When -moz-transform applied (scale, skew or rotate) which actually do some transformations, on images without alpha channel appears gray border. Tested in Firefox from version 3.5 to current trunk. Same or similar bug was in 3.5 and 3.6. From 4.0 and until 10.0 there was no such bug. See attached testcase with one of the affected versions (e.g. fx 10+).

Looks like this bug affects only systems with nvidia graphics cards. On a netbook with intel graphics it is WFM with Mozilla/5.0 (X11; Linux i686; rv:14.0) Gecko/20120401 Firefox/14.0a1.

WFM on Radeon HD6310 with Debian GNU/Linux x86-64 with a free driver with binary firmware, Firefox 12.0b3 and Nightly 20120328.

Aleksej, can you find the nightly this first broke in, if it works in Fx10 but is broken with current builds?

Found first build with this bug: Mozilla/5.0 (X11; Linux i686; rv:10.0a1) Gecko/20111027 Firefox/10.0a1

Aleksej, what's the build ID (the http:// URL) from about:buildconfig for that build? What about the last working one?

Broken build: http://hg.mozilla.org/mozilla-central/rev/4bb7c983d589 Last working: http://hg.mozilla.org/mozilla-central/rev/cc66accc8181

Bug appears with proprietary (295.33) and nouveau drivers (built from git 2012-02-10), but not with vesa driver. Video card is GeForce 9600 GT.

Bug is present under openSUSE 12.1 32 bits system, KDE 4.7.2, under nvidia Geforce 9400 GT while using nvidia driver 295.33.

Bug is not present while running openSUSE 12.1 32 bits under Virtual Box, with lxde desktop and guest additions version 4.1.4; browser version is the same as in my first test Firefox 11.

Aleksej, thanks for the regression range! The relevant checkins are: http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=cc66accc8181&tochange=4bb7c983d589 Matt, you have some ImageLayer-related changes in that range that look relevant.