There are two filters in this package which are based on the Roland
plotter command set.

1. DXY: A simple command set which is used with all DXY plotters

2. RD-GL: This command set is a superset of the HP (Hewlet Packard)
   graphics language.

Not all the commands of DXY or RD-GL (HPGL) are implemented (approx 95%
are) and those commands that are not are skipped and a warning given.
It is very easy to add to this filter if a particular unimplemented
command is desired.

If you wish to implement a command go to the relevant portion in the
command switch "dxycom.c" or "hpglcom.c" and call an appropriate user
written procedure.  (You will need a good knowledge of writing
PostScript programs)

The filters use the the procedure "getopt" which is used to interpret
command line options and arguments and is normally available on 4.3 bsd
and Sys V Unix. For those sites running 4.1 or 4.2 it may be available
as a local library and must be written into the Makefile.

IF YOU DONT HAVE GETOPT YOU WILL HAVE REWRITE THE CODE THAT INTERPRETS
COMMAND LINE OPTIONS AND ARGUMENTS.

NOTE 1: The method of writing text is not fully compatible with HPGL
and will be changed at a later date.

NOTE 2: The PostScript macros are written into a C procedure to allow
each filter to be a single stand alone program. These macros can easily
be incorporated into other filter programs.

I have written some test procedures for the testing of each filter they
are "test1.hpgl" for hpgl2ps and "test1.dxy" for dxy2ps.

Don McCormick.