Changeset 153810 in webkit

Timestamp:

Aug 7, 2013 7:00:07 PM (11 years ago)

Author:

Simon Fraser

Message:

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):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• page/FrameView.cpp (modified) (1 diff)
• platform/ScrollView.cpp (modified) (2 diffs)
• platform/ScrollView.h (modified) (1 diff)
• platform/mac/ScrollViewMac.mm (modified) (2 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2013-08-07  Simon Fraser  <simon.fraser@apple.com>
+
+        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):
+
 2013-08-07  Simon Fraser  <simon.fraser@apple.com>
 

trunk/Source/WebCore/page/FrameView.cpp

@@ -1294 +1294 @@
             LayoutSize oldSize = m_size;
 
-            m_size = LayoutSize(layoutWidth(), layoutHeight());
+            m_size = layoutSize();
 
             if (oldSize != m_size) {

trunk/Source/WebCore/platform/ScrollView.cpp

@@ -222 +222 @@
 {
     if (platformWidget())
-        return platformVisibleContentRect(scrollbarInclusion == IncludeScrollbars).size();
+        return platformVisibleContentSize(scrollbarInclusion == IncludeScrollbars);
 
     if (!m_fixedVisibleContentRect.isEmpty())
@@ -1413 +1413 @@
 }
 
+IntSize ScrollView::platformVisibleContentSize(bool) const
+{
+    return IntSize();
+}
+
 void ScrollView::platformSetContentsSize()
 {

trunk/Source/WebCore/platform/ScrollView.h

@@ -389 +389 @@
     bool platformCanBlitOnScroll() const;
     IntRect platformVisibleContentRect(bool includeScrollbars) const;
+    IntSize platformVisibleContentSize(bool includeScrollbars) const;
     void platformSetContentsSize();
     IntRect platformContentsToScreen(const IntRect&) const;

trunk/Source/WebCore/platform/mac/ScrollViewMac.mm

@@ -29 +29 @@
 #import "BlockExceptions.h"
 #import "FloatRect.h"
+#import "FloatSize.h"
 #import "IntRect.h"
 #import "Logging.h"
@@ -117 +118 @@
 }
 
+IntSize ScrollView::platformVisibleContentSize(bool includeScrollbars) const
+{
+    BEGIN_BLOCK_OBJC_EXCEPTIONS;
+    if (includeScrollbars)
+        return IntSize([scrollView() frame].size);
+
+    return expandedIntSize(FloatSize([scrollView() documentVisibleRect].size));
+    END_BLOCK_OBJC_EXCEPTIONS;
+    return IntSize();
+}
+
 void ScrollView::platformSetContentsSize()
 {