Hi,
I have noticed that several of the non-Latin fonts we ship in Fedora contain
partial hinting information, usually not covering (or covering only very
poorly) the intended target alphabet(s) of the fonts.
In particular, several of our CJK fonts include hinting information only for
Latin characters, or otherwise covering few to no CJK ideographs.
This is a problem because the version of Freetype in Fedora 15 will see that
there is some hinting bytecode and try to use the bytecode interpreter
rather than the autohinter on the entire font. If the relevant characters
are then not actually hinted, those characters will be entirely unhinted,
looking blurry.
According to Freetype upstream, you should remove all hinting bytecode from
the fonts if it's not complete. If Freetype sees that there's no hinting
bytecode, it will now automatically fallback to the autohinter. (I got that
fixed, see
https://bugzilla.redhat.com/show_bug.cgi?id=547532 .) But the
patch doesn't help for partially hinted fonts, and Freetype upstream told me
they don't want to support these anyway (see
https://savannah.nongnu.org/patch/index.php?7471#comment9 – they say that
"auto-hinting single glyphs won't give satisfying results since the glyphs
won't blend with other, natively hinted ones").
See
https://bugzilla.redhat.com/show_bug.cgi?id=682667 for how this affects
the Indic Lohit fonts, which are now being fixed by removing the offending
hinting bytecode.
Please go through your fonts, especially non-Latin fonts, looking for
hinting bytecode, and if it isn't anywhere near complete, please remove it
from the font. (If your font is a CJK font, the hinting bytecode is very
unlikely to be anywhere near complete.) This will make your font look much
better in Fedora 15 and higher (and Fedora 13/14 with freetype-freeworld,
which was always built with the bytecode interpreter enabled and now also
includes the auto-autohint magic, as of freetype-freeworld-2.4.2-5.fc14 and
freetype-freeworld-2.3.11-6.fc13).
Thank you for your cooperation,
Kevin Kofler