This is because the default version of tk is 8.4, which does not support antialiased fonts. If you want, you can
aptitude install tk8.5
update-alternatives --config wish
and select wish8.5.
(8.5 is currently the default in Debian experimental <http://bugs.debian.org/515984>. Once that goes into unstable it will eventually make its way into Ubuntu.)
This is because the default version of tk is 8.4, which does not support antialiased fonts. If you want, you can alternatives --config wish
aptitude install tk8.5
update-
and select wish8.5.
(8.5 is currently the default in Debian experimental <http:// bugs.debian. org/515984>. Once that goes into unstable it will eventually make its way into Ubuntu.)