCurrColorTableIsReal) { |
| // This is possible for an empty frame. Create a dummy with one value (transparent). |
| SkPMColor color = SK_ColorTRANSPARENT; |
| fCurrColorTable.reset(new SkColorTable(&color, 1)); |
| } else if (this->colorXform() && !fXformOnDecode) { |
| SkPMColor dstColors[256]; |
| const SkColorSpaceXform::ColorFormat dstFormat = select_xform_format(dstInfo.colorType()); |
| const SkColorSpaceXform::ColorFormat srcFormat = select_xform_format(kXformSrcColorType); |
| const SkAlphaType xformAlphaType = select_xform_alpha(dstInfo.alphaType(), |
| this->getInfo().alphaType()); |
| SkAssertResult(this->colorXform()->apply(dstFormat, dstColors, srcFormat, |
| currColorTable->readColors(), |
| currColorTable->count(), xformAlphaType)); |
| fCurrColorTable.reset(new SkColorTable(dstColors, currColorTable->count())); |
| } else { |
| fCurrColorTable = std::move(currColorTable); |
| } |
| } |
| |
| |
| SkCodec::Result SkGifCodec::prepareToDecode(const SkImageInfo& dstInfo, SkPMColor* inputColorPtr, |
| int* inputColorCount, const Options& opts) { |
| // Check for valid input parameters |
| if (!conversion_possible(dstInfo, this->getInfo()) || !this->initializeColorXform(dstInfo)) { |
| return gif_error("Cannot convert input type to output type.\n", kInvalidConversion); |
| } |
| |
| fXformOnDecode = false; |
| if (this->colorXform()) { |
| fXformOnDecode = apply_xform_on_decode(dstInfo.colorType(), this->getEncodedInfo().color()); |
| if (fXformOnDecode) { |
| fXformBuffer.reset(new uint32_t[dstInfo.width()]); |
| sk_bzero(fXformBuffer.get(), dstInfo.width() * sizeof(uint32_t)); |
| } |
| } |
| |
| if (opts.fSubset) { |
| return gif_error("Subsets not supported.\n", kUnimplemented); |
| } |
| |
| const size_t frameIndex = opts.fFrameIndex; |
| 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); |
| |
| if (frameIndex >= fReader->imagesCount()) { |
| return gif_error("frame index out of range!\n", kIncompleteInput); |
| } |
| |
| auto& localMap = fReader->frameContext(frameIndex)->localColorMap(); |
| if (localMap.numColors() && !localMap.isDefined()) { |
| // We have parsed enough to know that there is a color map, but cannot |
| // parse the map itself yet. Exit now, so we do not build an incorrect |
| // table. |
| return gif_error("color map not available yet\n", kIncompleteInput); |
| } |
| |
| fTmpBuffer.reset(new uint8_t[dstInfo.minRowBytes()]); |
| |
| this->initializeColorTable(dstInfo, frameIndex); |
| this->initializeSwizzler(dstInfo, frameIndex); |
| |
| SkASSERT(fCurrColorTable); |
| if (inputColorCount) { |
| *inputColorCount = fCurrColorTable->count(); |
| } |
| copy_color_table(dstInfo, fCurrColorTable.get(), inputColorPtr, inputColorCount); |
| |
| return kSuccess; |
| } |
| |
| void SkGifCodec::initializeSwizzler(const SkImageInfo& dstInfo, size_t frameIndex) { |
| const SkGIFFrameContext* frame = fReader->frameContext(frameIndex); |
| // This is only called by prepareToDecode, which ensures frameIndex is in range. |
| SkASSERT(frame); |
| |
| const int xBegin = frame->xOffset(); |
| const int xEnd = std::min(static_cast<int>(frame->xOffset() + frame->width()), |
| static_cast<int>(fReader->screenWidth())); |
| |
| // CreateSwizzler only reads left and right of the frame. We cannot use the frame's raw |
| // frameRect, since it might extend beyond the edge of the frame. |
| SkIRect swizzleRect = SkIRect::MakeLTRB(xBegin, 0, xEnd, 0); |
| |
| SkImageInfo swizzlerInfo = dstInfo; |
| if (this->colorXform()) { |
| swizzlerInfo = swizzlerInfo.makeColorType(kXformSrcColorType); |
| if (kPremul_SkAlphaType == dstInfo.alphaType()) { |
| swizzlerInfo = swizzlerInfo.makeAlphaType(kUnpremul_SkAlphaType); |
| } |
| } |
| |
| // The default Options should be fine: |
| // - we'll ignore if the memory is zero initialized - unless we're the first frame, this won't |
| // matter anyway. |
