X-Symbol on Mac OS X, natively

There are at least two nice native ports of GNU Emacs for Mac OS X: Aqua Emacs and Carbon Emacs.

These work well with Proof General except for the lack of support for X-Symbol. The problem is that X-Symbol contains some custom fonts which were built for the X font server machinery, in bdf format. These fonts contain mathematical symbols, derived from TeX fonts set at different sizes and at a fixed width.

It would be good if these fonts could be made available in a format understood by Mac OS X, and then in turn used inside a native Emacs port. It looks as if nobody has done this yet, so I gave it a try. Unfortunately I wasn't completely successful, but someone with a bit more determination could probably finish things off. One of the main problems is working around pecularities of font formats and encodings to get the fonts understood both by Mac OS X and by Carbon Emacs (whose font support is still in development).

There are three basic ways to go: most basic to the eventual best, which is to use Unicode fonts instead of the old X-Symbol ones. This would then also work with the xft Emacs on Linux: http://www.emacswiki.org/cgi-bin/wiki/XftGnuEmacs

Bitmap conversion: embed bdf files into a format understood by Font Book

First attempt was with ufond (part of fondu package):

= cd ProofGeneral /x-symbol/etc/fonts= = ufond -dfont xsymb0*.bdf =

This produces a file XSymb0.fam.dfont which gets silently ignored by Fontbook. It's possibly re-encoded into Mac Latin as well, but this can maybe be stopped by setting the script code:

= ufond -dfont -script 32 xsymb0*.bdf =

The file can be loaded into *fontforge* and saved again from there in different formats (also experimenting with encodings).

The aim is to get a result where Emacs recognises the font in its current hacky XFLD-emulating way:

= (x-list-fonts "-apple-xsymb0-*") =

Should return a list of fonts at the available pixel sizes and with a useful encoding. I'm not sure that the (default?) UCS encoding iso10646 is useful. The reason seems to be (I'm guessing) is that Emacs gets scared if a character set doesn't seem to contain any ASCII characters, so when making a fontset it searches for a nearby font with ASCII characters and adds them to the fontset. I managed to get further with an incantation like this:

(create-fontset-from-fontset-spec
 "-apple-xsymb0-medium-r-normal--14-*-*-*-*-*-fontset-xsymb0,
 ascii:-apple-xsymb0-medium-r-normal--14-*-*-*-*-*-iso10646-1,
latin-iso8859-1:-apple-xsymb0-medium-r-normal--14-*-*-*-*-*-iso10646-1")