Checking fontconfig rules

Fontconfig has a modular design, allowing each font to contribute its own font substitution rules and workarounds, without requiring the maintenance of a large centralised static ruleset. However that also means a single package with broken rules can destabilise font priorities and make them less than awesome.

Our fontconfig rules have many origins and mistakes are common. To help identify and fix them: # yum install fontpackages-devel meld $ meld foo.conf /usr/share/fontconfig/templates/bar.conf
 * try to find a packageset that works and packageset that does not
 * compare the output of: fc-match -s :family= :lang= in both cases, with   the font family you requested and   the target locale.
 * if necessary, identify more precisely the problem font,
 * examine the fontconfig rules shipped with the problem package,
 * report your findings.

Notes: