Bug 65793 - Painting of fixed background images is wrong in composited layers
: Painting of fixed background images is wrong in composited layers
Status: RESOLVED FIXED
: WebKit
New Bugs
: 528+ (Nightly build)
: Macintosh Intel Mac OS X 10.7
: P2 Normal
Assigned To:
: http://vps708.directvps.nl/webkit/
:
:
: 93136
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Reported: 2011-08-05 15:02 PST by
Modified: 2013-06-16 14:54 PST (History)


Attachments
HTML file to recreate the bug (653 bytes, text/html)
2011-08-05 15:03 PST, Abel
no flags Details
Patch (24.42 KB, patch)
2013-06-15 13:19 PST, Simon Fraser (smfr)
sam: review+
Review Patch | Details | Formatted Diff | Diff


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Description From 2011-08-05 15:02:35 PST
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 From 2011-08-05 15:03:59 PST -------
Created an attachment (id=103119) [details]
HTML file to recreate the bug
------- Comment #2 From 2011-08-06 19:21:29 PST -------
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 From 2011-08-07 00:25:31 PST -------
(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 From 2013-06-15 13:04:05 PST -------
*** Bug 102381 has been marked as a duplicate of this bug. ***
------- Comment #5 From 2013-06-15 13:04:16 PST -------
*** Bug 110552 has been marked as a duplicate of this bug. ***
------- Comment #6 From 2013-06-15 13:05:23 PST -------
*** Bug 117659 has been marked as a duplicate of this bug. ***
------- Comment #7 From 2013-06-15 13:19:40 PST -------
Created an attachment (id=204773) [details]
Patch
------- Comment #8 From 2013-06-15 20:44:56 PST -------
(From update of attachment 204773 [details])
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 From 2013-06-16 14:54:25 PST -------
http://trac.webkit.org/changeset/151623