🚀 go-pugleaf

Postscript Wizards,
	I've got some code which draws pictures composed only of lines
in a mac window under mac allegro common lisp.  I wanted to be able to
edit it in a graphics program, so I wrote a few functions to dump
postscript in the format used by idraw (a macpaint clone which runs
under x and uses postscript as its save format).  A line drawn with
idraw and saved as a .ps file looks like:
	Begin %I Line
	%I b 65535
	1 0 0 [] 0 SetB
	%I cfg Black
	0 0 0 SetCFg
	%I cbg White
	1 1 1 SetCBg
	%I p
	0 SetP
	%I t
	[ 1 0 0 1 97 183 ] concat
	%I
	44 441 260 325 Line
	End
Most of the commands are defined in the idraw prolog (at the end of
this message I've included a complete idraw file for a picture
containing two lines in case you need to see this prolog to understand
the preceeding postscript), but the key line seems to be:
	44 441 260 325 Line
As far as I can tell, if I map each line in my mac window into a
paragraph like the one above except with the 4 numbers before Line
changed, everything works fine (i.e. I get a postscript file which I
can view and print).  However, the question I have is what
does the concat command do?  What do the 6 numbers mean?  Different
lines in idraw seem to have a different matrix preceeding the concat
command, but I'm not sure what those matrices do or how to generate
the correct values for them.  In some sense, since it works, maybe I
shouldn't fix it, but I'd like to make the code available to other
people and before I do that, I'd like to make sure that it's "right."
I'd appreciate any help that anyone can give me.  Also, please make
your explanations simple because I don't know anything about
postscript (in fact before yesterday when I decided I needed to dump
postscript, I'd never even seen a postscript program).

Thanks alot,
Steve

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