[Bug 1312500] New: Incorrect rendering (overlapping characters) of some character combinations involving diacritics(?)

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=1312500

Bug ID: 1312500
           Summary: Incorrect rendering (overlapping characters) of some
                    character combinations involving diacritics(?)
           Product: Fedora
           Version: rawhide
         Component: abattis-cantarell-fonts
          Severity: high
          Assignee: [e-mail]
          Reporter: [e-mail]
        QA Contact: [e-mail]
                CC: [e-mail], [e-mail]

So we'll need to do a bit more triage on this one, but I'm busy right now so
just want to file it. Today's openQA French install test for Rawhide failed.
The failure seems to be caused by some messed-up rendering of particular
character combinations. Here's the failed step:

https://openqa.fedoraproject.org/tests/6079/modules/_do_install_and_reboot/s...

Note the incorrect rendering of the message above the "Redémarrer" (reboot)
button, which is:

"Fedora est maintenant installé avec succès et est prêt à être utilisé !"

This text contains the two character sequence "êt" twice, and both times, it is
incorrectly rendered - the characters are overlapped.

A similar issue can be observed on the main hub:

https://openqa.fedoraproject.org/tests/6079/modules/disk_guided_empty/steps/...

with the text "NOM D'HÔTE ET RÉSEAU" - the ÔT sequence is similarly incorrectly
rendered.

As I'm writing this bug report, I've become pretty sure the bug is in
Cantarell. If I paste the text êt into gedit (where my font is DejaVu Sans
Mono) it renders fine. If I then change gedit's font to Cantarell it displays
incorrectly (overlapped, like in the screenshots). If I change to another
proportional font it also renders fine. So this seems like an error in
cantarell. It also affects â and ô and ü and Ô and a few others, but not î or
û. In gucharmap the affected characters actually display off-centre within the
boxes in the character table, so you can see which characters are affected
quite easily. Basically it seems like these characters are not correctly placed
in the glyph grid or whatever it's called - they're nearly a whole character's
width to the right of where they should be.

[Bug 1312500] Incorrect rendering (overlapping characters) of some character combinations involving diacritics(?)

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=1312500

--- Comment #1 from Adam Williamson  ---
Hmm, this is odd: the last build of abattis-cantarell-fonts was 2016-02-17, and
this test has definitely passed in openQA since then, indicating the bug wasn't
happening (I see a pass as late as 2016-02-22, and I just checked the
2016-02-22 Rawhide repo and it definitely has
abattis-cantarell-fonts-0.0.22-1.fc24.noarch.rpm, the latest build.

So *something* else must have changed between 2016-02-22 and now which somehow
affects rendering of abattis but not any other font I've checked, but I can't
see what that would be...neither freetype nor pango has changed in that time.
GTK+ 3.19.10 landed on 2016-02-24, that's the only thing I can think of that
could somehow possibly be involved?

[Bug 1312500] Incorrect rendering (overlapping characters) of some character combinations involving diacritics(?)

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=1312500

Adam Williamson  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |MODIFIED

--- Comment #2 from Adam Williamson  ---
Thanks to zaitor (Bjørn Lie):

<zaitor> adamw: that is already fixed upstream, get the new version
<zaitor>  cantarell-fonts 0.0.23 - reworked anchors for correct accent
rendering under harfbuzz 1.2.0

the fix is
https://git.gnome.org/browse/cantarell-fonts/commit/?id=434a116b0941cd794e6e...
, it seems, and cantarell 0.0.23 will fix this. I've sent 0.0.23 builds for
Rawhide and F24 now.

[Bug 1312500] Incorrect rendering (overlapping characters) of some character combinations involving diacritics(?)

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=1312500

Fedora Admin XMLRPC Client  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|[e-mail]          |[e-mail]

--- Comment #3 from Fedora Admin XMLRPC Client  ---
This package has changed ownership in the Fedora Package Database.  Reassigning
to the new owner of this component.

[Bug 1312500] Incorrect rendering (overlapping characters) of some character combinations involving diacritics(?)

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=1312500

Fabio Alessandro Locati  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |[e-mail]
              Flags|                            |needinfo?(awilliam@redhat.c
                   |                            |om)

--- Comment #4 from Fabio Alessandro Locati  ---
@Adam Williamson: This should be fixed now. Is this correct?

[Bug 1312500] Incorrect rendering (overlapping characters) of some character combinations involving diacritics(?)

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=1312500

Adam Williamson  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|MODIFIED                    |CLOSED
         Resolution|---                         |ERRATA
              Flags|needinfo?(awilliam@redhat.c |
                   |om)                         |
        Last Closed|                            |2016-05-28 10:21:32

--- Comment #5 from Adam Williamson  ---
Oh, yeah, ages ago.