[comp.graphics] Transferring GIFs between Mac, MS-DOS, and Unix or Sun environments.

speers@brahms.udel.edu (David Speers) (02/06/91)

Why do GIF files that work fine in a Unix environment not work in a Mac or
MS-DOS environment?  Is there a way to resolve this?

jackz@izuba.ee.lbl.gov (Jack Zelver) (02/06/91)

In article <18486@brahms.udel.edu> speers@brahms.udel.edu (David Speers) writes:
>Why do GIF files that work fine in a Unix environment not work in a Mac or
>MS-DOS environment?  Is there a way to resolve this?


Mine work just fine in all three environments.  You must have some kind of
unique problem.  There are undoubtedly several ways to resolve this.

jim@piggy.ucsb.edu (Jim Lick) (02/06/91)

In article <18486@brahms.udel.edu> speers@brahms.udel.edu (David Speers) writes:
>Why do GIF files that work fine in a Unix environment not work in a Mac or
>MS-DOS environment?  Is there a way to resolve this?

GIFs should work fine in all those environments.  I've used them and 
transferred them between all 3.  Only thing to worry about is to use
a Binary transfer protocol like Kermit or Xmodem.  And when transferring
to a Mac, make sure MacBinary is OFF.

                            Jim Lick		       
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suarez@aquarius.as.arizona.edu (Jose Suarez) (02/06/91)

In article <18486@brahms.udel.edu> speers@brahms.udel.edu (David Speers) writes:
>Why do GIF files that work fine in a Unix environment not work in a Mac or
>MS-DOS environment?  Is there a way to resolve this?

Are you sure you're transferring them to your Mac via binary mode?  I don't 
know if ALL modem file transfer protocols support binary transfers, but Kermit,
which I use, sure does.  I transfer Unix GIF files to my Mac all the time that
way.

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tom@stubby.UUCP (Tom Roehl) (02/07/91)

From article <18486@brahms.udel.edu>, by speers@brahms.udel.edu (David Speers):
> Why do GIF files that work fine in a Unix environment not work in a Mac or
> MS-DOS environment?  Is there a way to resolve this?

I have been trying to figure this out myself.   The answer I have gotten, is 
that GIF's use a CLUT or Color LookUp Table to get the colors for the picture.
I guess different machines use different CLUT's.  If anyone can confirm this,
please do.

With that in mind, does anyone out there know of utilities that can remap the
CLUT of a GIF file?  (I'm especially interested in a Mac version)

Tom
stubby!tom

kolesar@plains.NoDak.edu (Joe Kolesar) (02/08/91)

In article <18486@brahms.udel.edu> speers@brahms.udel.edu (David Speers) writes:
>Why do GIF files that work fine in a Unix environment not work in a Mac or
>MS-DOS environment?  Is there a way to resolve this?

One possible consideration for getting GIF files to work on a Mac is that
many GIF file viewers only accept a few filetypes and ignore all others.
If this is your problem, use ResEdit to edit the files to a filetype that
yours will accept.  Another possibility is that the file is corrupted in
the process of transferring.  You should also try transferring a file
back to the Unix environment to see if it still works there.  Exactly what
isn't working?  Please elaborate.

Joe

siri@otc.otca.oz (Siri Hewa) (02/15/91)

In article <18486@brahms.udel.edu> speers@brahms.udel.edu (David Speers) writes:
>Why do GIF files that work fine in a Unix environment not work in a Mac or
>MS-DOS environment?  Is there a way to resolve this?

This is not true.You may be doing something wrong.
   1. Do you uudecode first, if so
   2. Do you transfer the uudecode file to mac on BINARY . if so
   then your graphic program is at fault.
   I use photoshop or Imagefile to view.

   Siri Hewa.
   ||||OTC||
   R&D Visual Communications
   Australia.
   siri@otc.otca.oz.au