Xref: utzoo comp.graphics:16214 alt.graphics.pixutils:757
Path: utzoo!utgpu!cs.utexas.edu!wuarchive!sdd.hp.com!spool.mu.edu!snorkelwacker.mit.edu!bloom-beacon!eru!hagbard!sunic!liuida!isy!lysator.liu.se!zap
From: zap@lysator.liu.se (Zap Andersson)
Newsgroups: comp.graphics,alt.graphics.pixutils
Subject: Re: Image file format poll results
Message-ID: <513@lysator.liu.se>
Date: 26 Feb 91 09:51:44 GMT
References: <1991Feb12.120203@Unify.com>
Sender: news@isy.liu.se (Lord of the News)
Organization: Lysator Computer Club, Linkoping University, Sweden
Lines: 45

G'day.

The file format polling had (a lot) incorrect entries, and I will adress
one subject: Amiga (Electronic arts) IFF here.

IFF stands for Interchange File Format and is NOT (and will never be) an
image file format per se. IFF is really just a way to structure data, in
FORM's and LIST's and PROP's and all that things (like a C struct).
 
IFF dictates the structure of a file. Then certain TYPES of IFF files exist,
such as ILBM (ILBM is an IFF FORM). This can be found in the beginning of an
Amiga picture: FORM ILBM it says! (Advanced, eh?)

ILBM stands for InterLeaved Bit Map, and is an image file format supporting 
colormapped images. The format does not really dictate a bit count limit, but
it is probably in practice only up to 8 bits.

ILBM does compressin, simple run-length encoding.

Since the IFF format can include data sets (chunks) that are application-
specific by giving a four-letter word ;-) as cunk name, and the length of
the chunk (so readers that doesn't know this chunk can skip it) it can
really contain ANY data along with the picture, gamma correction, name of
author, or shoe number of authors wives lovers daughters cat's former owner.
 
IFF is defined by Electronic Arts. If you count the 'poll' list and count
together all different mentions of IFF it comes very high on the list, above
Targa, even. 

So I wonder, why is the computer industry so keen on reinventing the wheel
over and over? The IFF format is an EXCELLENT structure for files, not only
images (There are IFF's for formatted text, 8SVX (8 bit sampled sound) and
SMUS for Simple Musical Score!!) And the ILBM format is really simple and
somewhat effective (It does compress, but the code to dompress and de-compres
is really simple). Why don't we all use IFF? Could any one person answer me
that?


Just some thoughts, really...

--
* * * * * * * * * * * * * * * * *          (This rent for space)
* My signature is smaller than  * Be warned! The letter 'Z' is Copyright 1991
* yours!  - zap@lysator.liu.se  * by Zap Inc. So are the colors Red, Green and
* * * * * * * * * * * * * * * * * Greenish-yellow (Blue was taken by IBM) 


Brought to you by Super Global Mega Corp .com