| // Copyright 2015 Google Inc. |
| // Use of this source code is governed by the BSD-3-Clause license that can be |
| // found in the LICENSE.md 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 "SkGifCodec.h" |
| #include "SkLibGifCodec.h" |
| |
| #include "include/codec/SkCodecAnimation.h" |
| #include "include/core/SkStream.h" |
| #include "include/private/SkColorData.h" |
| #include "src/codec/SkCodecPriv.h" |
| #include "src/codec/SkColorTable.h" |
| #include "src/codec/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; |
| } |
| |
| std::unique_ptr<SkCodec> SkGifCodec::MakeFromStream(std::unique_ptr<SkStream> stream, |
| SkCodec::Result* result) { |
| std::unique_ptr<SkGifImageReader> reader(new SkGifImageReader(std::move(stream))); |
| *result = reader->parse(SkGifImageReader::SkGIFSizeQuery); |
| if (*result != SkCodec::kSuccess) { |
| 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. |
| auto* frame = reader->frameContext(0); |
| if (!frame || !frame->isHeaderDefined()) { |
| *result = SkCodec::kInvalidInput; |
| 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. |
| auto encodedInfo = SkEncodedInfo::Make(reader->screenWidth(), reader->screenHeight(), |
| SkEncodedInfo::kPalette_Color, alpha, 8); |
| return std::unique_ptr<SkCodec>(new SkLibGifCodec(std::move(encodedInfo), reader.release())); |
| } |
| |
| bool SkLibGifCodec::onRewind() { |
| fReader->clearDecodeState(); |
| return true; |
| } |
| |
| SkLibGifCodec::SkLibGifCodec(SkEncodedInfo&& encodedInfo, SkGifImageReader* reader) |
| : INHERITED(std::move(encodedInfo), skcms_PixelFormat_RGBA_8888, nullptr) |
| , fReader(reader) |
| , fTmpBuffer(nullptr) |
| , fSwizzler(nullptr) |
| , fCurrColorTable(nullptr) |
| , fCurrColorTableIsReal(false) |
| , fFilledBackground(false) |
| , fFirstCallToIncrementalDecode(false) |
| , fDst(nullptr) |
| , fDstRowBytes(0) |
| , fRowsDecoded(0) |
| { |
| reader->setClient(this); |
| } |
| |
| int SkLibGifCodec::onGetFrameCount() { |
| fReader->parse(SkGifImageReader::SkGIFFrameCountQuery); |
| return fReader->imagesCount(); |
| } |
| |
| bool SkLibGifCodec::onGetFrameInfo(int i, SkCodec::FrameInfo* frameInfo) const { |
| if (i >= fReader->imagesCount()) { |
| return false; |
| } |
| |
| const SkGIFFrameContext* frameContext = fReader->frameContext(i); |
| SkASSERT(frameContext->reachedStartOfData()); |
| |
| if (frameInfo) { |
| frameContext->fillIn(frameInfo, frameContext->isComplete()); |
| |
| auto* rect = &frameInfo->fFrameRect; |
| auto bounds = this->bounds(); |
| if (!rect->intersect(bounds)) { |
| // If a frame is offscreen, it will have no effect on the output |
| // image. Modify its bounds to be consistent with the Wuffs |
| // implementation. |
| rect->setLTRB(std::min(rect->left(), bounds.right()), |
| std::min(rect->top(), bounds.bottom()), |
| std::min(rect->right(), bounds.right()), |
| std::min(rect->bottom(), bounds.bottom())); |
| } |
| } |
| return true; |
| } |
| |
| int SkLibGifCodec::onGetRepetitionCount() { |
| fReader->parse(SkGifImageReader::SkGIFLoopCountQuery); |
| return fReader->loopCount(); |
| } |
| |
| static constexpr SkColorType kXformSrcColorType = kRGBA_8888_SkColorType; |
| |
| void SkLibGifCodec::initializeColorTable(const SkImageInfo& dstInfo, int frameIndex) { |
| SkColorType colorTableColorType = dstInfo.colorType(); |
| if (this->colorXform()) { |
| colorTableColorType = kXformSrcColorType; |
| } |
| |
| sk_sp<SkColorTable> currColorTable = fReader->getColorTable(colorTableColorType, frameIndex); |
| fCurrColorTableIsReal = static_cast<bool>(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() && !this->xformOnDecode()) { |
| SkPMColor dstColors[256]; |
| this->applyColorXform(dstColors, currColorTable->readColors(), |
| currColorTable->count()); |
| fCurrColorTable.reset(new SkColorTable(dstColors, currColorTable->count())); |
| } else { |
| fCurrColorTable = std::move(currColorTable); |
| } |
| } |
| |
| |
