Compressed Postscript bitmat format.

["P. T. Withington" <PTW%jasper.scrc.symbolics.com@RELAY.CS.NET>]

    Date: Thu, 6 Apr 89 13:47 EDT
    From: Stever@YUKON.SCRC.Symbolics.COM (Stephen Robbins)

	Date: Wed, 5 Apr 89 15:25 PDT
	From: DE@PHOENIX.SCH.Symbolics.COM (Doug Evans)

	    Date: Wed, 5 Apr 89 09:54:29 PDT
	    From: felix@Warbucks.AI.SRI.COM (Francois Felix INGRAND)


	    I am writing a report and I am including some hardcopies of the Lisp
	    Machine screen (Postscript format) in it. To avoid any cutting/pasting,
	    I include the "postscript file" in my document (using the \special
	    command with LaTeX/dvips).

	    Unfortunately, each screen dump is approximately 220 K...
	    Considering that I will have 60 screen dumps... It makes 12 Mega of
	    pictures for this report... (that I have to keep under postscript
	    format for inclusion)

	    I had a quick look to the format used in this screen dump, and it
	    looks like it is not compressed at all. When I run it thru "compress"
	    I get a 91.08% compression rate (after all, these screens are almost white).

	    I was just wondering if anybody have already written, in lisp for the
	    Lisp Machine side, and in postscript for the printer side, a small
	    "compressor".

	    Thanks in advance,

	    Felix

	If anyone has such a compression scheme for PostScript that can be run
	in a Lispm and decoded by a LaserWriter, I personally (and probably
	Symbolics in general) would **REALLY** be interested in seeing it.  I
	have several of my own bitmap programs that would benefit from such a
	program.

    From my days at Bachman Information Systems, I seem to recall Palladian
    Software had such a hack.  Are there any ex-Palladians on the list who
    can confirm/deny this?

    - Stephen

They had some code that did run-length encoding at the LispM end and a
PostScript "program" to decode it at the printer end.  There was some
discussion about whether the speed of printing was improved; obviously
if you store the intermediate PostScript file it is more compact.  In a
former lifetime I worked with someone who concluded printing speed lost
(because the PostScript engine was swamped by the calculations
involved), but PostScript engines have come a long way since then...

I suppose this could easily be re-invented by someone who speaks RPN if
no Palladian volunteers it.