Bug 96698 - Lots of repaints in the top left tile on this site
Summary: Lots of repaints in the top left tile on this site
Status: RESOLVED FIXED
Alias: None
Product: WebKit
Classification: Unclassified
Component: Layout and Rendering (show other bugs)
Version: 528+ (Nightly build)
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Simon Fraser (smfr)
URL: http://www.telegraaf.nl/
Keywords:
Depends on:
Blocks:
 
Reported: 2012-09-13 14:53 PDT by Simon Fraser (smfr)
Modified: 2019-07-15 01:27 PDT (History)
3 users (show)

See Also:

Attachments
Patch (2.17 KB, patch)
2012-09-13 16:39 PDT, Simon Fraser (smfr) 		andersca: review+
Details | Formatted Diff | Diff
View All Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description Simon Fraser (smfr) 2012-09-13 14:53:59 PDT 
Note how, when you load http://www.telegraaf.nl/, the top left tile is continually repainting. If you scroll down you'll see a ticker on the right; deleting this ticker stops the repaints.

But why is the top left tile repainting?

TileCache::setNeedsDisplayInRect() calls:
  getTileIndexRangeForRect(intersection(enclosingIntRect(scaledRect), m_tileCoverageRect), topLeft, bottomRight);

but in some cases intersection(enclosingIntRect(scaledRect), m_tileCoverageRect) returns an empty rect. However, getTileIndexRangeForRect happily returns tile 0,0 in that case, so we dirty the top left tile anyway.
Comment 1 Simon Fraser (smfr) 2012-09-13 14:55:58 PDT 
Oh, I think the repaint will fall outside of the tile rect so this is probably a no-op. However, with repaint counters on, we dirty the repaint counter in the tile. So some cleanup would be good.
Comment 2 Simon Fraser (smfr) 2012-09-13 16:39:16 PDT 
Created attachment 163999 [details]
Patch
Comment 3 Simon Fraser (smfr) 2012-09-13 17:02:41 PDT 
http://trac.webkit.org/changeset/128529