Bug 85434

Summary:

Overlapping canvas gradients causes flicker.

Product:

WebKit

Reporter:

Greg Ray <greg>

Component:

Canvas

Assignee:

Nobody <webkit-unassigned>

Status:

RESOLVED CONFIGURATION CHANGED

Severity:

Major

CC:

bfulgham, simon.fraser, webkit-bug-importer

Priority:

Keywords:

InRadar

Version:

528+ (Nightly build)

Hardware:

Mac (Intel)

OS:

OS X 10.7

Attachments:

Description	Flags
Example of flicker caused by winding.	none
Flicker stops when overlapping gradient removed.	none

Greg Ray

Reported 2012-05-02 16:43:59 PDT

Created attachment 139913 [details] Example of flicker caused by winding. Please review attached file for example. I am using a technique of clockwise followed by anti clockwise to punch a hole in path and then clipping the non overlapping portions of the anti clockwise path to create a inset shadow effect. I suspect its either taking to much time to perform the draw operations or the shader buffer is overflowing. Expected no flicker. Got flicker.

Attachments
Example of flicker caused by winding. (10.42 KB, text/html) 2012-05-02 16:43 PDT, Greg Ray	no flags	Details
Flicker stops when overlapping gradient removed. (10.70 KB, text/html) 2012-05-02 17:48 PDT, Greg Ray	no flags	Details
View All Add attachment proposed patch, testcase, etc.

Greg Ray

Comment 1 2012-05-02 17:47:41 PDT

Turns out this was caused by overlapping gradients. I removed the overlapping gradient and it stopped flickering. Adding additional attachment with non-overlapping gradient for reference.

Greg Ray

Comment 2 2012-05-02 17:48:17 PDT

Created attachment 139926 [details] Flicker stops when overlapping gradient removed.

Radar WebKit Bug Importer

Comment 3 2012-05-03 13:55:09 PDT

<rdar://problem/11376226>

Simon Fraser (smfr)

Comment 4 2015-10-24 21:06:06 PDT

Does this bug still reproduce in Safari 9?

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