Well, I have written about this before: http://truongan.name.vn/?p=706
But the file 30-metric-aliases.conf is system configuration and could be overwrite when we upgrade fontconfig. It turned out there is another much easier way to do this. The /etc/fonts/local.conf is meant to contain user settings, and Arial can be replaced with match edit. My whole local.conf file is:
<?xml version="1.0"?> <!DOCTYPE fontconfig SYSTEM "fonts.dtd"> <fontconfig> <!-- Font directory list --> <dir>/usr/share/fonts</dir> <dir>/media/data/fonts</dir> <dir>~/.fonts</dir> <!-- --> <!-- Globally use embedded bitmaps in fonts like Calibri? --> <match target="font" > <edit name="embeddedbitmap" mode="assign"> <bool>false</bool> </edit> </match> <match target="pattern" > <edit name="prefer_outline" mode="assign"> <bool>true</bool> </edit> </match> <match target="font"> <edit name="antialias" mode="assign"> <bool>true</bool> </edit> </match> <!-- Make (some) monospace/coding TTF fonts render as bitmaps? --> <!-- courier new, andale mono, monaco, etc. --> <match target="pattern" > <edit name="bitmap_monospace" mode="assign"> <bool>false</bool> </edit> </match> <!-- Force autohint always --> <!-- Useful for debugging and for free software purists --> <match target="font"> <edit name="force_autohint" mode="assign"> <bool>false</bool> </edit> </match> <!-- --> <match target="font"> <edit name="hinting" mode="assign"> <bool>true</bool> </edit> <match target="font"> <edit name="autohint" mode="assign"> <bool>true</bool> </edit> </match> <edit name="hintstyle" mode="assign"> <const>hintslight</const> </edit> </match> <match target="font"> <edit name="rgba" mode="assign"> <const>rgb</const> </edit> </match> <match target="font"> <test name="weight" compare="more"> <const>medium</const> </test> <edit name="autohint" mode="assign"> <bool>false</bool> </edit> </match> <match target="pattern"> <test qual="any" name="family"><string>Arial</string></test> <edit name="family" mode="assign" binding="same"><string>Droid Sans</string></edit> </match> </fontconfig>