Bug 65793

Summary:

Painting of fixed background images is wrong in composited layers

Product:

WebKit

Reporter:

Abel <abiboe>

Component:

New Bugs

Assignee:

Simon Fraser (smfr) <simon.fraser>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

bdakin, commit-queue, dino, eoconnor, esprehn+autocc, glenn, jens, menard, peter.lejeck, sam, simon.fraser, thorton

Priority:

Version:

528+ (Nightly build)

Hardware:

Mac (Intel)

OS:

OS X 10.7

URL:

http://vps708.directvps.nl/webkit/

Bug Depends on:

Bug Blocks:

93136

Attachments:

Description	Flags
HTML file to recreate the bug	none
Patch	sam: review+

Description Abel 2011-08-05 15:02:35 PDT

Elements with a fixed background image behave strange when an absolute positioned element has an animated transformation on hover.

For example, the position of the background image in the div elements in the supplied changes position moves away during the animation, and returns to it's original position when the animation is finished.
 
Hover over the black square to reproduce the bug.

Comment 1 Abel 2011-08-05 15:03:59 PDT

Created attachment 103119 [details]
HTML file to recreate the bug

Comment 2 Simon Fraser (smfr) 2011-08-06 19:21:29 PDT

Yeah, fixed backgrounds and animation don't play nicely together. Making them work would be very hard (or at least slow things down horribly).

Comment 3 Abel 2011-08-07 00:25:31 PDT

(In reply to comment #2)
> Yeah, fixed backgrounds and animation don't play nicely together. Making them work would be very hard (or at least slow things down horribly).

I understand that animating elements with a fixed background is hard, but the bug also occurs when elements without a fixed background are animated. No matter where the animated element is on the page, all the containers with fixed background display strange behavior.

Comment 4 Simon Fraser (smfr) 2013-06-15 13:04:05 PDT

*** Bug 102381 has been marked as a duplicate of this bug. ***

Comment 5 Simon Fraser (smfr) 2013-06-15 13:04:16 PDT

*** Bug 110552 has been marked as a duplicate of this bug. ***

Comment 6 Simon Fraser (smfr) 2013-06-15 13:05:23 PDT

*** Bug 117659 has been marked as a duplicate of this bug. ***

Comment 7 Simon Fraser (smfr) 2013-06-15 13:19:40 PDT

Created attachment 204773 [details]
Patch

Comment 8 Sam Weinig 2013-06-15 20:44:56 PDT

Comment on attachment 204773 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=204773&action=review

> Source/WebCore/rendering/RenderBoxModelObject.cpp:1227
> +    // FIXME: transforms spec says that fixed backgrounds behave like scroll inside transforms.

Since we have a bug on this, you should add the link.

> Source/WebCore/rendering/RenderBoxModelObject.h:203
> +        { }

I prefer these on separate lines :(.

Comment 9 Simon Fraser (smfr) 2013-06-16 14:54:25 PDT

http://trac.webkit.org/changeset/151623