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From: braner@batcomputer.TN.CORNELL.EDU (braner)
Newsgroups: net.micro.atari16
Subject: Re: New way to post binaries - discussion on format
Message-ID: <1275@batcomputer.TN.CORNELL.EDU>
Date: Thu, 23-Oct-86 23:09:58 EST
Article-I.D.: batcompu.1275
Posted: Thu Oct 23 23:09:58 1986
Date-Received: Sun, 26-Oct-86 01:54:06 EST
References: <2035@dalcs.UUCP> <2844@watmath.UUCP>
Reply-To: braner@batcomputer.UUCP (braner)
Distribution: net
Organization: Theory Center, Cornell University, Ithaca NY
Lines: 23
Summary: Any ideas on efficient coding of B&W line drawings?

[]

I've been thinking recently about transferring ST screen-dumps (32K
bit-maps, one bit deep in "hires" (monochrome) mode) over the modem
(to a VAX running UNIX, to print the graphics on a laser-printer).

Since my applications are concerned with B&W line drawings which are
mostly white space, it would be very inefficient to send the whole
32K.  Also I'd like some compression method to compress it before I
ever save it on the ST disk.

I guess I could use ARC or some other standard, general purpose
compression program.  But it seems that an algorithm designed
especially for this purpose should beat general ones handily!
I am thinking about an algorithm that would compare bytes (or words)
VERTICALLY DOWN THE SCREEN, rather than along consecutive RAM.
Such an algorithm would find more runs of identical bytes.  It should
also work for color.

Is such a thing available (preferably PD)?  Is anybody working on one?
Or should I do it myself?

- Moshe Braner