Path: utzoo!attcan!uunet!ginosko!aplcen!haven!mimsy!chris
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.text
Subject: Re: TeX gf,pk,pxl files
Keywords: TeX,pk,pxl,gf,metafont
Message-ID: <19762@mimsy.UUCP>
Date: 23 Sep 89 18:55:24 GMT
References: <251AB757.452@marob.masa.com> <1989Sep23.154108.13738@cs.rochester.edu>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 24

In article <1989Sep23.154108.13738@cs.rochester.edu> ken@cs.rochester.edu
(Ken Yap) writes:
>... Gf has to be retained because MF generates that
>and also it is easy to generate. Pk is the most compact but is
>complicated to decode, but the reading routines have to be written only
>once (borrow code from MC-TeX, or the Utah drivers).

Actually, PK fonts are easier to read than GF.  The GF format has two
design botches (actually, they are tied together):

	- bounding boxes are not minimal
and	- bounding boxes are given as closed (rather than half-open)
	  intervals, but MF does not give a completely empty box as
	  [x..x-1][y..y-1] (a pair of empty closed intervals) but
	  rather as [x..x][y..y] (usually 0..0).  This box encloses
	  one point.

If bounding boxes were always minimal, the second would have to be
false (by definition); or it could be the only special case.  As it
is, font readers have to be prepared for a bounding box that allows
100x100 pixels but actually encloses 3x15 or whatnot.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris