| /* |
| * 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 "platform/image-decoders/gif/GIFImageDecoder.h" |
| |
| #include <limits> |
| #include "platform/image-decoders/gif/GIFImageReader.h" |
| #include "sky/engine/wtf/NotFound.h" |
| #include "sky/engine/wtf/PassOwnPtr.h" |
| |
| namespace blink { |
| |
| GIFImageDecoder::GIFImageDecoder(ImageSource::AlphaOption alphaOption, |
| ImageSource::GammaAndColorProfileOption gammaAndColorProfileOption, |
| size_t maxDecodedBytes) |
| : ImageDecoder(alphaOption, gammaAndColorProfileOption, maxDecodedBytes) |
| , m_repetitionCount(cAnimationLoopOnce) |
| { |
| } |
| |
| GIFImageDecoder::~GIFImageDecoder() |
| { |
| } |
| |
| void GIFImageDecoder::setData(SharedBuffer* data, bool allDataReceived) |
| { |
| if (failed()) |
| return; |
| |
| ImageDecoder::setData(data, allDataReceived); |
| if (m_reader) |
| m_reader->setData(data); |
| } |
| |
| bool GIFImageDecoder::isSizeAvailable() |
| { |
| if (!ImageDecoder::isSizeAvailable()) |
| parse(GIFSizeQuery); |
| |
| return ImageDecoder::isSizeAvailable(); |
| } |
| |
| size_t GIFImageDecoder::frameCount() |
| { |
| parse(GIFFrameCountQuery); |
| return m_frameBufferCache.size(); |
| } |
| |
| int GIFImageDecoder::repetitionCount() const |
| { |
| // This value can arrive at any point in the image data stream. Most GIFs |
| // in the wild declare it near the beginning of the file, so it usually is |
| // set by the time we've decoded the size, but (depending on the GIF and the |
| // packets sent back by the webserver) not always. If the reader hasn't |
| // seen a loop count yet, it will return cLoopCountNotSeen, in which case we |
| // should default to looping once (the initial value for |
| // |m_repetitionCount|). |
| // |
| // There are some additional wrinkles here. First, ImageSource::clear() |
| // may destroy the reader, making the result from the reader _less_ |
| // authoritative on future calls if the recreated reader hasn't seen the |
| // loop count. We don't need to special-case this because in this case the |
| // new reader will once again return cLoopCountNotSeen, and we won't |
| // overwrite the cached correct value. |
| // |
| // Second, a GIF might never set a loop count at all, in which case we |
| // should continue to treat it as a "loop once" animation. We don't need |
| // special code here either, because in this case we'll never change |
| // |m_repetitionCount| from its default value. |
| // |
| // Third, we use the same GIFImageReader for counting frames and we might |
| // see the loop count and then encounter a decoding error which happens |
| // later in the stream. It is also possible that no frames are in the |
| // stream. In these cases we should just loop once. |
| if (isAllDataReceived() && parseCompleted() && m_reader->imagesCount() == 1) |
| m_repetitionCount = cAnimationNone; |
| else if (failed() || (m_reader && (!m_reader->imagesCount()))) |
| m_repetitionCount = cAnimationLoopOnce; |
| else if (m_reader && m_reader->loopCount() != cLoopCountNotSeen) |
| m_repetitionCount = m_reader->loopCount(); |
| return m_repetitionCount; |
| } |
| |
| ImageFrame* GIFImageDecoder::frameBufferAtIndex(size_t index) |
| { |
| if (index >= frameCount()) |
| return 0; |
| |
| ImageFrame& frame = m_frameBufferCache[index]; |
| if (frame.status() != ImageFrame::FrameComplete) { |
| decode(index); |
| } |
| |
| frame.notifyBitmapIfPixelsChanged(); |
| return &frame; |
