Path: utzoo!utgpu!watserv1!watmath!att!linac!pacific.mps.ohio-state.edu!zaphod.mps.ohio-state.edu!think.com!mintaka!bloom-beacon!SABER.COM!jimf
From: jimf@SABER.COM
Newsgroups: comp.windows.x
Subject: Re: Displaying GIF pictures under X windows
Message-ID: <9011291527.AA29733@test4>
Date: 29 Nov 90 15:27:18 GMT
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 19

|From reading the compuserv GIF documentation, I was under the impression
|the GIF standard was meant to be easily extensible. Software written for
|old versions of the standard would just ignore blocks that they didn't
|understand. If this is so, they WHY do so many programmers who write
|GIF readers insist on checking for "GIF87a" in the header? This seems
|incredibly short sighted to me.
|
|If there is a good reason for this, I would like to hear it.

Xloadimage, for one, reads not only GIF files but twelve other
graphics formats.  It's often difficult to distinguish between formats
quickly, and in some cases it's nearly impossible -- especially when
some formats are derived from others.  When an image format supplies a
magic number of some sort, there's a strong tendency to look at that
magic number to determine if you should bother going further.

jim frost
saber software
jimf@saber.com