867561 - incorect result of scale transform, scaled element sticks to window top

Status: RESOLVED INVALID

(Core :: Web Painting, defect)

Description

[Ivan]

Attachment: minimal test case

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:20.0) Gecko/20100101 Firefox/20.0
Build ID: 20130417085609

Steps to reproduce:

Minimal test case: http://jsfiddle.net/tdnLk/4/

1. Apply transform: scale(some value, around 1, but not 1) to element
2. Narrow down window till scrollbar appears
3. Scroll the window

OS: Ubuntu 13.04 x64


Actual results:

Scaled element sticks to the top of the window at the moment elements top is above window's top, as if it gains position: fixed, showing visual glitches.


Expected results:

Scaled element should stay at it's place.

Comment 1

[Timothy Nikkel (:tnikkel)]

I tried and I couldn't reproduce. So I guess the question I have is "is this still a problem on beta, aurora, or nightly?"

Comment 2

[Ivan]

It's still a problem in freshly installed nightly(23.0a1).

Comment 3

[Timothy Nikkel (:tnikkel)]

Thanks for trying that. Could you paste your about:support?

Comment 4

[Ivan]

Attachment: about:support

Comment 5

[Ivan]

Attachment: video of how it looks

In nightly bug appears in a bit different way. Here's a screencast of how it looks like on my laptop. In the first tab is how it looks in nightly in the second(on jsfiddle) is how it looks in both nightly and stable.

Comment 6

[Ivan]

I've disabled Intel SNA acceleration method and the problem is gone. SNA is enabled by default in current drivers. So the bug most probably is not related to firefox. I'm a bit incompetent in this area, what should i do next? Open bug on ubuntu's launchpad? Or maybe firefox is in some way responsible for this bug too, because i haven't seen any problems with SNA anywhere else.
Thank you for your help.

Comment 7

[Timothy Nikkel (:tnikkel)]

Yes, I think file a bug with ubuntu. I assume Firefox wasn't doing this before? You could use http://mozilla.github.io/mozregression/ to narrow the regression range down and maybe the specific change that caused this could give us information as to what exactly is going wrong.

Comment 8

[Ivan]

I was unable to find working nightly build, i've checked all the way down to 3.5 where afaik -moz-transform was introduced.

Comment 9

[Timothy Nikkel (:tnikkel)]

Sounds very much like it is a driver bug then, you should report it to whoever makes your driver. Thanks for working through those steps!

Comment 10

[Ivan]

Fixed in xf86-video-intel 2.21.7:
https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1178020