| /* |
| * 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 "config.h" |
| #include "GIFImageDecoder.h" |
| #include "GIFImageReader.h" |
| |
| namespace WebCore { |
| |
| GIFImageDecoder::GIFImageDecoder(ImageSource::AlphaOption alphaOption, |
| ImageSource::GammaAndColorProfileOption gammaAndColorProfileOption) |
| : ImageDecoder(alphaOption, gammaAndColorProfileOption) |
| , m_alreadyScannedThisDataForFrameCount(true) |
| , m_repetitionCount(cAnimationLoopOnce) |
| , m_readOffset(0) |
| { |
| } |
| |
| GIFImageDecoder::~GIFImageDecoder() |
| { |
| } |
| |
| void GIFImageDecoder::setData(SharedBuffer* data, bool allDataReceived) |
| { |
| if (failed()) |
| return; |
| |
| ImageDecoder::setData(data, allDataReceived); |
| |
| // We need to rescan the frame count, as the new data may have changed it. |
| m_alreadyScannedThisDataForFrameCount = false; |
| } |
| |
| bool GIFImageDecoder::isSizeAvailable() |
| { |
| if (!ImageDecoder::isSizeAvailable()) |
| decode(0, GIFSizeQuery); |
| |
| return ImageDecoder::isSizeAvailable(); |
| } |
| |
| bool GIFImageDecoder::setSize(int width, int height) |
| { |
| if (ImageDecoder::isSizeAvailable() && size().width() == width && size().height() == height) |
| return true; |
| |
| if (!ImageDecoder::setSize(width, height)) |
| return false; |
| |
| prepareScaleDataIfNecessary(); |
| return true; |
| } |
| |
| size_t GIFImageDecoder::frameCount() |
| { |
| if (!m_alreadyScannedThisDataForFrameCount) { |
| // FIXME: Scanning all the data has O(n^2) behavior if the data were to |
| // come in really slowly. Might be interesting to try to clone our |
| // existing read session to preserve state, but for now we just crawl |
| // all the data. Note that this is no worse than what ImageIO does on |
| // Mac right now (it also crawls all the data again). |
| GIFImageReader reader(0); |
| reader.read((const unsigned char*)m_data->data(), m_data->size(), GIFFrameCountQuery, static_cast<unsigned>(-1)); |
| m_alreadyScannedThisDataForFrameCount = true; |
| m_frameBufferCache.resize(reader.images_count); |
| for (int i = 0; i < reader.images_count; ++i) |
| m_frameBufferCache[i].setPremultiplyAlpha(m_premultiplyAlpha); |
| } |
| |
| 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 two 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. |
| if (m_reader && (m_reader->loop_count != cLoopCountNotSeen)) |
| m_repetitionCount = m_reader->loop_count; |
| return m_repetitionCount; |
| } |
| |
| RGBA32Buffer* GIFImageDecoder::frameBufferAtIndex(size_t index) |
| { |
| if (index >= frameCount()) |
| return 0; |
| |
| RGBA32Buffer& frame = m_frameBufferCache[index]; |
| if (frame.status() != RGBA32Buffer::FrameComplete) |
| decode(index + 1, GIFFullQuery); |
| return &frame; |
| } |
| |
| bool GIFImageDecoder::setFailed() |
| { |
| m_reader.clear(); |
| return ImageDecoder::setFailed(); |
| } |
| |
| void GIFImageDecoder::clearFrameBufferCache(size_t clearBeforeFrame) |
| { |
| // In some cases, like if the decoder was destroyed while animating, we |
| // can be asked to clear more frames than we currently have. |
| if (m_frameBufferCache.isEmpty()) |
| return; // Nothing to do. |
| |
| // The "-1" here is tricky. It does not mean that |clearBeforeFrame| is the |
| // last frame we wish to preserve, but rather that we never want to clear |
| // the very last frame in the cache: it's empty (so clearing it is |
| // pointless), it's partial (so we don't want to clear it anyway), or the |
| // cache could be enlarged with a future setData() call and it could be |
| // needed to construct the next frame (see comments below). Callers can |
| // always use ImageSource::clear(true, ...) to completely free the memory in |
| // this case. |
| clearBeforeFrame = std::min(clearBeforeFrame, m_frameBufferCache.size() - 1); |
| const Vector<RGBA32Buffer>::iterator end(m_frameBufferCache.begin() + clearBeforeFrame); |
| |
| // We need to preserve frames such that: |
| // * We don't clear |end| |
| // * We don't clear the frame we're currently decoding |
| // * We don't clear any frame from which a future initFrameBuffer() call |
| // will copy bitmap data |
| // All other frames can be cleared. Because of the constraints on when |
| // ImageSource::clear() can be called (see ImageSource.h), we're guaranteed |
| // not to have non-empty frames after the frame we're currently decoding. |
| // So, scan backwards from |end| as follows: |
| // * If the frame is empty, we're still past any frames we care about. |
| // * If the frame is complete, but is DisposeOverwritePrevious, we'll |
| // skip over it in future initFrameBuffer() calls. We can clear it |
| // unless it's |end|, and keep scanning. For any other disposal method, |
| // stop scanning, as we've found the frame initFrameBuffer() will need |
| // next. |
| // * If the frame is partial, we're decoding it, so don't clear it; if it |
| // has a disposal method other than DisposeOverwritePrevious, stop |
| // scanning, as we'll only need this frame when decoding the next one. |
| Vector<RGBA32Buffer>::iterator i(end); |
| for (; (i != m_frameBufferCache.begin()) && ((i->status() == RGBA32Buffer::FrameEmpty) || (i->disposalMethod() == RGBA32Buffer::DisposeOverwritePrevious)); --i) { |
| if ((i->status() == RGBA32Buffer::FrameComplete) && (i != end)) |
| i->clear(); |
| } |
| |
| // Now |i| holds the last frame we need to preserve; clear prior frames. |
| for (Vector<RGBA32Buffer>::iterator j(m_frameBufferCache.begin()); j != i; ++j) { |
| ASSERT(j->status() != RGBA32Buffer::FramePartial); |
| if (j->status() != RGBA32Buffer::FrameEmpty) |
| j->clear(); |
| } |
| } |
| |
| void GIFImageDecoder::decodingHalted(unsigned bytesLeft) |
| { |
| m_readOffset = m_data->size() - bytesLeft; |
| } |
| |
| bool GIFImageDecoder::haveDecodedRow(unsigned frameIndex, unsigned char* rowBuffer, unsigned char* rowEnd, unsigned rowNumber, unsigned repeatCount, bool writeTransparentPixels) |
| { |
| const GIFFrameReader* frameReader = m_reader->frame_reader; |
| // The pixel data and coordinates supplied to us are relative to the frame's |
| // origin within the entire image size, i.e. |
| // (frameReader->x_offset, frameReader->y_offset). There is no guarantee |
| // that (rowEnd - rowBuffer) == (size().width() - frameReader->x_offset), so |
| // we must ensure we don't run off the end of either the source data or the |
| // row's X-coordinates. |
| int xBegin = upperBoundScaledX(frameReader->x_offset); |
| int yBegin = upperBoundScaledY(frameReader->y_offset + rowNumber); |
| int xEnd = lowerBoundScaledX(std::min(static_cast<int>(frameReader->x_offset + (rowEnd - rowBuffer)), size().width()) - 1, xBegin + 1) + 1; |
| int yEnd = lowerBoundScaledY(std::min(static_cast<int>(frameReader->y_offset + rowNumber + repeatCount), size().height()) - 1, yBegin + 1) + 1; |
| if (!rowBuffer || (xBegin < 0) || (yBegin < 0) || (xEnd <= xBegin) || (yEnd <= yBegin)) |
| return true; |
| |
| // Get the colormap. |
| const unsigned char* colorMap; |
| unsigned colorMapSize; |
