Title: [122507] trunk/Source/WebKit/qt
- Revision
- 122507
- Author
- k...@webkit.org
- Date
- 2012-07-12 14:37:30 -0700 (Thu, 12 Jul 2012)
Log Message
[Qt] Increase the drawing performance by merging dirty rects.
https://bugs.webkit.org/show_bug.cgi?id=91075
Patch by Huang Dongsung <luxte...@company100.net> on 2012-07-12
Reviewed by Noam Rosenthal.
QWebFramePrivate calls FrameView::paintContents as many as the number of dirty
rects, so it causes too many redundant render tree traversals.
I changed it to merge dirty rects and call FrameView::paintContents only once.
The algorithm to merge rects is copied from GTK.
When parallel image decoders are in use, each image is independently repainted
when decoding is finished. This creates a lot by repaint requests. So by merging
these repaint requests, I could improve rendering performance.
For example, I tested parallel image decoders on the locally mirrored Pinterest site.
QWebFramePrivate called FrameView::paintContents 165 times after parallel image
decoders decoded all the images. It took about 120ms on my six-core Intel Xeon machine.
This patch decreases painting time from 120ms to 30ms.
* Api/qwebframe.cpp:
(coalesceRectsIfPossible):
(QWebFramePrivate::renderRelativeCoords):
Modified Paths
Diff
Modified: trunk/Source/WebKit/qt/Api/qwebframe.cpp (122506 => 122507)
--- trunk/Source/WebKit/qt/Api/qwebframe.cpp 2012-07-12 21:35:34 UTC (rev 122506)
+++ trunk/Source/WebKit/qt/Api/qwebframe.cpp 2012-07-12 21:37:30 UTC (rev 122507)
@@ -356,6 +356,32 @@
}
#endif
+// This code is copied from ChromeClientGtk.cpp.
+static void coalesceRectsIfPossible(const QRect& clipRect, QVector<QRect>& rects)
+{
+ const unsigned int rectThreshold = 10;
+ const float wastedSpaceThreshold = 0.75f;
+ bool useUnionedRect = (rects.size() <= 1) || (rects.size() > rectThreshold);
+ if (!useUnionedRect) {
+ // Attempt to guess whether or not we should use the unioned rect or the individual rects.
+ // We do this by computing the percentage of "wasted space" in the union. If that wasted space
+ // is too large, then we will do individual rect painting instead.
+ float unionPixels = (clipRect.width() * clipRect.height());
+ float singlePixels = 0;
+ for (size_t i = 0; i < rects.size(); ++i)
+ singlePixels += rects[i].width() * rects[i].height();
+ float wastedSpace = 1 - (singlePixels / unionPixels);
+ if (wastedSpace <= wastedSpaceThreshold)
+ useUnionedRect = true;
+ }
+
+ if (!useUnionedRect)
+ return;
+
+ rects.clear();
+ rects.append(clipRect);
+}
+
void QWebFramePrivate::renderRelativeCoords(GraphicsContext* context, QFlags<QWebFrame::RenderLayer> layers, const QRegion& clip)
{
if (!frame->view() || !frame->contentRenderer())
@@ -371,6 +397,8 @@
view->updateLayoutAndStyleIfNeededRecursive();
if (layers & QWebFrame::ContentsLayer) {
+ QRect clipBoundingRect = clip.boundingRect();
+ coalesceRectsIfPossible(clipBoundingRect, vector);
for (int i = 0; i < vector.size(); ++i) {
const QRect& clipRect = vector.at(i);
@@ -396,7 +424,7 @@
context->restore();
}
#if USE(ACCELERATED_COMPOSITING)
- renderCompositedLayers(context, IntRect(clip.boundingRect()));
+ renderCompositedLayers(context, IntRect(clipBoundingRect));
#endif
}
renderFrameExtras(context, layers, clip);
Modified: trunk/Source/WebKit/qt/ChangeLog (122506 => 122507)
--- trunk/Source/WebKit/qt/ChangeLog 2012-07-12 21:35:34 UTC (rev 122506)
+++ trunk/Source/WebKit/qt/ChangeLog 2012-07-12 21:37:30 UTC (rev 122507)
@@ -1,3 +1,28 @@
+2012-07-12 Huang Dongsung <luxte...@company100.net>
+
+ [Qt] Increase the drawing performance by merging dirty rects.
+ https://bugs.webkit.org/show_bug.cgi?id=91075
+
+ Reviewed by Noam Rosenthal.
+
+ QWebFramePrivate calls FrameView::paintContents as many as the number of dirty
+ rects, so it causes too many redundant render tree traversals.
+ I changed it to merge dirty rects and call FrameView::paintContents only once.
+ The algorithm to merge rects is copied from GTK.
+
+ When parallel image decoders are in use, each image is independently repainted
+ when decoding is finished. This creates a lot by repaint requests. So by merging
+ these repaint requests, I could improve rendering performance.
+
+ For example, I tested parallel image decoders on the locally mirrored Pinterest site.
+ QWebFramePrivate called FrameView::paintContents 165 times after parallel image
+ decoders decoded all the images. It took about 120ms on my six-core Intel Xeon machine.
+ This patch decreases painting time from 120ms to 30ms.
+
+ * Api/qwebframe.cpp:
+ (coalesceRectsIfPossible):
+ (QWebFramePrivate::renderRelativeCoords):
+
2012-07-11 Steffen Imhof <steffen.im...@basyskom.com>
[Qt] Middle clicking a scrollbar causes text to be pasted.
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