Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!convex!rosenkra
From: rosenkra@convex.com (William Rosencranz)
Newsgroups: comp.sys.atari.st.tech
Subject: Re: GIF to SPC convertors
Message-ID: <1991Apr12.011732.8868@convex.com>
Date: 12 Apr 91 01:17:32 GMT
References: <1991Apr9.105007.10362@newcastle.ac.uk> <1991Apr9.134525.24039@informatik.uni-erlangen.de>
Sender: newsadm@convex.com (news access account)
Organization: Convex Computer Corporation, Richardson, Tx.
Lines: 32
Nntp-Posting-Host: convex1.convex.com


i posted src to mgif on c.s.a.st which includes the tricky .GIF decoding.
i end up with rgb buffers for each scan line. after that, you can do anything
u want, including recode for .SPC and dump to disk. the .spc format is
documented in the picfmt files also on atari.archive (forgot the author -
sorry). what i did was run the rgb arrays thru a floyd-steinberg ditherer
so i could view the image on monochrome (hence m(mono)gif). since i use my
sc1224 about once a year, i prefer mono gifs. as far as i know, this is
the only generally available gif viewer for which src is available. i lifted
the gif decoder from PBMplus, also on atari.archive, though no src (i used
comp.sources.unix sources). the f-s dither is my own doing. if you can get
the decoder to run faster, i'd appreciate a copy...

now that i think of it, i think the PBM package includes giftopbm and pbmtospc
converters. i have not tried these, however. with a shell that can pipe,
you should be able to do:

	giftopbm file.gif | pbmtospc >file.spc

or maybe

	cat file.gif | giftopbm | pbmtospc >file.spc

pbm format is a generic (portable) bitmap format. maybe you need ppm (pixmap)
for color images (giftoppm and ppmtospc). read the docs on PBMplus. i don't
remember which is which...

-bill
rosenkra@convex.com
--
Bill Rosenkranz            |UUCP: {uunet,texsun}!convex!c1yankee!rosenkra
Convex Computer Corp.      |ARPA: rosenkra%c1yankee@convex.com