Bug 126262 - Graphics buffer issue with clip-path and fixed positioned element
Summary: Graphics buffer issue with clip-path and fixed positioned element
Status: RESOLVED FIXED
Alias: None
Product: WebKit
Classification: Unclassified
Component: CSS (show other bugs)
Version: 528+ (Nightly build)
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Simon Fraser (smfr)
URL:
Keywords: InRadar
Depends on:
Blocks: 126207
  Show dependency tree / graph
 
Reported: 2013-12-27 07:07 PST by Dirk Schulze
Modified: 2014-02-17 11:08 PST (History)
8 users (show)

See Also:

Attachments
Example (396 bytes, text/html)
2013-12-27 07:07 PST, Dirk Schulze 		no flags Details
Patch (3.75 KB, patch)
2014-02-17 11:02 PST, Simon Fraser (smfr) 		thorton: 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 Dirk Schulze 2013-12-27 07:07:58 PST 
Created attachment 220059 [details]
Example

In the attached example there is a small example where a fixed positioned element is clipped with the clip-path property. It seems like the fixed positioned element is drawn on a graphics buffer and this buffer is not cleared. This leads to artifacts on areas that are clipped away.

Reload the example multiple times to see the issue. In Safari stable the background is always black. In nightlies the background is not stable. It even happened that a video playing in another application show through.

This just happens with "position: fixed".
Comment 1 Simon Fraser (smfr) 2013-12-30 11:15:43 PST 
Hmm, we probably think it's opaque when it isn't.
Comment 2 Radar WebKit Bug Importer 2013-12-30 11:16:26 PST 
<rdar://problem/15732905>
Comment 3 Simon Fraser (smfr) 2014-02-17 11:02:48 PST 
Created attachment 224397 [details]
Patch
Comment 4 Simon Fraser (smfr) 2014-02-17 11:08:29 PST 
https://trac.webkit.org/r164232