[comp.sys.apple2] GIF for an apple ][c

q4kx@vax5.cit.cornell.edu (Joel Sumner) (03/17/90)

In article <12359@smoke.BRL.MIL>, gwyn@smoke.BRL.MIL (Doug Gwyn) writes:
> 
> It is, and in fact when I last tried IIGIF some time ago it worked fine
> with genuine GIF-format files.  However, some BBSes (notably those on
> Macintoshes) may download your GIF files with additional header garbage
> stuck on the front of the file; if the GIF viewer doesn't try to skip
> such leading garbage it won't think the file is in GIF format.  (A true
> GIF format file begins with the ASCII characters 'GIF87a'.)

Get a program called MACDOWN by (I think) Jason Harper.  It strips off the
header 'garbage' on Mac BBS's.  (the garbage is really the MacBinary Header)

-- 
Joel Sumner      GENIE:JOEL.SUMNER 
q4kx@cornella.ccs.cornell.edu   q4kx@cornella
q4kx@vax5.cit.cornell.edu       q4kx@crnlvax5
Never test for an error condition that you can't handle.

gentrys@ingr.com (Scott Gentry) (03/19/90)

In article <12359@smoke.BRL.MIL>, gwyn@smoke.BRL.MIL (Doug Gwyn) writes:

[Some stuff deleted]
> 
> I'm working on a GIF viewer for the IIGS, and somebody else recently
> announced he was doing something along the same lines.  There are two
> big problems with GIF viewing on an Apple II:  Many existing files
> contain more information than can fit on the Apple II display, and
> it is difficult to choose a good selection of colors for the Apple's
> limited palette.

Doug, you should look into Heckberts' Adaptive Partioning algorithm.  It's
just the ticket to reduce those nasty 256 color images to 16 colors for
GS use.  Some working source can be found in two unix packages, FBM and PBM.
I'm attempting a port of fbquant.c to the GS right now.  It's not a piece
of cake.  I've almost got it running.  I'll be happy to talk more about it
via E-Mail.  

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