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The Fedora Fonts Special Interest Group
The Fedora Fonts Special Interest Group

Reporting, verifying and getting fixed text rendering issues

Text rendering ecosystem

Modern text rendering is a complex process that involves many components:

  • font files,
  • a font discovery and substitution library[1],
  • a font rasterizer library[2],
  • a text layouter library[3],
  • the settings the application passes to those components, sometimes taken from Xorg.

The root cause of a text rendering problem can occur in any of the components involved. Identifying the problem and getting it fixed will therefore often require interaction with the font designers and the developers of several of those software components. While not overly difficult or long, QA process on text rendering is not for fly-by bug reporters.

See also this article for additional information.


Given this complexity, the most efficient process for everyone involved is not to blindly report problems in Fedora bugzilla, but to do the following:

  1. Consult the known problems list to check if your issue has not been reported before.
  2. If that is the case, you can increase issue visibility and decrease its resolution time by:
    1. adding a polite comment in the issue tracker,
    2. putting yourself in CC,
    3. voting for the issue when it's possible.
  3. Otherwise:
    1. ask help on the SIG list or the ##fonts irc channel to identify what component is likely to cause the issue[4],
    2. report it directly in the upstream issue tracker of the affected component,
    3. notify the SIG by CC-ing the SIG bugs list in the upstream issue tracker.
    4. If you find the issue very impacting, you can add a new bug in Fedora bugzilla pointing to the upstream issue.

Known problems

Tagging problems
Problems are tagged by CC-ing the SIG bugs list when the upstream issue tracker allows it (any bugzilla) or by CC-ing a specific user (fedorafonts) otherwise.

Issue tracker Description Issues Tagging method and other comments Fedora package grouping (comps), specific Fedora code changes Problem list CC the bugs list Fontconfig, HarfBuzz, DejaVu, Freetype… Problem list Pango Problem list KDE (Konqueror…) Problem list Firefox, Thunderbird… Problem list Webkit Problem list

Fonts in Fedora
The Fonts SIG takes loving care of Fedora fonts. Please join this special interest group if you are interested in creating, improving, packaging, or just suggesting a font. Any help will be appreciated.
  1. Usually Fontconfig, but Java uses its own solution.
  2. Usually Freetype nowadays, but again Java uses its own solution.
  3. Pango for GNOME, internal Qt library for KDE, ICU for, HarfBuzz for future GNOME & QT).
  4. You can also find clueful help on the #dejavu irc channel