Status: Available Owner: ---- CC: [email protected] Labels: Type-Bug Pri-2 OS-All Area-BrowserBackend Mstone-5
New issue 25905 by [email protected]: Optimize page scrolling in the presence of animating regions http://code.google.com/p/chromium/issues/detail?id=25905 Optimize page scrolling in the presence of animating regions When instructed by WebKit to scroll a region of the page, we queue up a request to scroll soon (via PostTask). If we receive an overlapping invalidation before the scroll task runs, then the scroll rect will be unioned with the invalidation rect to result in a larger invalidation rect. This effectively disables optimized (memmove-based) scrolling, and can seriously degrade scrolling performance on many pages. (The same kind of thing happens when we paint. We have a queued up paint, and if a scroll happens during that time, we will again union the existing paint with the new scroll, thus resulting in suboptimal scrolling.) This is mostly a problem for pages with small animations like windowless flash ads and animating gifs. But, it may also explain part of the performance problems observed when scrolling a page containing a html5 video. For small invalidations relative to the scroll rect, it would probably be good to preserve the scroll and then do a deferred paint after the scroll to account for invalidation. Or, if a paint rect was already present, then we should do that paint, and then scroll separately. It should be much faster than doing a full repaint to scroll the page. Marking this Available for M5 since I think we can ship M4 without this. -- You received this message because you are listed in the owner or CC fields of this issue, or because you starred this issue. You may adjust your issue notification preferences at: http://code.google.com/hosting/settings --~--~---------~--~----~------------~-------~--~----~ Automated mail from issue updates at http://crbug.com/ Subscription options: http://groups.google.com/group/chromium-bugs -~----------~----~----~----~------~----~------~--~---
