Bug 52714 - Scrolling in compositing mode naively repaints non-composited parts of the page
Summary: Scrolling in compositing mode naively repaints non-composited parts of the page
Status: NEW
Alias: None
Product: WebKit
Classification: Unclassified
Component: Layout and Rendering (show other bugs)
Version: 528+ (Nightly build)
Hardware: PC Windows XP
: P2 Normal
Assignee: Nobody
URL:
Keywords: InRadar, PlatformOnly
Depends on:
Blocks:
 
Reported: 2011-01-19 06:04 PST by Adam Roben (:aroben)
Modified: 2011-01-19 11:01 PST (History)
3 users (show)

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Description Adam Roben (:aroben) 2011-01-19 06:04:15 PST
The implementation of WebView::scrollBackingStore just calls m_backingLayer->setNeedsDisplayInRect(scrollViewRect), which will cause the non-composited parts of the page that intersect scrollViewRect to be repainted. This is a naive approach; it would be faster just to blit the contents into their new location and repaint only the newly-exposed contents.
Comment 1 Adam Roben (:aroben) 2011-01-19 06:07:48 PST
Perhaps we could take advantage of our layer-tiling code to improve this case.
Comment 2 Adam Roben (:aroben) 2011-01-19 06:08:15 PST
<rdar://problem/8884671>
Comment 3 Vangelis Kokkevis 2011-01-19 11:01:45 PST
(In reply to comment #1)
> Perhaps we could take advantage of our layer-tiling code to improve this case.

You might want to take a look at the chromium tiled root layer implementation in platform/graphics/chromium .  We recently switched over to a tiled root layer to improve scrolling performance.