| // - subsets are not supported for gif |
| // - the swizzler does not need to know about the frame. |
| // We may not be able to use the real Options anyway, since getPixels does not store it (due to |
| // a bug). |
| fSwizzler.reset(SkSwizzler::CreateSwizzler(this->getEncodedInfo(), |
| fCurrColorTable->readColors(), swizzlerInfo, Options(), &swizzleRect)); |
| SkASSERT(fSwizzler.get()); |
| } |
| |
| /* |
| * Initiates the gif decode |
| */ |
| SkCodec::Result SkGifCodec::onGetPixels(const SkImageInfo& dstInfo, |
| void* pixels, size_t dstRowBytes, |
| const Options& opts, |
| SkPMColor* inputColorPtr, |
| int* inputColorCount, |
| int* rowsDecoded) { |
| Result result = this->prepareToDecode(dstInfo, inputColorPtr, inputColorCount, opts); |
| switch (result) { |
| case kSuccess: |
| break; |
| case kIncompleteInput: |
| // onStartIncrementalDecode treats this as incomplete, since it may |
| // provide more data later, but in this case, no more data will be |
| // provided, and there is nothing to draw. We also cannot return |
| // kIncompleteInput, which will make SkCodec attempt to fill |
| // remaining rows, but that requires an SkSwizzler, which we have |
| // not created. |
| return kInvalidInput; |
| default: |
| return result; |
| } |
| |
| if (dstInfo.dimensions() != this->getInfo().dimensions()) { |
| return gif_error("Scaling not supported.\n", kInvalidScale); |
| } |
| |
| fDst = pixels; |
| fDstRowBytes = dstRowBytes; |
| |
| return this->decodeFrame(true, opts, rowsDecoded); |
| } |
| |
| SkCodec::Result SkGifCodec::onStartIncrementalDecode(const SkImageInfo& dstInfo, |
| void* pixels, size_t dstRowBytes, |
| const SkCodec::Options& opts, |
| SkPMColor* inputColorPtr, |
| int* inputColorCount) { |
| Result result = this->prepareToDecode(dstInfo, inputColorPtr, inputColorCount, opts); |
| if (result != kSuccess) { |
| return result; |
| } |
| |
| fDst = pixels; |
| fDstRowBytes = dstRowBytes; |
| |
| fFirstCallToIncrementalDecode = true; |
| |
| return kSuccess; |
| } |
| |
| SkCodec::Result SkGifCodec::onIncrementalDecode(int* rowsDecoded) { |
| // It is possible the client has appended more data. Parse, if needed. |
| const auto& options = this->options(); |
| const size_t frameIndex = options.fFrameIndex; |
| fReader->parse((SkGifImageReader::SkGIFParseQuery) frameIndex); |
| |
| const bool firstCallToIncrementalDecode = fFirstCallToIncrementalDecode; |
| fFirstCallToIncrementalDecode = false; |
| return this->decodeFrame(firstCallToIncrementalDecode, options, rowsDecoded); |
| } |
| |
| SkCodec::Result SkGifCodec::decodeFrame(bool firstAttempt, const Options& opts, int* rowsDecoded) { |
| const SkImageInfo& dstInfo = this->dstInfo(); |
| const size_t frameIndex = opts.fFrameIndex; |
| SkASSERT(frameIndex < fReader->imagesCount()); |
| const SkGIFFrameContext* frameContext = fReader->frameContext(frameIndex); |
| if (firstAttempt) { |
| // rowsDecoded reports how many rows have been initialized, so a layer above |
| // can fill the rest. In some cases, we fill the background before decoding |
| // (or it is already filled for us), so we report rowsDecoded to be the full |
| // height. |
| bool filledBackground = false; |
| if (frameContext->getRequiredFrame() == kNone) { |
| // We may need to clear to transparent for one of the following reasons: |
| // - The frameRect does not cover the full bounds. haveDecodedRow will |
| // only draw inside the frameRect, so we need to clear the rest. |
| // - The frame is interlaced. There is no obvious way to fill |
| // afterwards for an incomplete image. (FIXME: Does the first pass |
| // cover all rows? If so, we do not have to fill here.) |
| // - There is no color table for this frame. In that case will not |
| // draw anything, so we need to fill. |
| if (frameContext->frameRect() != this->getInfo().bounds() |
