[Fontconfig] Why do asian fonts contain greek glyphs?

[Simos Xenitellis]

Hi All,
There is a nasty situation in the current configuration on fontconfig 
that makes it really bad when displaying Greek.
For example, you get this issue when installing the latest Ubuntu Breezy 
(Dev version) and it looks like
http://bugzilla.ubuntu.com/attachment.cgi?id=3690

Why does Greek show like that? The characters are always slanted, big 
space between them, and in general they are terrible.
New distributions have FreeFonts and MgOpen that support Greek.

/etc/fonts/fonts.conf says:

<alias>
                <family>Bitstream Vera Sans</family>
                <family>Helvetica</family>
                <family>Arial</family>
                <family>Verdana</family>
                <family>Albany AMT</family>
                <family>Nimbus Sans L</family>
                <family>Luxi Sans</family>
                <family>Kochi Gothic</family>
                <family>AR PL KaitiM GB</family>
                <family>AR PL KaitiM Big5</family>
                <family>ＭＳ ゴシック</family>
                <family>Baekmuk Dotum</family>
                <family>SimSun</family>
                <family>FreeSans</family>
                <default><family>sans-serif</family></default>
</alias>

which means that fonts are searched in this order to find Greek glyphs. 
It would be nice and perfect, unfortunately

1. Kochi Gothic
2. AR PL KaitiM GB
3. Baekmuk Dotum

have Greek glyphs and they get matched, before FreeSans gets the chance. 
These Asian fonts appear to be double-spaced(?) and display Greek in a 
way that native Greek speakers are not used to; it looks terrible.

Therefore,
a. How can we instruct fontconfig (fonts.conf) to ignore any Greek 
glyphs found in those Asian fonts?
b. Is ignoring the Greek glyphs in those Asian fonts the correct path in 
solving the problem?

For more on this, please see
http://bugzilla.ubuntu.com/show_bug.cgi?id=15108

Cheers,
Simos Xenitellis