Path: utzoo!utgpu!water!watmath!clyde!bellcore!decvax!decwrl!sun!pepper!cmcmanis
From: cmcmanis%pepper@Sun.COM (Chuck McManis)
Newsgroups: comp.sys.amiga.tech
Subject: Re: 32 shades of gray
Keywords: gray scale
Message-ID: <44635@sun.uucp>
Date: 8 Mar 88 19:46:34 GMT
References: <2801@gryphon.CTS.COM>
Sender: news@sun.uucp
Reply-To: cmcmanis@sun.UUCP (Chuck McManis)
Organization: Sun Microsystems, Mountain View
Lines: 27

In article <2801@gryphon.CTS.COM> (Richard Sexton) writes:
> I've been using this tip to acheive what looks for all the world
> like 32 gray scales.
> Now, to get the additional 16 shades of gray, dither 1:1 between
> every n'th color and it's n+1'th counterpart. Use the following pattern:

I like it, but like you said, trying to get the gist of the pattern
was a bit tough. Do you do region dithering or pixel dithering?

Pixel dithering is using pixels that are actually 2 X 2 blocks of the
form 
	+-----+-----+
	|  n  | n+1 |
	+-----+-----+
	| n+1 |  n  |
	+-----+-----+
	
And 'region' dithering simply applys a pattern fill of the above pattern
to "regions" of a given grey scale. 

In the pixel techinique you get a effective 320 X 200 X 5 greyscale image
in a 640 X 400 screen. Sounds like a mode I should ad to my image processing
stuff.

--Chuck McManis
uucp: {anywhere}!sun!cmcmanis   BIX: cmcmanis  ARPAnet: cmcmanis@sun.com
These opinions are my own and no one elses, but you knew that didn't you.