| || frameContext->interlaced() || !fCurrColorTableIsReal) { |
| // fill ignores the width (replaces it with the actual, scaled width). |
| // But we need to scale in Y. |
| const int scaledHeight = get_scaled_dimension(dstInfo.height(), |
| fSwizzler->sampleY()); |
| auto fillInfo = dstInfo.makeWH(0, scaledHeight); |
| fSwizzler->fill(fillInfo, fDst, fDstRowBytes, this->getFillValue(dstInfo), |
| opts.fZeroInitialized); |
| filledBackground = true; |
| } |
| } else { |
| // Not independent |
| if (!opts.fHasPriorFrame) { |
| // Decode that frame into pixels. |
| Options prevFrameOpts(opts); |
| prevFrameOpts.fFrameIndex = frameContext->getRequiredFrame(); |
| prevFrameOpts.fHasPriorFrame = false; |
| // The prior frame may have a different color table, so update it and the |
| // swizzler. |
| this->initializeColorTable(dstInfo, prevFrameOpts.fFrameIndex); |
| this->initializeSwizzler(dstInfo, prevFrameOpts.fFrameIndex); |
| |
| const Result prevResult = this->decodeFrame(true, prevFrameOpts, nullptr); |
| switch (prevResult) { |
| case kSuccess: |
| // Prior frame succeeded. Carry on. |
| break; |
| case kIncompleteInput: |
| // Prior frame was incomplete. So this frame cannot be decoded. |
| return kInvalidInput; |
| default: |
| return prevResult; |
| } |
| |
| // Go back to using the correct color table for this frame. |
| this->initializeColorTable(dstInfo, frameIndex); |
| this->initializeSwizzler(dstInfo, frameIndex); |
| } |
| const auto* prevFrame = fReader->frameContext(frameContext->getRequiredFrame()); |
| if (prevFrame->getDisposalMethod() == SkCodecAnimation::RestoreBGColor_DisposalMethod) { |
| SkIRect prevRect = prevFrame->frameRect(); |
| if (prevRect.intersect(this->getInfo().bounds())) { |
| // Do the divide ourselves for left and top, since we do not want |
| // get_scaled_dimension to upgrade 0 to 1. (This is similar to SkSampledCodec's |
| // sampling of the subset.) |
| auto left = prevRect.fLeft / fSwizzler->sampleX(); |
| auto top = prevRect.fTop / fSwizzler->sampleY(); |
| void* const eraseDst = SkTAddOffset<void>(fDst, top * fDstRowBytes |
| + left * SkColorTypeBytesPerPixel(dstInfo.colorType())); |
| auto width = get_scaled_dimension(prevRect.width(), fSwizzler->sampleX()); |
| auto height = get_scaled_dimension(prevRect.height(), fSwizzler->sampleY()); |
| // fSwizzler->fill() would fill to the scaled width of the frame, but we want to |
| // fill to the scaled with of the width of the PRIOR frame, so we do all the |
| // scaling ourselves and call the static version. |
| SkSampler::Fill(dstInfo.makeWH(width, height), eraseDst, |
| fDstRowBytes, this->getFillValue(dstInfo), kNo_ZeroInitialized); |
| } |
| } |
| filledBackground = true; |
| } |
| |
| fFilledBackground = filledBackground; |
| if (filledBackground) { |
| // Report the full (scaled) height, since the client will never need to fill. |
| fRowsDecoded = get_scaled_dimension(dstInfo.height(), fSwizzler->sampleY()); |
| } else { |
| // This will be updated by haveDecodedRow. |
| fRowsDecoded = 0; |
| } |
| } |
| |
| if (!fCurrColorTableIsReal) { |
| // Nothing to draw this frame. |
| return kSuccess; |
| } |
| |
| // Note: there is a difference between the following call to SkGifImageReader::decode |
| // returning false and leaving frameDecoded false: |
| // - If the method returns false, there was an error in the stream. We still treat this as |
| // incomplete, since we have already decoded some rows. |
| // - If frameDecoded is false, that just means that we do not have enough data. If more data |
| // is supplied, we may be able to continue decoding this frame. We also treat this as |
| // incomplete. |
| // FIXME: Ensure that we do not attempt to continue decoding if the method returns false and |
| // more data is supplied. |
| bool frameDecoded = false; |
| if (!fReader->decode(frameIndex, &frameDecoded) || !frameDecoded) { |
