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From: X230GV@TAMVM1.BITNET.UUCP
Newsgroups: mod.computers.laser-printers
Subject: Re: Scribe Metafont file format?
Message-ID: <8703110436.AA18290@ucbvax.Berkeley.EDU>
Date: Tue, 10-Mar-87 11:50:16 EST
Article-I.D.: ucbvax.8703110436.AA18290
Posted: Tue Mar 10 11:50:16 1987
Date-Received: Wed, 11-Mar-87 20:29:28 EST
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Approved: laser-lovers@washington.arpa

Well, Eric, your survey of font file formats was correct (as far as I can
tell), but a little incomplete.  I realize that if we listed all font file
formats in use we could clog the whole network, but you left out one important
one related to Metafont: packed files.

The packed file format was developed by Tomas Rockiki after gathering
statistics on many pixel files.  The PXL format was very wasteful of space
(by the admission of its authors), but the packed file format is extremely
space-efficient.  I don't know any exact stats, but I've observed that packed
files (also called PK files) are usually about 60% of the size of GF files
(which in turn are *much* smaller than PXL files).  Four PK utilities by
Rockiki are on the distribution tapes: GFtoPK, PKtoPX, PXtoPK, and PKtype.

One might expect that the packing and unpacking process would slow things
down, but it seems not to.  The packing algorithm is fairly simple, and
on most systems you save about as much on I/O as you lose in unpacking.
Many DVI drivers are now using PK files, and old ones are fairly simple to
convert; some code from PKtoPX can be patched directly into a WEB driver
without much difficulty.  I believe it was Rick Furuta or Pierre MacKay who
observed in a TUGboat last year that this is a good argument for writing
TeX related software in WEB.

Well, this message got long fast; I'd better fire it off before it gets
unmanageable . . .

Regards,
Glenn Vanderburg
X230GV@TAMVM1.Bitnet