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From: cks@radio.toronto.edu
Newsgroups: comp.sys.amiga
Subject: Looking for general IFF floating point and coordinate point formats
Message-ID: <561@radio.toronto.edu>
Date: Wed, 4-Nov-87 21:21:58 EST
Article-I.D.: radio.561
Posted: Wed Nov  4 21:21:58 1987
Date-Received: Sun, 8-Nov-87 07:20:42 EST
Sender: cks@radio.toronto.edu
Reply-To: cks@radio.toronto.edu (Chris Siebenmann)
Organization: Newsreaders Anonymous
Lines: 40

[Reposted due to news problems; I'm sorry if you see this twice.]

 We're working on an application that needs to save floating point data
in an IFF file, and we want to make the floating point format as
general as possible. Does such a standard way of representing floating
point values in IFF files already exist? Does anyone have any ideas
about what it should be?

 Thinking about it, we've come up with a few ideas:

1)	Ascii, formated by sprintf. This has the advantage that it is
easy to decode and encode, but we'd like something more compact.

2)	ULONG value, WORD (or LONG) exponent, such that float = value
* 2**exponent. This has the advantage of being relatively compact and
easy to compute with standard C library routines, but it has problems
with large values (like doubles). Large values aren't a problem for my
application (it only uses floats) but we'd like to use a general
format.

3)	IEEE floating point format. This covers the entire range, is
well-specified and compact, but it's hard encoding and decoding this
(especially in portable code).

 We're also looking for/designing a format for points, and we're wondering
what people would like, especially  in terms of coordinate-system
independence. How should we encode what one 'unit' in the coordinate
space represents? Ideally, some of the FORMs we're working on will be
usable for Draw-type programs where you want to specify dimensions in
terms of some units, but our application uses pixel addressing.

 Also, is there already a structured graphics FORM, and if not what
would people like to see in it?

 I will summarize mail followups if there is any interest.
-- 
	"Hey, that's why Dad moved to Colorado. He sits Zen now.  Me, I like 
	 the mountains."
Chris Siebenmann		{allegra,mnetor,decvax,pyramid}!utgpu!radio!cks
cks@radio.toronto.edu	     or	...!utgpu!{yetti!lethe, darwin}!ontmoh!cks