| } |
| |
| bool GIFImageDecoder::frameIsCompleteAtIndex(size_t index) const |
| { |
| return m_reader && (index < m_reader->imagesCount()) && m_reader->frameContext(index)->isComplete(); |
| } |
| |
| float GIFImageDecoder::frameDurationAtIndex(size_t index) const |
| { |
| return (m_reader && (index < m_reader->imagesCount()) && |
| m_reader->frameContext(index)->isHeaderDefined()) ? |
| m_reader->frameContext(index)->delayTime() : 0; |
| } |
| |
| bool GIFImageDecoder::setFailed() |
| { |
| m_reader.clear(); |
| return ImageDecoder::setFailed(); |
| } |
| |
| bool GIFImageDecoder::haveDecodedRow(size_t frameIndex, GIFRow::const_iterator rowBegin, size_t width, size_t rowNumber, unsigned repeatCount, bool writeTransparentPixels) |
| { |
| const GIFFrameContext* frameContext = m_reader->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 xBegin = frameContext->xOffset(); |
| const int yBegin = frameContext->yOffset() + rowNumber; |
| const int xEnd = std::min(static_cast<int>(frameContext->xOffset() + width), size().width()); |
| const int yEnd = std::min(static_cast<int>(frameContext->yOffset() + rowNumber + repeatCount), size().height()); |
| if (!width || (xBegin < 0) || (yBegin < 0) || (xEnd <= xBegin) || (yEnd <= yBegin)) |
| return true; |
| |
| const GIFColorMap::Table& colorTable = frameContext->localColorMap().isDefined() ? frameContext->localColorMap().table() : m_reader->globalColorMap().table(); |
| |
| if (colorTable.isEmpty()) |
| return true; |
| |
| GIFColorMap::Table::const_iterator colorTableIter = colorTable.begin(); |
| |
| // Initialize the frame if necessary. |
| ImageFrame& buffer = m_frameBufferCache[frameIndex]; |
| if ((buffer.status() == ImageFrame::FrameEmpty) && !initFrameBuffer(frameIndex)) |
| return false; |
| |
| const size_t transparentPixel = frameContext->transparentPixel(); |
| GIFRow::const_iterator rowEnd = rowBegin + (xEnd - xBegin); |
| ImageFrame::PixelData* currentAddress = buffer.getAddr(xBegin, yBegin); |
| |
| // We may or may not need to write transparent pixels to the buffer. |
| // If we're compositing against a previous image, it's wrong, and if |
| // we're writing atop a cleared, fully transparent buffer, it's |
| // unnecessary; 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. |
| // |
| // The loops below are almost identical. One writes a transparent pixel |
| // and one doesn't based on the value of |writeTransparentPixels|. |
| // The condition check is taken out of the loop to enhance performance. |
| // This optimization reduces decoding time by about 15% for a 3MB image. |
| if (writeTransparentPixels) { |
| for (; rowBegin != rowEnd; ++rowBegin, ++currentAddress) { |
| const size_t sourceValue = *rowBegin; |
| if ((sourceValue != transparentPixel) && (sourceValue < colorTable.size())) { |
| *currentAddress = colorTableIter[sourceValue]; |
| } else { |
| *currentAddress = 0; |
| m_currentBufferSawAlpha = true; |
| } |
| } |
| } else { |
| for (; rowBegin != rowEnd; ++rowBegin, ++currentAddress) { |
| const size_t sourceValue = *rowBegin; |
| if ((sourceValue != transparentPixel) && (sourceValue < colorTable.size())) |
| *currentAddress = colorTableIter[sourceValue]; |
| else |
| m_currentBufferSawAlpha = true; |
| } |
| } |
| |
| // Tell the frame to copy the row data if need be. |
| if (repeatCount > 1) |
| buffer.copyRowNTimes(xBegin, xEnd, yBegin, yEnd); |
| |
| buffer.setPixelsChanged(true); |
| return true; |
