Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!killer!ames!mailrus!rutgers!uwvax!oddjob!mimsy!chris
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.text
Subject: SliTeX fonts
Message-ID: <12395@mimsy.UUCP>
Date: 10 Jul 88 10:44:22 GMT
References: <330@marob.MASA.COM>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 40

In article <330@marob.MASA.COM> samperi@marob.MASA.COM (Dominick Samperi)
writes:
>I noticed one curious thing about the font ilcmss8: ... all of the
>characters in the font are blank!

All the SliTeX i* fonts are blank.  They are placeholders:

	{\red foo \blue bar}

actually translates to

(red slide)	{\visible foo \invisible bar} % not in so many \words... but
(blue slide)	{\invisible foo \visible bar} % this is the idea
(green slide)	{\invisible foo \invisible bar} % if you had green, etc.

The funny thing is that for most drivers, you have to generate
great big (well...) PXL or GF or PK files just to say, `the letter a
has no pixels, and b has no pixels, and c has no pixels, and ....'
If every letter has no pixels, why not say so?

Why not indeed?  One reason is that you still have to describe the
`bounding box' for the character.  The point of the invisible `f'
in the invisible `foo' is to take up *exactly* as much space as the
visible `f' in the visible `foo', so that when the red and blue
slides are combined, the words come out in the right places.
That bounding box information appears in each of the various font
file formats.

But wait!  That same information *also* appears in the TeX Font Metrics
(TFM) files that LaTeX itself reads.  Those files already must exist.
Why not use them?  And that is what my drivers do:

	#	TYPE	SPEC	SLOP	PATH
	font	invis	*	1	/usr/local/lib/tex/slitexfonts/%f.tfm

The `slitexfonts' directory holds links to the i*.tfm files that appear
in /usr/local/lib/tex/fonts.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris