[Fontconfig] FcPattern Gotcha

Lawrence D'Oliveiro ldo at geek-central.gen.nz
Tue Nov 29 02:19:36 UTC 2016

Having found a FreeType font, Fontconfig provides the call
FcFreeTypeQueryFace, which will construct a very elaborate pattern that,
I assumed, would match exactly that font again.

However, it never seemed to work: trying to use that pattern to search
for fonts would always fail with no matches.

I figured out that the problem seems to come from the inclusion
of the “lang” and “charset” criteria in the returned pattern: the
values for these tend to consist of long lists of items separated by “|”
characters. But remove them, and the resulting pattern will correctly
find the font again.

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