| if (frameReader->is_local_colormap_defined) { |
| colorMap = frameReader->local_colormap; |
| colorMapSize = (unsigned)frameReader->local_colormap_size; |
| } else { |
| colorMap = m_reader->global_colormap; |
| colorMapSize = m_reader->global_colormap_size; |
| } |
| if (!colorMap) |
| return true; |
| |
| // Initialize the frame if necessary. |
| RGBA32Buffer& buffer = m_frameBufferCache[frameIndex]; |
| if ((buffer.status() == RGBA32Buffer::FrameEmpty) && !initFrameBuffer(frameIndex)) |
| return false; |
| |
| // Write one row's worth of data into the frame. |
| for (int x = xBegin; x < xEnd; ++x) { |
| const unsigned char sourceValue = *(rowBuffer + (m_scaled ? m_scaledColumns[x] : x) - frameReader->x_offset); |
| if ((!frameReader->is_transparent || (sourceValue != frameReader->tpixel)) && (sourceValue < colorMapSize)) { |
| const size_t colorIndex = static_cast<size_t>(sourceValue) * 3; |
| buffer.setRGBA(x, yBegin, colorMap[colorIndex], colorMap[colorIndex + 1], colorMap[colorIndex + 2], 255); |
| } else { |
| m_currentBufferSawAlpha = true; |
| // 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. |
| if (writeTransparentPixels) |
| buffer.setRGBA(x, yBegin, 0, 0, 0, 0); |
| } |
| } |
| |
| // Tell the frame to copy the row data if need be. |
| if (repeatCount > 1) |
| buffer.copyRowNTimes(xBegin, xEnd, yBegin, yEnd); |
| |
| return true; |
| } |
| |
| bool GIFImageDecoder::frameComplete(unsigned frameIndex, unsigned frameDuration, RGBA32Buffer::FrameDisposalMethod disposalMethod) |
| { |
| // Initialize the frame if necessary. Some GIFs insert do-nothing frames, |
| // in which case we never reach haveDecodedRow() before getting here. |
| RGBA32Buffer& buffer = m_frameBufferCache[frameIndex]; |
| if ((buffer.status() == RGBA32Buffer::FrameEmpty) && !initFrameBuffer(frameIndex)) |
| return false; // initFrameBuffer() has already called setFailed(). |
| |
| buffer.setStatus(RGBA32Buffer::FrameComplete); |
| buffer.setDuration(frameDuration); |
| buffer.setDisposalMethod(disposalMethod); |
| |
| 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.rect().contains(IntRect(IntPoint(), scaledSize()))) |
| buffer.setHasAlpha(false); |
| else if (frameIndex) { |
| // 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. |
| // |
| // First skip over prior DisposeOverwritePrevious frames (since they |
| // don't affect the start state of this frame) the same way we do in |
| // initFrameBuffer(). |
| const RGBA32Buffer* prevBuffer = &m_frameBufferCache[--frameIndex]; |
| while (frameIndex && (prevBuffer->disposalMethod() == RGBA32Buffer::DisposeOverwritePrevious)) |
| prevBuffer = &m_frameBufferCache[--frameIndex]; |
| |
| // 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() == RGBA32Buffer::DisposeOverwriteBgcolor) && !prevBuffer->hasAlpha() && buffer.rect().contains(prevBuffer->rect())) |
| buffer.setHasAlpha(false); |
| } |
| } |
| |
| return true; |
| } |
| |
| void GIFImageDecoder::gifComplete() |
| { |
| // Cache the repetition count, which is now as authoritative as it's ever |
| // going to be. |
| repetitionCount(); |
| |
| m_reader.clear(); |
| } |
| |
| void GIFImageDecoder::decode(unsigned haltAtFrame, GIFQuery query) |
| { |
| if (failed()) |
| return; |
| |
| if (!m_reader) |
| m_reader.set(new GIFImageReader(this)); |
| |
| // If we couldn't decode the image but we've received all the data, decoding |
| // has failed. |
| if (!m_reader->read((const unsigned char*)m_data->data() + m_readOffset, m_data->size() - m_readOffset, query, haltAtFrame) && isAllDataReceived()) |