| } |
| |
| bool GIFImageDecoder::parseCompleted() const |
| { |
| return m_reader && m_reader->parseCompleted(); |
| } |
| |
| bool GIFImageDecoder::frameComplete(size_t frameIndex) |
| { |
| // Initialize the frame if necessary. Some GIFs insert do-nothing frames, |
| // in which case we never reach haveDecodedRow() before getting here. |
| ImageFrame& buffer = m_frameBufferCache[frameIndex]; |
| if ((buffer.status() == ImageFrame::FrameEmpty) && !initFrameBuffer(frameIndex)) |
| return false; // initFrameBuffer() has already called setFailed(). |
| |
| buffer.setStatus(ImageFrame::FrameComplete); |
| |
| if (!m_currentBufferSawAlpha) { |
| // The whole frame was non-transparent, so it's possible that the entire |
| // resulting buffer was non-transparent, and we can setHasAlpha(false). |
| if (buffer.originalFrameRect().contains(IntRect(IntPoint(), size()))) { |
| buffer.setHasAlpha(false); |
| buffer.setRequiredPreviousFrameIndex(kNotFound); |
| } else if (buffer.requiredPreviousFrameIndex() != kNotFound) { |
| // Tricky case. This frame does not have alpha only if everywhere |
| // outside its rect doesn't have alpha. To know whether this is |
| // true, we check the start state of the frame -- if it doesn't have |
| // alpha, we're safe. |
| const ImageFrame* prevBuffer = &m_frameBufferCache[buffer.requiredPreviousFrameIndex()]; |
| ASSERT(prevBuffer->disposalMethod() != ImageFrame::DisposeOverwritePrevious); |
| |
| // Now, if we're at a DisposeNotSpecified or DisposeKeep frame, then |
| // we can say we have no alpha if that frame had no alpha. But |
| // since in initFrameBuffer() we already copied that frame's alpha |
| // state into the current frame's, we need do nothing at all here. |
| // |
| // The only remaining case is a DisposeOverwriteBgcolor frame. If |
| // it had no alpha, and its rect is contained in the current frame's |
| // rect, we know the current frame has no alpha. |
| if ((prevBuffer->disposalMethod() == ImageFrame::DisposeOverwriteBgcolor) && !prevBuffer->hasAlpha() && buffer.originalFrameRect().contains(prevBuffer->originalFrameRect())) |
| buffer.setHasAlpha(false); |
| } |
| } |
| |
| return true; |
| } |
| |
| size_t GIFImageDecoder::clearCacheExceptFrame(size_t clearExceptFrame) |
| { |
| // We need to preserve frames such that: |
| // 1. We don't clear |clearExceptFrame|; |
| // 2. We don't clear any frame from which a future initFrameBuffer() call |
| // will copy bitmap data. |
| // All other frames can be cleared. |
| while ((clearExceptFrame < m_frameBufferCache.size()) && (m_frameBufferCache[clearExceptFrame].status() == ImageFrame::FrameEmpty)) |
| clearExceptFrame = m_frameBufferCache[clearExceptFrame].requiredPreviousFrameIndex(); |
| |
| return ImageDecoder::clearCacheExceptFrame(clearExceptFrame); |
| } |
| |
| void GIFImageDecoder::clearFrameBuffer(size_t frameIndex) |
| { |
| if (m_reader && m_frameBufferCache[frameIndex].status() == ImageFrame::FramePartial) { |
| // Reset the state of the partial frame in the reader so that the frame |
| // can be decoded again when requested. |
| m_reader->clearDecodeState(frameIndex); |
| } |
| ImageDecoder::clearFrameBuffer(frameIndex); |
| } |
| |
| void GIFImageDecoder::parse(GIFParseQuery query) |
| { |
| if (failed()) |
| return; |
| |
| if (!m_reader) { |
| m_reader = adoptPtr(new GIFImageReader(this)); |
| m_reader->setData(m_data); |
| } |
| |
| if (!m_reader->parse(query)) { |
| setFailed(); |
