Avoid spurious "all repaint" layouts when scrolling WebViews on Retina displays
https://bugs.webkit.org/show_bug.cgi?id=119564
Reviewed by Beth Dakin.
When scrolling WebViews on Macs with Retina displays, AppKit uses
device pixels for the scroll offset, so [scrollView() documentVisibleRect]
can return a CGRect with non-integral origin. This rect is used by layout,
via layoutSize(), to decide whether the view size changed, which prompts
a full repaint. However, FrameView gets a value which has been rounded
by enclosingIntRect(), which increases the height or width by 1px if the
y or x offset is on a half-pixel, causing spurious full repaints.
Fix by plumbing through platformVisibleContentSize(), which just
gets the size of the -documentVisibleRect.
* page/FrameView.cpp:
(WebCore::FrameView::layout): Don't get layoutHeight and layoutWidth
separately, since that is two calls down into platformVisibleContentSize.
* platform/ScrollView.cpp:
(WebCore::ScrollView::unscaledVisibleContentSize):
(WebCore::ScrollView::platformVisibleContentSize):
* platform/ScrollView.h:
* platform/mac/ScrollViewMac.mm:
(WebCore::ScrollView::platformVisibleContentSize):
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153810 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/Source/WebCore/platform/ScrollView.cpp b/Source/WebCore/platform/ScrollView.cpp
index 1c9125b..f1d6551 100644
--- a/Source/WebCore/platform/ScrollView.cpp
+++ b/Source/WebCore/platform/ScrollView.cpp
@@ -221,7 +221,7 @@
IntSize ScrollView::unscaledVisibleContentSize(VisibleContentRectIncludesScrollbars scrollbarInclusion) const
{
if (platformWidget())
- return platformVisibleContentRect(scrollbarInclusion == IncludeScrollbars).size();
+ return platformVisibleContentSize(scrollbarInclusion == IncludeScrollbars);
if (!m_fixedVisibleContentRect.isEmpty())
return m_fixedVisibleContentRect.size();
@@ -1412,6 +1412,11 @@
return IntRect();
}
+IntSize ScrollView::platformVisibleContentSize(bool) const
+{
+ return IntSize();
+}
+
void ScrollView::platformSetContentsSize()
{
}
