Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(171)

Unified Diff: Source/core/platform/image-decoders/ImageDecoder.cpp

Issue 15350006: Decode GIF image frames on demand. (Closed) Base URL: https://chromium.googlesource.com/chromium/blink.git@master
Patch Set: Created 7 years, 7 months ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View side-by-side diff with in-line comments
Download patch
Index: Source/core/platform/image-decoders/ImageDecoder.cpp
diff --git a/Source/core/platform/image-decoders/ImageDecoder.cpp b/Source/core/platform/image-decoders/ImageDecoder.cpp
index b98e45a3fa8f93c9a9ccfaba21d6749ce34e02fa..09fe111a8136045c864cc48fd328314c418ac5d7 100644
--- a/Source/core/platform/image-decoders/ImageDecoder.cpp
+++ b/Source/core/platform/image-decoders/ImageDecoder.cpp
@@ -127,7 +127,7 @@ bool ImageDecoder::frameIsCompleteAtIndex(size_t index) const
unsigned ImageDecoder::frameBytesAtIndex(size_t index) const
{
- if (m_frameBufferCache.size() <= index)
+ if (m_frameBufferCache.size() <= index || m_frameBufferCache[index].status() == ImageFrame::FrameEmpty)
return 0;
// FIXME: Use the dimension of the requested frame.
return m_size.area() * sizeof(ImageFrame::PixelData);
@@ -140,4 +140,73 @@ void ImageDecoder::reportMemoryUsage(MemoryObjectInfo* memoryObjectInfo) const
info.addMember(m_frameBufferCache, "frameBufferCache");
}
+size_t ImageDecoder::clearCacheExceptFrame(size_t clearExceptFrame)
+{
+ // Don't clear if there is no or only one frame.
Peter Kasting 2013/05/29 02:02:18 Nit: "...are no frames or only one frame."
Xianzhu 2013/05/29 18:37:01 Done.
+ if (m_frameBufferCache.size() <= 1)
+ return 0;
+
Peter Kasting 2013/05/29 02:02:18 In theory, it's technically possible for ICOs to r
Xianzhu 2013/05/29 18:37:01 Done.
+ // 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;
Peter Kasting 2013/05/29 02:02:18 Nit: ; -> .
Xianzhu 2013/05/29 18:37:01 Done.
+ // All other frames can be cleared.
+ size_t frameToBeRequired = notFound;
Peter Kasting 2013/05/29 02:02:18 Nit: You can actually make this even simpler by re
Xianzhu 2013/05/29 18:37:01 Done.
+ if (clearExceptFrame < m_frameBufferCache.size() && m_frameBufferCache[clearExceptFrame].status() == ImageFrame::FrameEmpty) {
+ frameToBeRequired = clearExceptFrame;
+ do {
+ frameToBeRequired = m_frameBufferCache[frameToBeRequired].requiredPreviousFrameIndex();
+ } while (frameToBeRequired != notFound && m_frameBufferCache[frameToBeRequired].status() == ImageFrame::FrameEmpty);
+ }
+
+ size_t frameBytesCleared = 0;
+ for (size_t i = 0; i < m_frameBufferCache.size(); ++i) {
+ if (i != clearExceptFrame && i != frameToBeRequired) {
+ frameBytesCleared += frameBytesAtIndex(i);
+ clearFrameBuffer(i);
+ }
+ }
+ return frameBytesCleared;
+}
+
+void ImageDecoder::clearFrameBuffer(size_t frameIndex)
+{
+ m_frameBufferCache[frameIndex].clearPixelData();
+}
+
+size_t ImageDecoder::findRequiredPreviousFrame(size_t frameIndex)
+{
+ ASSERT(frameIndex <= m_frameBufferCache.size());
+ if (!frameIndex) {
+ // The first frame doesn't rely on any previous data.
+ return notFound;
+ }
+
+ // The starting state for this frame depends on the previous frame's
+ // disposal method.
+ size_t prevFrame = frameIndex - 1;
+ const ImageFrame* prevBuffer = &m_frameBufferCache[prevFrame];
Peter Kasting 2013/05/29 02:02:18 Here you should also ASSERT(prevBuffer->m_required
Xianzhu 2013/05/29 18:37:01 Done.
+ switch (prevBuffer->disposalMethod()) {
+ case ImageFrame::DisposeNotSpecified:
+ case ImageFrame::DisposeKeep:
+ // prevFrame will be used as the starting state for this frame.
+ // FIXME: Be even smarter by checking the frame sizes and/or alpha-containing regions.
+ return prevFrame;
+ case ImageFrame::DisposeOverwritePrevious:
+ // 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 and
+ // return the required previous frame of it.
+ return prevBuffer->requiredPreviousFrameIndex();
+ case ImageFrame::DisposeOverwriteBgcolor:
+ // If the previous frame fills the whole image, then the current frame
+ // can be decoded alone. Otherwise, prevFrame contributes to this frame.
+ // However, the first frame always clears even it partially covers.
Peter Kasting 2013/05/29 02:02:18 We can actually be even smarter here by handling c
Xianzhu 2013/05/29 18:37:01 Done. Thanks for the idea.
+ return !prevFrame || prevBuffer->originalFrameRect().contains(IntRect(IntPoint(), size())) ? notFound : prevFrame;
+ default:
+ ASSERT_NOT_REACHED();
+ return notFound;
+ }
+}
+
} // namespace WebCore

Powered by Google App Engine
This is Rietveld 408576698