| return; |
| } |
| |
| const size_t oldSize = m_frameBufferCache.size(); |
| m_frameBufferCache.resize(m_reader->imagesCount()); |
| |
| for (size_t i = oldSize; i < m_reader->imagesCount(); ++i) { |
| ImageFrame& buffer = m_frameBufferCache[i]; |
| const GIFFrameContext* frameContext = m_reader->frameContext(i); |
| buffer.setPremultiplyAlpha(m_premultiplyAlpha); |
| buffer.setRequiredPreviousFrameIndex(findRequiredPreviousFrame(i, false)); |
| buffer.setDuration(frameContext->delayTime()); |
| buffer.setDisposalMethod(frameContext->disposalMethod()); |
| |
| // Initialize the frame rect in our buffer. |
| IntRect frameRect = frameContext->frameRect(); |
| |
| // Make sure the frameRect doesn't extend outside the buffer. |
| if (frameRect.maxX() > size().width()) |
| frameRect.setWidth(size().width() - frameRect.x()); |
| if (frameRect.maxY() > size().height()) |
| frameRect.setHeight(size().height() - frameRect.y()); |
| |
| buffer.setOriginalFrameRect(frameRect); |
| } |
| } |
| |
| void GIFImageDecoder::decode(size_t frameIndex) |
| { |
| parse(GIFFrameCountQuery); |
| |
| if (failed()) |
| return; |
| |
| Vector<size_t> framesToDecode; |
| size_t frameToDecode = frameIndex; |
| do { |
| framesToDecode.append(frameToDecode); |
| frameToDecode = m_frameBufferCache[frameToDecode].requiredPreviousFrameIndex(); |
| } while (frameToDecode != kNotFound && m_frameBufferCache[frameToDecode].status() != ImageFrame::FrameComplete); |
| |
| for (size_t i = framesToDecode.size(); i > 0; --i) { |
| size_t frameIndex = framesToDecode[i - 1]; |
| if (!m_reader->decode(frameIndex)) { |
| setFailed(); |
| return; |
| } |
| |
| // We need more data to continue decoding. |
| if (m_frameBufferCache[frameIndex].status() != ImageFrame::FrameComplete) |
| break; |
| } |
| |
| // It is also a fatal error if all data is received and we have decoded all |
| // frames available but the file is truncated. |
| if (frameIndex >= m_frameBufferCache.size() - 1 && isAllDataReceived() && m_reader && !m_reader->parseCompleted()) |
| setFailed(); |
| } |
| |
| bool GIFImageDecoder::initFrameBuffer(size_t frameIndex) |
| { |
| // Initialize the frame rect in our buffer. |
| ImageFrame* const buffer = &m_frameBufferCache[frameIndex]; |
| |
| size_t requiredPreviousFrameIndex = buffer->requiredPreviousFrameIndex(); |
| if (requiredPreviousFrameIndex == kNotFound) { |
| // This frame doesn't rely on any previous data. |
| if (!buffer->setSize(size().width(), size().height())) |
| return setFailed(); |
| } else { |
| const ImageFrame* prevBuffer = &m_frameBufferCache[requiredPreviousFrameIndex]; |
| ASSERT(prevBuffer->status() == ImageFrame::FrameComplete); |
| |
| // Preserve the last frame as the starting state for this frame. |
| if (!buffer->copyBitmapData(*prevBuffer)) |
| return setFailed(); |
| |
| if (prevBuffer->disposalMethod() == ImageFrame::DisposeOverwriteBgcolor) { |
| // We want to clear the previous frame to transparent, without |
| // affecting pixels in the image outside of the frame. |
| const IntRect& prevRect = prevBuffer->originalFrameRect(); |
| ASSERT(!prevRect.contains(IntRect(IntPoint(), size()))); |
| buffer->zeroFillFrameRect(prevRect); |
| } |
| } |
| |
| // Update our status to be partially complete. |
| buffer->setStatus(ImageFrame::FramePartial); |
| |
| // Reset the alpha pixel tracker for this frame. |
| m_currentBufferSawAlpha = false; |
| return true; |
| } |
| |
| } // namespace blink |