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From: chris@umcp-cs.UUCP (Chris Torek)
Newsgroups: net.text
Subject: Re: DVI question
Message-ID: <1779@umcp-cs.UUCP>
Date: Tue, 11-Dec-84 13:51:26 EST
Article-I.D.: umcp-cs.1779
Posted: Tue Dec 11 13:51:26 1984
Date-Received: Thu, 13-Dec-84 02:18:47 EST
References: <256@zinfandel.UUCP> <1671@umcp-cs.UUCP> <4755@utzoo.UUCP>
Organization: U of Maryland, Computer Science Dept., College Park, MD
Lines: 33

> > TeX's output is precisely the same for every device; in fact, TeX
> > itself doesn't care *what* device will eventually be used.  ...

> I hate to tell you this, but even TeX has to care about the output
> device.  Things like character widths affect line breaks, and widths
> are seldom the same from one device to another.  The use of device-
> independent units of measurement is a red herring; the quality of the
> output is still going to be poor if the formatter has the wrong idea
> about what device the stuff is headed for.

Well, yes and no:  TeX ``likes'' a standard set of fonts (the
AM---``Almost Modern''---and hopefully soon, the CM, or Computer
Modern, fonts), which have certain properties built into them (widths,
ligatures, kerning, and so forth) and for which there are standard sets
of rasters at 200, 240, 300, and 5000 (I think) DPI.  There are rules
for positioning characters so that they will be as close as is
reasonable to the ``correct'' position (based not only on the exact
TeX-units size of the characters but also on the actual plotted
width).  With 300 DPI or better resolution, the final output is not
bad, although I'd hate to see a book printed from a base resolution
that low.

Admittedly if you are going to use an existing set of fonts that are
incompatible with the AM fonts, then the DVI file will change.
However, if (and I grant that this is a big ``if'') you have a low
resolution representation of these same fonts for use in making proof
copies, the DVI file will be precisely the same.
-- 
(This line accidently left nonblank.)

In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (301) 454-7690
UUCP:	{seismo,allegra,brl-bmd}!umcp-cs!chris
CSNet:	chris@umcp-cs		ARPA:	chris@maryland