| if (rowsDecoded) { |
| *rowsDecoded = fRowsDecoded; |
| } |
| return kIncompleteInput; |
| } |
| |
| return kSuccess; |
| } |
| |
| uint64_t SkGifCodec::onGetFillValue(const SkImageInfo& dstInfo) const { |
| // Note: Using fCurrColorTable relies on having called initializeColorTable already. |
| // This is (currently) safe because this method is only called when filling, after |
| // initializeColorTable has been called. |
| // FIXME: Is there a way to make this less fragile? |
| if (dstInfo.colorType() == kIndex_8_SkColorType && fCurrColorTableIsReal) { |
| // We only support index 8 for the first frame, for backwards |
| // compatibity on Android, so we are using the color table for the first frame. |
| SkASSERT(this->options().fFrameIndex == 0); |
| // Use the transparent index for the first frame. |
| const size_t transPixel = fReader->frameContext(0)->transparentPixel(); |
| if (transPixel < (size_t) fCurrColorTable->count()) { |
| return transPixel; |
| } |
| // Fall through to return SK_ColorTRANSPARENT (i.e. 0). This choice is arbitrary, |
| // but we have to pick something inside the color table, and this one is as good |
| // as any. |
| } |
| // Using transparent as the fill value matches the behavior in Chromium, |
| // which ignores the background color. |
| // If the colorType is kIndex_8, and there was no color table (i.e. |
| // fCurrColorTableIsReal is false), this value (zero) corresponds to the |
| // only entry in the dummy color table provided to the client. |
| return SK_ColorTRANSPARENT; |
| } |
| |
| void SkGifCodec::applyXformRow(const SkImageInfo& dstInfo, void* dst, const uint8_t* src) const { |
| if (this->colorXform() && fXformOnDecode) { |
| fSwizzler->swizzle(fXformBuffer.get(), src); |
| |
| const SkColorSpaceXform::ColorFormat dstFormat = select_xform_format(dstInfo.colorType()); |
| const SkColorSpaceXform::ColorFormat srcFormat = select_xform_format(kXformSrcColorType); |
| const SkAlphaType xformAlphaType = select_xform_alpha(dstInfo.alphaType(), |
| this->getInfo().alphaType()); |
| const int xformWidth = get_scaled_dimension(dstInfo.width(), fSwizzler->sampleX()); |
| SkAssertResult(this->colorXform()->apply(dstFormat, dst, srcFormat, fXformBuffer.get(), |
| xformWidth, xformAlphaType)); |
| } else { |
| fSwizzler->swizzle(dst, src); |
| } |
| } |
| |
| bool SkGifCodec::haveDecodedRow(size_t frameIndex, const unsigned char* rowBegin, |
| size_t rowNumber, unsigned repeatCount, bool writeTransparentPixels) |
| { |
| const SkGIFFrameContext* frameContext = fReader->frameContext(frameIndex); |
| // The pixel data and coordinates supplied to us are relative to the frame's |
| // origin within the entire image size, i.e. |
| // (frameContext->xOffset, frameContext->yOffset). There is no guarantee |
| // that width == (size().width() - frameContext->xOffset), so |
| // we must ensure we don't run off the end of either the source data or the |
| // row's X-coordinates. |
| const size_t width = frameContext->width(); |
| const int xBegin = frameContext->xOffset(); |
| const int yBegin = frameContext->yOffset() + rowNumber; |
| const int xEnd = std::min(static_cast<int>(frameContext->xOffset() + width), |
| this->getInfo().width()); |
| const int yEnd = std::min(static_cast<int>(frameContext->yOffset() + rowNumber + repeatCount), |
| this->getInfo().height()); |
| // FIXME: No need to make the checks on width/xBegin/xEnd for every row. We could instead do |
| // this once in prepareToDecode. |
| if (!width || (xBegin < 0) || (yBegin < 0) || (xEnd <= xBegin) || (yEnd <= yBegin)) |
| return true; |
| |
| // yBegin is the first row in the non-sampled image. dstRow will be the row in the output, |
| // after potentially scaling it. |
| int dstRow = yBegin; |
| |
| const int sampleY = fSwizzler->sampleY(); |
| if (sampleY > 1) { |
| // Check to see whether this row or one that falls in the repeatCount is needed in the |
| // output. |
| bool foundNecessaryRow = false; |
| for (unsigned i = 0; i < repeatCount; i++) { |
| const int potentialRow = yBegin + i; |
| if (fSwizzler->rowNeeded(potentialRow)) { |
| dstRow = potentialRow / sampleY; |
| const int scaledHeight = get_scaled_dimension(this->dstInfo().height(), sampleY); |
| if (dstRow >= scaledHeight) { |
| return true; |
| } |
| |
| foundNecessaryRow = true; |
| repeatCount -= i; |
| |
| repeatCount = (repeatCount - 1) / sampleY + 1; |
| |
| // Make sure the repeatCount does not take us beyond the end of the dst |
| if (dstRow + (int) repeatCount > scaledHeight) { |
| repeatCount = scaledHeight - dstRow; |
| SkASSERT(repeatCount >= 1); |
| } |
| break; |
| } |
| } |
| |
| if (!foundNecessaryRow) { |
| return true; |
| } |
| } else { |
| // Make sure the repeatCount does not take us beyond the end of the dst |
| SkASSERT(this->dstInfo().height() >= yBegin); |
| repeatCount = SkTMin(repeatCount, (unsigned) (this->dstInfo().height() - yBegin)); |
| } |
| |
| if (!fFilledBackground) { |
| // At this point, we are definitely going to write the row, so count it towards the number |
| // of rows decoded. |
| // We do not consider the repeatCount, which only happens for interlaced, in which case we |
| // have already set fRowsDecoded to the proper value (reflecting that we have filled the |
| // background). |
| fRowsDecoded++; |
| } |
| |
| // decodeFrame will early exit if this is false, so this method will not be |
| // called. |
| SkASSERT(fCurrColorTableIsReal); |
| |
| // The swizzler takes care of offsetting into the dst width-wise. |
| void* dstLine = SkTAddOffset<void>(fDst, dstRow * fDstRowBytes); |
| |
| // We may or may not need to write transparent pixels to the buffer. |
| // If we're compositing against a previous image, it's wrong, but if |
| // we're decoding an interlaced gif and displaying it "Haeberli"-style, |
| // 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) { |
| this->applyXformRow(dstInfo, dstLine, rowBegin); |
| } else { |
| sk_bzero(fTmpBuffer.get(), dstInfo.minRowBytes()); |
| this->applyXformRow(dstInfo, fTmpBuffer.get(), rowBegin); |
| |
| const size_t offsetBytes = fSwizzler->swizzleOffsetBytes(); |
| switch (dstInfo.colorType()) { |
| case kBGRA_8888_SkColorType: |
| case kRGBA_8888_SkColorType: { |
| uint32_t* dstPixel = SkTAddOffset<uint32_t>(dstLine, offsetBytes); |
| uint32_t* srcPixel = SkTAddOffset<uint32_t>(fTmpBuffer.get(), offsetBytes); |
| for (int i = 0; i < fSwizzler->swizzleWidth(); i++) { |
| // Technically SK_ColorTRANSPARENT is an SkPMColor, and srcPixel would have |
| // the opposite swizzle for the non-native swizzle, but TRANSPARENT is all |
| // zeroes, which is the same either way. |
| if (*srcPixel != SK_ColorTRANSPARENT) { |
| *dstPixel = *srcPixel; |
| } |
| dstPixel++; |
| srcPixel++; |
| } |
| break; |
| } |
| case kRGBA_F16_SkColorType: { |
| uint64_t* dstPixel = SkTAddOffset<uint64_t>(dstLine, offsetBytes); |
| uint64_t* srcPixel = SkTAddOffset<uint64_t>(fTmpBuffer.get(), offsetBytes); |
| for (int i = 0; i < fSwizzler->swizzleWidth(); i++) { |
| if (*srcPixel != 0) { |
| *dstPixel = *srcPixel; |
| } |
| dstPixel++; |
| srcPixel++; |
| } |
| break; |
| } |
| default: |
| SkASSERT(false); |
| break; |
| } |
| } |
| |
| // Tell the frame to copy the row data if need be. |
| if (repeatCount > 1) { |
| const size_t bytesPerPixel = SkColorTypeBytesPerPixel(this->dstInfo().colorType()); |
| const size_t bytesToCopy = fSwizzler->swizzleWidth() * bytesPerPixel; |
| void* copiedLine = SkTAddOffset<void>(dstLine, fSwizzler->swizzleOffsetBytes()); |
| void* dst = copiedLine; |
| for (unsigned i = 1; i < repeatCount; i++) { |
| dst = SkTAddOffset<void>(dst, fDstRowBytes); |
| memcpy(dst, copiedLine, bytesToCopy); |
| } |
| } |
| |
| return true; |
| } |