Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!sun-barr!apple!agate!linus!linus!mwunix.mitre.org!twegner From: twegner@mwunix.mitre.org (Timothy Wegner) Newsgroups: comp.graphics Subject: Re: Viewer for GIF89a Message-ID: Date: 25 Sep 90 13:30:48 GMT References: <1990Sep17.200013.10204@cbnewsh.att.com> <22187@grebyn.com> Sender: usenet@linus.mitre.org Distribution: usa Lines: 22 dlawson@grebyn.com (Drew Lawson) writes: >One factor I know is that 89a allows for 'extension records' which allow >a system to store additional information in the GIF file. I got this >from the FractInt documentation. They store the fractal computation >information in the GIF file so that you can store partially computed >fractal images. I assume that the format has other changes, but older >viewers wuold not know to ignore these records. Slight correction on the last part. The GIF87a spec specifies skipping extension blocks, so the new features should not bother older decoders. However, a few decoders (eg VPIC) refuse to decode anything without the GIF87a signature. Cshow (the older ones) beep at you, but still attempt to decode. I do not understand why the originator of this thread was unable to decode GIF89a files with an older Cshow - I have done it many times. >-- >+--------------------------------------------------------------------+ >| Is life an illusion? | Drew Lawson | >| Or does it just seem that way? | dlawson@grebyn.com | >+--------------------------------------------------------------------+