Changeset 52379 in webkit

Timestamp:

Dec 18, 2009 10:40:22 PM (14 years ago)

Author:

eric@webkit.org

Message:

2009-12-18 Peter Kasting <​pkasting@google.com>

Reviewed by Simon Fraser.

Add a comment about some confusing code that otherwise would look like
it might be a bug.
​https://bugs.webkit.org/show_bug.cgi?id=32534

• rendering/RenderLayer.cpp: (WebCore::RenderLayer::updateScrollInfoAfterLayout):

Location:

trunk/WebCore

Files:

• ChangeLog (modified) (1 diff)
• rendering/RenderLayer.cpp (modified) (1 diff)

trunk/WebCore/ChangeLog

@@ +1 @@
+2009-12-18  Peter Kasting  <pkasting@google.com>
+
+        Reviewed by Simon Fraser.
+
+        Add a comment about some confusing code that otherwise would look like
+        it might be a bug.
+        https://bugs.webkit.org/show_bug.cgi?id=32534
+
+        * rendering/RenderLayer.cpp:
+        (WebCore::RenderLayer::updateScrollInfoAfterLayout):
+
 2009-12-18  Nikolas Zimmermann  <nzimmermann@rim.com>
 

trunk/WebCore/rendering/RenderLayer.cpp

@@ -1891 +1891 @@
         m_hBar->setSteps(cScrollbarPixelsPerLineStep, pageStep);
         m_hBar->setProportion(clientWidth, m_scrollWidth);
+        // Explicitly set the horizontal scroll value.  This ensures that when a
+        // right-to-left scrollable area's width (or content width) changes, the
+        // top right corner of the content doesn't shift with respect to the top
+        // right corner of the area. Conceptually, right-to-left areas have
+        // their origin at the top-right, but RenderLayer is top-left oriented,
+        // so this is needed to keep everything working (see how scrollXOffset()
+        // differs from scrollYOffset() to get an idea of why the horizontal and
+        // vertical scrollbars need to be treated differently).
         m_hBar->setValue(scrollXOffset());
     }