%%% This file describes the original issue of dvi2ps.  It has undergone
%%% many changes since then.  It may be worth noting that the original
%%% version of dvi2ps was built on the foundations of a previewer
%%% program, dvibit. for the BBN BitGraph.

Dvi2ps is program the translates DVI files to PostScript (PostScript
is a trademark of Adobe Systems, Inc).  When the output of dvi2ps is
preceded by about 2 pages of PostScript code, TeX output can be
printed on PostScript devices (such as an Apple LaserWriter).

It uses the TeX-compatible set of 300 dpi fonts, and downloads the
bitmap description of each character, once, as it is needed, for every
job (i.e., resident fonts are not used).  While this sounds expensive,
it is not too bad.  After the conversion to PostScript is done, and
considering "normal documents" and 9600 baud communication, the first
page can take a minute or so to transmit and print.  Thereafter, pages
are usually printed faster.  Simple documents of 20 & 30 pages have
printed at an overall average of 3.2 pages/minute (it is unlikely that
you will ever get substantially higher than this with the program as
it currently stands).  More typical rates will be 2.5 pages/min.
Conversion time is extra, of course, but does not seem to be
excessive.

Dvi2ps currently runs on Apollo (AEGIS) and Vax 4.2BSD machines (and
shortly Macintosh XL with MacWorks).

There are many problems:

  1. It is not very clever about which fonts and characters to
     download on a per-job basis, except that each character is sent only
     once, just before it is needed.  All character and fonts are then made
     resident on the printer until the end of the job.  This consumes more
     memory on the printer (at least on the Apple LaserWriter) than is
     necessary, and can limit the size of the job than can be printed.
     "Simple" 50 page documents can be printed with room to spare (I
     suspect the limit is in the range of 70-100 pages for these, but we
     haven't tried any that large yet).  On the other hand, a section out
     of the LaTeX test files (manual) that uses 30 or more different fonts,
     some of them very large, was limited to 30 pages.  Dvi2ps has -from
     and -to options to extract ranges of pages.

  2. The resulting PostScript files are very large (they can easily be
     5 times the size of the DVI file).

  3. Character positioning is not calculated in the "official" dvitype
     manner, and so there *might* be *VERY* small anomolies.  However, care
     is taken, and the result is quite acceptable (at least to many
     untrained eyes).  In fact, positioning is better than some other
     common processors.

In summary, it was quite easy to develop and will serve us well until something
better comes along.
