shankar@bedrock.SRC.Honeywell.COM (Son of Knuth) (03/27/89)
How do you convert Mac GIF pictures to Apple II GIF pictures? One would expect the process to be trivial, but I have some Mac II GIF pictures which I transferred to an Apple IIGS using Apple File Exchange, and the pictures are not recognized by the GS. Is there a trick involved? --- Subash Shankar Honeywell Systems & Research Center voice: (612) 782 7558 US Snail: 3660 Technology Dr., Minneapolis, MN 55418 shankar@src.honeywell.com srcsip!shankar
cs4n+@andrew.cmu.edu (Charles Humphrey Silvers) (03/27/89)
GIF is GIF is GIF.... the format is computer independent. If the GS won't recognize the pictures, then either you are transferring them wrong or the pictures have been corrupted somehow. Sorry I can't be of any more help than that... -Chuck Silvers cs4n+@anddrew.cmu.edu
labc-3dc@web-3f.berkeley.edu (Andy McFadden) (03/27/89)
In article <19388@srcsip.UUCP> shankar@bedrock.UUCP (Son of Knuth) writes: >How do you convert Mac GIF pictures to Apple II GIF pictures? [munch...] > the pictures are not recognized by the GS. >Is there a trick involved? My roommate downloaded some GIFs from compuserve, and used a null modem cable to transfer them from his Toshiba laptop to my //gs and the Macintosh of the guy across the hall... no problems anywhere. Try bloading the first few bytes of the file ("BLOAD FOO.GIF, A$2000, L$10") and see if it has a GIF header (should be something like "GIF87a"). If not, scan ahead in the file (bload the first few thousand bytes) and see if you can find this header; it may be that you have some garbage at the start of the file. >Subash Shankar Honeywell Systems & Research Center -- fadden@cory.berkeley.edu (Andy McFadden) ...!ucbvax!cory!fadden labc-3dc@widow.berkeley.edu
-Rich-@cup.portal.com (Richard Sherman Payne) (03/28/89)
I have had problems viewing GIF files transferred with (I think) Red Ryder in the past. The problem is a 128 byte header file that some MAC software appends to the beginning of the GIF file, ignororing COMPUSERVE's specifications, and making a nonstandard GIF. It can be quite a problem stripping those first 128 bytes. First type the file, and compare it to a GIF file that you can view. If the GIF87a is well into the file, you may have to remove the header. I may write a BASIC program to do that, it might be slow, but simple, and easy to distribute. If you cannot remove the header, let me know, and I will write the program. Rich -Rich-@cup.portal.com
malczews@nunki.usc.edu (Frank Malczewski) (03/28/89)
In article <IY=PCuy00Xc7E3Gkds@andrew.cmu.edu> cs4n+@andrew.cmu.edu (Charles Humphrey Silvers) writes: >GIF is GIF is GIF.... the format is computer independent. If the GS won't >recognize >the pictures, then either you are transferring them wrong or the pictures have >been >corrupted somehow. > >Sorry I can't be of any more help than that... > >-Chuck Silvers >cs4n+@anddrew.cmu.edu If "GIF is GIF is GIF", why are there available so many stripper types of programs for all the other PCs that apparently strip some type of special header for the Mac GIF variant so they may be viewed on those PCs? (I also have similar GIF viewing problems, and I suspect it has to do with the fact that the other PCs do not have this special header, thereby causing the Mac to choke on GIFs produced on them.) -- Frank Malczewski
labc-3dc@e260-3f.berkeley.edu (Andy McFadden) (03/28/89)
In article <3253@nunki.usc.edu> malczews@nunki.usc.edu (Frank Malczewski) writes: >If "GIF is GIF is GIF", why are there available so many stripper types of >programs for all the other PCs that apparently strip some type of special >header for the Mac GIF variant so they may be viewed on those PCs? Some things need to be clarified here: where were the pictures produced (which program output them as GIF), and how are they being transferred. There are no "GIF variants"; that's like saying "SCSI variant" (oops, maybe not). Anyway, it's possible that some special header is being added; I'd guess 128 bytes. Try BLOADing a picture at about $2000 and see if the GIF87a header shows up at about $2080... GIF *is* GIF *is* GIF; while there might be some additional headers/footers, any change to the format of the stored image would render it non-GIFian. > -- Frank Malczewski -- fadden@cory.berkeley.edu (Andy McFadden) ...!ucbvax!cory!fadden labc-3dc@widow.berkeley.edu Just send the darn letter and let the computer figure it out.
drc@claris.com (Dennis Cohen) (03/28/89)
GIF is GIF; however, a lot of people transfer the GIF file from the Mac using what is referred to as MacBinary format. This results in a concatenation of three parts -- a header (finder information), the data fork, and the resource fork. If the file is transferred in this manner to a non-Mac system or one that is not using MacBinary, then the header needs to be stripped.
billkatt@sol.engin.umich.edu (billkatt) (03/29/89)
In article <3253@nunki.usc.edu> malczews@nunki.usc.edu (Frank Malczewski) writes: >In article <IY=PCuy00Xc7E3Gkds@andrew.cmu.edu> cs4n+@andrew.cmu.edu (Charles Humphrey Silvers) writes: >>GIF is GIF is GIF.... the format is computer independent. If the GS won't >>recognize >>the pictures, then either you are transferring them wrong or the pictures have >>been >>corrupted somehow. >> >>Sorry I can't be of any more help than that... >> >>-Chuck Silvers >>cs4n+@anddrew.cmu.edu > > >If "GIF is GIF is GIF", why are there available so many stripper types of >programs for all the other PCs that apparently strip some type of special >header for the Mac GIF variant so they may be viewed on those PCs? > >(I also have similar GIF viewing problems, and I suspect it has to do with >the fact that the other PCs do not have this special header, thereby causing >the Mac to choke on GIFs produced on them.) > > -- Frank Malczewski Those strippers take off the 128-byte MacBinary header. Mac GIFs do not have any extra info, but when uploaded to a bulletin board, they are often mistakenly uploaded in MacBinary format. They should be uploaded in binary format. -Steve Bollinger
LaserMan@cup.portal.com (Bob LaserMan Murrow) (03/30/89)
The Mac handles the original GIF format w/o problem. The real problem occures when a Mac user saves the file in MacBinary format rather than TEXT. The other problem occures when a Mac users uploads a text file GIF using MacBinary and the modem program tags on the header. Hence the programs like StipGIG to tear this 128 byte header off. On my home BBS which has a massive GIF collection I strip the files as I find them so they are useable by anyone. I have not been able to educate my users to the technical details of this as many Mac users only run the machine and really are not interested in file formats. Bob Murrow SYSOP PhoenixII and IIa in Cupertino All Mac BBS, well almost...320 megs of GIF and other format files
johng@iscuva.ISCS.COM (John Gardner) (03/31/89)
In article <16331@cup.portal.com> -Rich-@cup.portal.com (Richard Sherman Payne) writes: > >I have had problems viewing GIF files transferred with (I think) Red Ryder in >the past. The problem is a 128 byte header file that some MAC software >appends to the beginning of the GIF file, ignororing COMPUSERVE's You may be seeing the 128 byte MacBinary header that Red Ryder appended to the file. It has nothing to do with the GIF protocol at all. If you downloaded the file then Red Ryder would strip the MacBinary header and all would look well. You need to send the image of the file if your destination machine is unable to strip MacBinary. Send the file in Xmodem text mode which should just send the Macintosh's data fork without manipulation. I'm not extremely familiar with Red Ryder's Xmodem upload facility but it should have that kind of functionality. John Gardner {backbone}!uunet!iscuva!johng