| SkCodec::Result SkLibGifCodec::prepareToDecode(const SkImageInfo& dstInfo, const Options& opts) { |
| if (opts.fSubset) { |
| return gif_error("Subsets not supported.\n", kUnimplemented); |
| } |
| |
| const int frameIndex = opts.fFrameIndex; |
| if (frameIndex > 0 && kRGB_565_SkColorType == dstInfo.colorType()) { |
| // 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); |
| } |
| |
| const auto* frame = fReader->frameContext(frameIndex); |
| SkASSERT(frame); |
| if (0 == frameIndex) { |
| // SkCodec does not have a way to just parse through frame 0, so we |
| // have to do so manually, here. |
| fReader->parse((SkGifImageReader::SkGIFParseQuery) 0); |
| if (!frame->reachedStartOfData()) { |
| // 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); |
| } |
| } else { |
| // Parsing happened in SkCodec::getPixels. |
| SkASSERT(frameIndex < fReader->imagesCount()); |
| SkASSERT(frame->reachedStartOfData()); |
| } |
| |
| if (this->xformOnDecode()) { |
| fXformBuffer.reset(new uint32_t[dstInfo.width()]); |
| sk_bzero(fXformBuffer.get(), dstInfo.width() * sizeof(uint32_t)); |
| } |
| |
| fTmpBuffer.reset(new uint8_t[dstInfo.minRowBytes()]); |
| |
| this->initializeColorTable(dstInfo, frameIndex); |
| this->initializeSwizzler(dstInfo, frameIndex); |
| |
| SkASSERT(fCurrColorTable); |
| return kSuccess; |
| } |
| |
| void SkLibGifCodec::initializeSwizzler(const SkImageInfo& dstInfo, int 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(frame->frameRect().right(), 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 = SkSwizzler::Make(this->getEncodedInfo(), fCurrColorTable->readColors(), |
| swizzlerInfo, Options(), &swizzleRect); |
| SkASSERT(fSwizzler.get()); |
| } |
| |
| /* |
| * Initiates the gif decode |
| */ |
| SkCodec::Result SkLibGifCodec::onGetPixels(const SkImageInfo& dstInfo, |
| void* pixels, size_t dstRowBytes, |
| const Options& opts, |
| int* rowsDecoded) { |
| Result result = this->prepareToDecode(dstInfo, 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->dimensions()) { |
| return gif_error("Scaling not supported.\n", kInvalidScale); |
| } |
| |
| fDst = pixels; |
| fDstRowBytes = dstRowBytes; |
| |
| return this->decodeFrame(true, opts, rowsDecoded); |
| } |
| |
| SkCodec::Result SkLibGifCodec::onStartIncrementalDecode(const SkImageInfo& dstInfo, |
| void* pixels, size_t dstRowBytes, |
| const SkCodec::Options& opts) { |
| Result result = this->prepareToDecode(dstInfo, opts); |
| if (result != kSuccess) { |
| return result; |
| } |
| |
| fDst = pixels; |
| fDstRowBytes = dstRowBytes; |
| |
| fFirstCallToIncrementalDecode = true; |
| |
| return kSuccess; |
| } |
| |
| SkCodec::Result SkLibGifCodec::onIncrementalDecode(int* rowsDecoded) { |
| // It is possible the client has appended more data. Parse, if needed. |
| const auto& options = this->options(); |
| const int frameIndex = options.fFrameIndex; |
| fReader->parse((SkGifImageReader::SkGIFParseQuery) frameIndex); |
| |
| const bool firstCallToIncrementalDecode = fFirstCallToIncrementalDecode; |
| fFirstCallToIncrementalDecode = false; |
| return this->decodeFrame(firstCallToIncrementalDecode, options, rowsDecoded); |
| } |
| |
| SkCodec::Result SkLibGifCodec::decodeFrame(bool firstAttempt, const Options& opts, int* rowsDecoded) { |
| const SkImageInfo& dstInfo = this->dstInfo(); |
| const int scaledHeight = get_scaled_dimension(dstInfo.height(), fSwizzler->sampleY()); |
| |
| const int 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() == kNoFrame) { |
| // 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->bounds() |
| || frameContext->interlaced() || !fCurrColorTableIsReal) { |
| auto fillInfo = dstInfo.makeWH(fSwizzler->fillWidth(), scaledHeight); |
| SkSampler::Fill(fillInfo, fDst, fDstRowBytes, opts.fZeroInitialized); |
| filledBackground = true; |
| } |
| } else { |
| // Not independent. |
| // SkCodec ensured that the prior frame has been decoded. |
| filledBackground = true; |
| } |
| |
