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Diffstat (limited to 'third_party/gif/SkGifImageReader.cpp')
-rw-r--r--third_party/gif/SkGifImageReader.cpp160
1 files changed, 94 insertions, 66 deletions
diff --git a/third_party/gif/SkGifImageReader.cpp b/third_party/gif/SkGifImageReader.cpp
index ae5663f651..2603807cb3 100644
--- a/third_party/gif/SkGifImageReader.cpp
+++ b/third_party/gif/SkGifImageReader.cpp
@@ -312,17 +312,15 @@ sk_sp<SkColorTable> SkGIFColorMap::buildTable(SkStreamBuffer* streamBuffer, SkCo
return nullptr;
const PackColorProc proc = choose_pack_color_proc(false, colorType);
- if (m_table) {
- if (transparentPixel > (unsigned) m_table->count()
- || m_table->operator[](transparentPixel) == SK_ColorTRANSPARENT) {
- if (proc == m_packColorProc) {
- // This SkColorTable has already been built with the same transparent color and
- // packing proc. Reuse it.
- return m_table;
- }
- }
+ if (m_table && proc == m_packColorProc && m_transPixel == transparentPixel) {
+ SkASSERT(transparentPixel > (unsigned) m_table->count()
+ || m_table->operator[](transparentPixel) == SK_ColorTRANSPARENT);
+ // This SkColorTable has already been built with the same transparent color and
+ // packing proc. Reuse it.
+ return m_table;
}
m_packColorProc = proc;
+ m_transPixel = transparentPixel;
const size_t bytes = m_colors * SK_BYTES_PER_COLORMAP_ENTRY;
sk_sp<SkData> rawData(streamBuffer->getDataAtPosition(m_position, bytes));
@@ -458,7 +456,10 @@ bool SkGifImageReader::parse(SkGifImageReader::SkGIFParseQuery query)
}
case SkGIFLZWStart: {
SkASSERT(!m_frames.empty());
- m_frames.back()->setDataSize(this->getOneByte());
+ auto* currentFrame = m_frames.back().get();
+ setRequiredFrame(currentFrame);
+
+ currentFrame->setDataSize(this->getOneByte());
GETN(1, SkGIFSubBlock);
break;
}
@@ -755,33 +756,7 @@ bool SkGifImageReader::parse(SkGifImageReader::SkGIFParseQuery query)
// The three low-order bits of currentComponent[8] specify the bits per pixel.
const size_t numColors = 2 << (currentComponent[8] & 0x7);
if (currentFrameIsFirstFrame()) {
- bool hasTransparentPixel;
- if (m_frames.size() == 0) {
- // We did not see a Graphics Control Extension, so no transparent
- // pixel was specified. But if there is no color table, this frame is
- // still transparent.
- hasTransparentPixel = !isLocalColormapDefined
- && m_globalColorMap.numColors() == 0;
- } else {
- // This means we did see a Graphics Control Extension, which specifies
- // the transparent pixel
- const size_t transparentPixel = m_frames[0]->transparentPixel();
- if (isLocalColormapDefined) {
- hasTransparentPixel = transparentPixel < numColors;
- } else {
- const size_t globalColors = m_globalColorMap.numColors();
- if (!globalColors) {
- // No color table for this frame, so the frame is empty.
- // This is technically different from having a transparent
- // pixel, but we'll treat it the same - nothing to draw here.
- hasTransparentPixel = true;
- } else {
- hasTransparentPixel = transparentPixel < globalColors;
- }
- }
- }
-
- if (hasTransparentPixel) {
+ if (hasTransparentPixel(0, isLocalColormapDefined, numColors)) {
m_firstFrameHasAlpha = true;
m_firstFrameSupportsIndex8 = true;
} else {
@@ -874,44 +849,97 @@ bool SkGifImageReader::parse(SkGifImageReader::SkGIFParseQuery query)
return true;
}
+bool SkGifImageReader::hasTransparentPixel(size_t i, bool isLocalColormapDefined,
+ size_t localColors) {
+ if (m_frames.size() <= i) {
+ // This should only happen when parsing the first frame.
+ SkASSERT(0 == i);
+
+ // We did not see a Graphics Control Extension, so no transparent
+ // pixel was specified. But if there is no color table, this frame is
+ // still transparent.