| setFailed(); |
| } |
| |
| bool GIFImageDecoder::initFrameBuffer(unsigned frameIndex) |
| { |
| // Initialize the frame rect in our buffer. |
| const GIFFrameReader* frameReader = m_reader->frame_reader; |
| IntRect frameRect(frameReader->x_offset, frameReader->y_offset, frameReader->width, frameReader->height); |
| |
| // Make sure the frameRect doesn't extend outside the buffer. |
| if (frameRect.right() > size().width()) |
| frameRect.setWidth(size().width() - frameReader->x_offset); |
| if (frameRect.bottom() > size().height()) |
| frameRect.setHeight(size().height() - frameReader->y_offset); |
| |
| RGBA32Buffer* const buffer = &m_frameBufferCache[frameIndex]; |
| int left = upperBoundScaledX(frameRect.x()); |
| int right = lowerBoundScaledX(frameRect.right(), left); |
| int top = upperBoundScaledY(frameRect.y()); |
| int bottom = lowerBoundScaledY(frameRect.bottom(), top); |
| buffer->setRect(IntRect(left, top, right - left, bottom - top)); |
| |
| if (!frameIndex) { |
| // This is the first frame, so we're not relying on any previous data. |
| if (!buffer->setSize(scaledSize().width(), scaledSize().height())) |
| return setFailed(); |
| } else { |
| // The starting state for this frame depends on the previous frame's |
| // disposal method. |
| // |
| // Frames that use the DisposeOverwritePrevious method are effectively |
| // no-ops in terms of changing the starting state of a frame compared to |
| // the starting state of the previous frame, so skip over them. (If the |
| // first frame specifies this method, it will get treated like |
| // DisposeOverwriteBgcolor below and reset to a completely empty image.) |
| const RGBA32Buffer* prevBuffer = &m_frameBufferCache[--frameIndex]; |
| RGBA32Buffer::FrameDisposalMethod prevMethod = prevBuffer->disposalMethod(); |
| while (frameIndex && (prevMethod == RGBA32Buffer::DisposeOverwritePrevious)) { |
| prevBuffer = &m_frameBufferCache[--frameIndex]; |
| prevMethod = prevBuffer->disposalMethod(); |
| } |
| ASSERT(prevBuffer->status() == RGBA32Buffer::FrameComplete); |
| |
| if ((prevMethod == RGBA32Buffer::DisposeNotSpecified) || (prevMethod == RGBA32Buffer::DisposeKeep)) { |
| // Preserve the last frame as the starting state for this frame. |
| if (!buffer->copyBitmapData(*prevBuffer)) |
| return setFailed(); |
| } else { |
| // We want to clear the previous frame to transparent, without |
| // affecting pixels in the image outside of the frame. |
| const IntRect& prevRect = prevBuffer->rect(); |
| const IntSize& bufferSize = scaledSize(); |
| if (!frameIndex || prevRect.contains(IntRect(IntPoint(), scaledSize()))) { |
| // Clearing the first frame, or a frame the size of the whole |
| // image, results in a completely empty image. |
| if (!buffer->setSize(bufferSize.width(), bufferSize.height())) |
| return setFailed(); |
| } else { |
| // Copy the whole previous buffer, then clear just its frame. |
| if (!buffer->copyBitmapData(*prevBuffer)) |
| return setFailed(); |
| for (int y = prevRect.y(); y < prevRect.bottom(); ++y) { |
| for (int x = prevRect.x(); x < prevRect.right(); ++x) |
| buffer->setRGBA(x, y, 0, 0, 0, 0); |
| } |
| if ((prevRect.width() > 0) && (prevRect.height() > 0)) |
| buffer->setHasAlpha(true); |
| } |
| } |
| } |
| |
| // Update our status to be partially complete. |
| buffer->setStatus(RGBA32Buffer::FramePartial); |
| |
| // Reset the alpha pixel tracker for this frame. |
| m_currentBufferSawAlpha = false; |
| return true; |
| } |
| |
| } // namespace WebCore |