| fFilledBackground = filledBackground; |
| if (filledBackground) { |
| // Report the full (scaled) height, since the client will never need to fill. |
| fRowsDecoded = scaledHeight; |
| } else { |
| // This will be updated by haveDecodedRow. |
| fRowsDecoded = 0; |
| } |
| } |
| |
| if (!fCurrColorTableIsReal) { |
| // Nothing to draw this frame. |
| return kSuccess; |
| } |
| |
| bool frameDecoded = false; |
| const bool fatalError = !fReader->decode(frameIndex, &frameDecoded); |
| if (fatalError || !frameDecoded || fRowsDecoded != scaledHeight) { |
| if (rowsDecoded) { |
| *rowsDecoded = fRowsDecoded; |
| } |
| if (fatalError) { |
| return kErrorInInput; |
| } |
| return kIncompleteInput; |
| } |
| |
| return kSuccess; |
| } |
| |
| void SkLibGifCodec::applyXformRow(const SkImageInfo& dstInfo, void* dst, const uint8_t* src) const { |
| if (this->xformOnDecode()) { |
| SkASSERT(this->colorXform()); |
| fSwizzler->swizzle(fXformBuffer.get(), src); |
| |
| const int xformWidth = get_scaled_dimension(dstInfo.width(), fSwizzler->sampleX()); |
| this->applyColorXform(dst, fXformBuffer.get(), xformWidth); |
| } else { |
| fSwizzler->swizzle(dst, src); |
| } |
| } |
| |
| template <typename T> |
| static void blend_line(void* dstAsVoid, const void* srcAsVoid, int width) { |
| T* dst = reinterpret_cast<T*>(dstAsVoid); |
| const T* src = reinterpret_cast<const T*>(srcAsVoid); |
| while (width --> 0) { |
| if (*src != 0) { // GIF pixels are either transparent (== 0) or opaque (!= 0). |
| *dst = *src; |
| } |
| src++; |
| dst++; |
| } |
| } |
| |
| void SkLibGifCodec::haveDecodedRow(int frameIndex, const unsigned char* rowBegin, |
| int rowNumber, int 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 int width = frameContext->width(); |
| const int xBegin = frameContext->xOffset(); |
| const int yBegin = frameContext->yOffset() + rowNumber; |
| const int xEnd = std::min(xBegin + width, this->dimensions().width()); |
| const int yEnd = std::min(yBegin + repeatCount, this->dimensions().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; |
| |
| // 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 (int 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; |
| } |
| |
| 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 + repeatCount > scaledHeight) { |
| repeatCount = scaledHeight - dstRow; |
| SkASSERT(repeatCount >= 1); |
| } |
| break; |
| } |
| } |
| |
| if (!foundNecessaryRow) { |
| return; |
| } |
| } else { |
| // Make sure the repeatCount does not take us beyond the end of the dst |
| SkASSERT(this->dstInfo().height() >= yBegin); |
| repeatCount = std::min(repeatCount, 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 { |
| this->applyXformRow(dstInfo, fTmpBuffer.get(), rowBegin); |
| |
| size_t offsetBytes = fSwizzler->swizzleOffsetBytes(); |
| if (dstInfo.colorType() == kRGBA_F16_SkColorType) { |
| // Account for the fact that post-swizzling we converted to F16, |
| // which is twice as wide. |
| offsetBytes *= 2; |
| } |
| const void* src = SkTAddOffset<void>(fTmpBuffer.get(), offsetBytes); |
| void* dst = SkTAddOffset<void>(dstLine, offsetBytes); |
| |
| switch (dstInfo.colorType()) { |
| case kBGRA_8888_SkColorType: |
| case kRGBA_8888_SkColorType: |
| blend_line<uint32_t>(dst, src, fSwizzler->swizzleWidth()); |
| break; |
| case kRGBA_F16_SkColorType: |
| blend_line<uint64_t>(dst, src, fSwizzler->swizzleWidth()); |
| break; |
| default: |
| SkASSERT(false); |
| return; |
| } |
| } |
| |
| // Tell the frame to copy the row data if need be. |
| if (repeatCount > 1) { |
| const size_t bytesPerPixel = this->dstInfo().bytesPerPixel(); |
| const size_t bytesToCopy = fSwizzler->swizzleWidth() * bytesPerPixel; |
| void* copiedLine = SkTAddOffset<void>(dstLine, fSwizzler->swizzleOffsetBytes()); |
| void* dst = copiedLine; |
| for (int i = 1; i < repeatCount; i++) { |
| dst = SkTAddOffset<void>(dst, fDstRowBytes); |
| memcpy(dst, copiedLine, bytesToCopy); |
| } |
| } |
| } |