Path: utzoo!mnetor!uunet!husc6!hao!noao!mcdsun!fishpond!fnf
From: fnf@fishpond.UUCP (Fred Fish)
Newsgroups: comp.graphics
Subject: Re: The 24-bit question.
Message-ID: <16@fishpond.UUCP>
Date: 11 Mar 88 04:05:41 GMT
References: <927@xn.LL.MIT.EDU>
Reply-To: fnf@fishpond.UUCP (Fred Fish)
Organization: occasionally
Lines: 27
Keywords: color, colormaps

In article <927@xn.LL.MIT.EDU> wjc@XN.LL.MIT.EDU (William J. Chiarchiaro) writes:
>Does anyone know of an algorithm for doing the following:
>
>	Take a digitized, color image composed of 24-bit pixels
>     (8 bits red, 8 bits green, 8 bits blue), and convert it to
>     an 8-bit-per-pixel color image along with a suitable
>     256-entry colormap (each entry has 8 bits of red, 8 of green,
>     and 8 of blue).

Many of the 256-color images for the Mac-II currently making the rounds
were generated precisely this way.  The were digitized on a Commodore
Amiga using a Digiview digitizer, and dumped into a file in 24-bit
color (1 byte each of RGB), transfered to a Mac-II, and then converted
to 256 color images using a program written by Steve Blackstock called
"quantize".  The resulting images were written in a format called GIF,
defined and promoted by Compuserve, and displayable by another program
of Steve's called "giffer".  I believe that both the quantizer and giffer
programs are available on Compuserve, and Steve can also be contacted
there.

-Fred



-- 
# Fred Fish    hao!noao!mcdsun!fishpond!fnf     (602) 921-1113
# Ye Olde Fishpond, 1346 West 10th Place, Tempe, AZ 85281  USA