Path: utzoo!mnetor!motto!ecijmm!robohack!woods
From: woods@robohack.UUCP
Newsgroups: comp.text
Subject: Re: WYSIWYG flamage (was Re: what i
Summary: troff device independence and page layout control
Message-ID: <1989Aug17.232344.8058@robohack.uucp>
Date: 17 Aug 89 23:23:44 GMT
References: <210927@<1989Jul28> <77900019@p.cs.uiuc.edu>
Reply-To: woods@robohack.UUCP (Greg A. Woods)
Organization: R. H. Lathwell Associates: Elegant Communications, Inc.
Lines: 57

In article <77900019@p.cs.uiuc.edu> gillies@p.cs.uiuc.edu writes:
> 
> Answer: Well, maybe he cannot.  Are you aware that troff layout
> depends heavily on the type of output printer?  Do you realize that
> all your widow control (figure placement) depends on where the page
> breaks end up?  Troff supports at least 3 types of printers (Imagen,
> Postscript, HP Laserjet), and each kind has different character widths.

Actually, ditroff supports an infinite number of high quality printers
and typesetters, as well as an infinite number of graphics devices.
You see it is device independent, and only requires a description of
the device in order to produce output that may be directly translated
into codes for that device.

> In fact, this week I reformatted an Impress document in Postscript,
> and the output was lousy.  To share this document (original in
> Impress) with someone using a Postscript printer would result in a war
> over equation and figure placement.
>
> This is a general problem not confined to troff.  So don't assume that
> troff solves this problem -- it does not.  Nobody has solved this
> problem.

Troff solves this problem most elegantly.  With appropriate use of
displays, and user exits, troff will do its very best to make good use
of any output device specified.  All you have to do is describe the
rules you would use to place a figure or table on the page.  If this
is done sufficiently well, troff will always make the right decision.
If you need to break your own rules, provide options for the macro.

> On the other hand, using a device-independent standard like
> postscript, at least you can pass a hardcopy to a friend, and
> information will not be redistributed or mangled among the pages (ever
> see what happen to a table when it crosses a page?)

Ah, I think you've missed the point!  While PostScript may indeed be a
device independent page description language, it is not often used in
such a manner so as to be style, layout, and composition independent.
Troff, if used carefully, makes the job of being style, layout, and
composition independent much easier, while still retaining device
independence.  I don't think PostScript even contains the mechanisms
to deal with the higher level concepts of text processing, though I
suppose someone will write PostScript code to prove me wrong.  Why not
write a set of PostScript functions to emulate LaTeX?  I don't even
know it it would be possible.  If so, does that mean PostScript is
superior?  I don't think so.  Is assembler superior to C?  Is this a
good analogy?

Troff's fault is that it requires somewhat more work than most people
like to do.  Perhaps TeX with an extensible macro package would be
better.  I don't know, as I've not had the pleasure of learning to use
TeX yet.
-- 
						Greg A. Woods

woods@{robohack,gate,tmsoft,ontmoh,utgpu,gpu.utcs.Toronto.EDU,utorgpu.BITNET}
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