+ return !isLocalColormapDefined && m_globalColorMap.numColors() == 0;
+ }
+
+ const size_t transparentPixel = m_frames[i]->transparentPixel();
+ if (isLocalColormapDefined) {
+ return transparentPixel < localColors;
+ }
+
+ const size_t globalColors = m_globalColorMap.numColors();
+ if (!globalColors) {
+ // No color table for this frame, so the frame is empty.
+ // This is technically different from having a transparent
+ // pixel, but we'll treat it the same - nothing to draw here.
+ return true;
+ }
+
+ // If there is a global color table, it will be parsed before reaching
+ // here. If its numColors is set, it will be defined.
+ SkASSERT(m_globalColorMap.isDefined());
+ return transparentPixel < globalColors;
+}
+
void SkGifImageReader::addFrameIfNecessary()
{
if (m_frames.empty() || m_frames.back()->isComplete()) {
const size_t i = m_frames.size();
std::unique_ptr<SkGIFFrameContext> frame(new SkGIFFrameContext(i));
- if (0 == i) {
- frame->setRequiredFrame(SkCodec::kNone);
- } else {
- // FIXME: We could correct these after decoding (i.e. some frames may turn out to be
- // independent although we did not determine that here).
- const SkGIFFrameContext* prevFrameContext = m_frames[i - 1].get();
- switch (prevFrameContext->getDisposalMethod()) {
- case SkCodecAnimation::Keep_DisposalMethod:
- frame->setRequiredFrame(i - 1);
- break;
- case SkCodecAnimation::RestorePrevious_DisposalMethod:
- frame->setRequiredFrame(prevFrameContext->getRequiredFrame());
- break;
- case SkCodecAnimation::RestoreBGColor_DisposalMethod:
- // If the prior frame covers the whole image
- if (prevFrameContext->frameRect() == SkIRect::MakeWH(m_screenWidth,
- m_screenHeight)
- // Or the prior frame was independent
- || prevFrameContext->getRequiredFrame() == SkCodec::kNone)
- {
- // This frame is independent, since we clear everything
- // prior frame to the BG color
- frame->setRequiredFrame(SkCodec::kNone);
- } else {
- frame->setRequiredFrame(i - 1);
- }
- break;
- }
- }
m_frames.push_back(std::move(frame));
}
}
+void SkGifImageReader::setRequiredFrame(SkGIFFrameContext* frame) {
+ const size_t i = frame->frameId();
+ if (0 == i) {
+ frame->setRequiredFrame(SkCodec::kNone);
+ return;
+ }
+
+ const SkGIFFrameContext* prevFrame = m_frames[i - 1].get();
+ if (prevFrame->getDisposalMethod() == SkCodecAnimation::RestorePrevious_DisposalMethod) {
+ frame->setRequiredFrame(prevFrame->getRequiredFrame());
+ return;
+ }
+
+ // Note: We could correct these after decoding - i.e. some frames may turn out to be
+ // independent if they do not use the transparent pixel, but that would require
+ // checking whether each pixel used the transparent pixel.
+ const SkGIFColorMap& localMap = frame->localColorMap();
+ const bool transValid = hasTransparentPixel(i, localMap.isDefined(), localMap.numColors());
+
+ const SkIRect prevFrameRect = prevFrame->frameRect();
+ const bool frameCoversPriorFrame = frame->frameRect().contains(prevFrameRect);
+
+ if (!transValid && frameCoversPriorFrame) {
+ frame->setRequiredFrame(prevFrame->getRequiredFrame());
+ return;
+ }
+
+ switch (prevFrame->getDisposalMethod()) {
+ case SkCodecAnimation::Keep_DisposalMethod:
+ frame->setRequiredFrame(i - 1);
+ break;
+ case SkCodecAnimation::RestorePrevious_DisposalMethod:
+ // This was already handled above.
+ SkASSERT(false);
+ break;
+ case SkCodecAnimation::RestoreBGColor_DisposalMethod:
+ // If the prior frame covers the whole image
+ if (prevFrameRect == SkIRect::MakeWH(m_screenWidth, m_screenHeight)
+ // Or the prior frame was independent
+ || prevFrame->getRequiredFrame() == SkCodec::kNone)
+ {
+ // This frame is independent, since we clear everything in the
+ // prior frame to the BG color
+ frame->setRequiredFrame(SkCodec::kNone);
+ } else {
+ frame->setRequiredFrame(i - 1);
+ }
+ break;
+ }
+}
+
// FIXME: Move this method to close to doLZW().
bool SkGIFLZWContext::prepareToDecode()
{
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-11 17:31:19 +0000