Dvi2ps is the program to translate 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).

The current version is set to use gf format fonts at 300 dpi (gf is Generic
Font format as produced by METAFONT, and is a much tighter format than
the old loose-packed pxl format, which is now officially obsolete.)
The Makefile allows dvi2ps to be compiled for the use of pxl files, but
we strongly advise conversion to gf format. dvi2ps 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 
better speeds 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.  There is no effective way of converting
carefully rasterised fonts as produced by METAFONT into PostScript outlines,
but some thought is being given to rewriting the output end of METAFONT
to produce PostScript.

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.

-------> N.B. 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 are small anomalies.  However, care is taken,
     and the result is quite acceptable (at least to many untrained eyes).

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

(This file last updated 8 September, 1986, by P. A. MacKay)
