Changeset 103245 in webkit

Timestamp:

Dec 19, 2011 10:11:20 AM (12 years ago)

Author:

kling@webkit.org

Message:

Avoid instantiating ScrollAnimators when possible.
<​http://webkit.org/b/74830>

Reviewed by Beth Dakin.

Have RenderLayer::scrollToOffset() check if we're scrolling to the already
current offset. In that case, don't call down to scrollToOffsetWithoutAnimation(),
avoiding the instantiation of a ScrollAnimator.

This reduces memory consumption by 400 kB (on 32-bit) when viewing the full HTML5
spec on <​http://whatwg.org/c>, since we were creating a ScrollAnimator for every
single RenderLayer.

• rendering/RenderLayer.cpp:

(WebCore::RenderLayer::scrollToOffset):

Location:

trunk/Source/WebCore

Files:

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

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2011-12-19  Andreas Kling  <kling@webkit.org>
+
+        Avoid instantiating ScrollAnimators when possible.
+        <http://webkit.org/b/74830>
+
+        Reviewed by Beth Dakin.
+
+        Have RenderLayer::scrollToOffset() check if we're scrolling to the already
+        current offset. In that case, don't call down to scrollToOffsetWithoutAnimation(),
+        avoiding the instantiation of a ScrollAnimator.
+
+        This reduces memory consumption by 400 kB (on 32-bit) when viewing the full HTML5
+        spec on <http://whatwg.org/c>, since we were creating a ScrollAnimator for every
+        single RenderLayer.
+
+        * rendering/RenderLayer.cpp:
+        (WebCore::RenderLayer::scrollToOffset):
+
 2011-12-19  Chris Guan  <chris.guan@torchmobile.com.cn>
 

trunk/Source/WebCore/rendering/RenderLayer.cpp

@@ -1413 +1413 @@
         y = min(max<LayoutUnit>(y, 0), maxY);
     }
-    
-    ScrollableArea::scrollToOffsetWithoutAnimation(LayoutPoint(x, y));
+
+    LayoutPoint newScrollOffset(x, y);
+    if (newScrollOffset != LayoutPoint(scrollXOffset(), scrollYOffset()))
+        scrollToOffsetWithoutAnimation(newScrollOffset);
 }