[pango] Strange firefox font kerning and selected text behaviour

[Sitsofe Wheeler]

Binary package hint: firefox

Description of the problem:
On certain pages firefox seems to squash letters together so that they practically overlap creating an unusual effect. Further, selecting text makes it move around which is unexpected.

Steps to reproduce:
1. Start firefox .
2. Visit http://www.realworldtech.com/page.cfm?ArticleID=RWT082807020032&p=13 .
3. Press / and type affordable then once
4. Click once on the word affordable in the text so it becomes deselected.

Expected result:
None of the letters in the word affordable to overlap. Selection state of the word affordable not to change the spacing of words on the line.

Actual results:
"fo" letters of affordable overlap. Double clicking affordable and then deselecting shows changes spacing inbetween words (like Celeron) on the same line.

How reproducible is the problem?
The problem was reproduced on a fresh Gutsy Tribe 5 install updated to most of today's packages. Font aliasing options are at their defaults. Resolution is 86x86 dpi according to xdpyinfo. Might be related to Bug #34178 but that bug has been marked as fixed in Gutsy.

Version information:
firefox 2.0.0.6+2-0ubuntu3
libpango1.0-0 1.18.1-0ubuntu1

[Sitsofe Wheeler (sitsofe)]

Further strange kerning can be seen in the bold font of the web page http://kerneltrap.org/Linux/Tiny_Linux_Redux - the m in "From: Tim Bird <tim.bird@...>" always seems thinner than surrounding letters.

[Lee.Tambiah (flossgeek)]

I am seeing the same issue with certain words too.

[Gert Kulyk (gkulyk)]

Confirming this for Gutsy. Feisty did not have this kind of Problem for me. Especially words containing "ff" or "fl" are affected.

[Gert Kulyk (gkulyk)]

Getting Feisty-behavior when starting firefox with MOZ_DISABLE_PANGO=1. Gutsy firefox seems to no longer recognize /etc/firefox/firefoxrc and $HOME/mozilla/firefox/rc files, so putting the statement there do not change anything.

[Clayton Smith (argilo)]

I'm having this problem too in Gutsy. Feisty was working fine. In addition to "ff" and "fl", I'm also seeing problems with "fi". This is quite an annoying bug and should definitely be fixed before release.

[Clayton Smith (argilo)]

Just confirming that starting Firefox from the command line with "MOZ_DISABLE_PANGO=1 firefox &" fixes the problem, and also makes scrolling noticeably faster.

[Dzamir (dzamirro)]

Yes, with pango disabled the problem is fixed, but the fonts are not smoothed and cool as the "bugged" version.

[Antoine Büsch (antoine-busch)]

This seems to happen every time there is a ligature in a word (i.e, ff, fi, fl, etc...).

http://en.wikipedia.org/wiki/Typographical_ligature

[Lee.Tambiah (flossgeek)]

Also confirming that "MOZ_DISABLE_PANGO=1 firefox &" fixes the issue for myself

[Gert Kulyk (gkulyk)]

This report seems to me like a dupe of bug #37828 (the 11th!).

[Sitsofe Wheeler (sitsofe)]

Gert is right on the money - this is a duplicate of Bug #37828 . Marking as such.