cks@radio.toronto.edu (11/05/87)
[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!ckscarolyn@cbmvax.UUCP (Carolyn Scheppner CATS) (11/10/87)
In article <561@radio.toronto.edu> cks@radio.toronto.edu (Chris Siebenmann) writes: > > 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? >[] > Also, is there already a structured graphics FORM, and if not what >would people like to see in it? No standards exist yet, but there has been ongoing discussion in our IFF conference on BIX (amiga.dev/iff) dealing with storage of floating point and also storage of 3-D objects. Most of the big 3-D Amiga software developers are involved, but nothing concrete has developed yet. You may be able to reach some agreement on the floating point there though. -- =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Carolyn Scheppner -- CATS >>Commodore Amiga Technical Support<< UUCP ...{allegra,ihnp4,rutgers}!cbmvax!carolyn PHONE 215-431-9180 =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
jdow@gryphon.CTS.COM (Joanne Dow) (11/11/87)
In article <561@radio.toronto.edu> cks@radio.toronto.edu (Chris Siebenmann) writes: >[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? This is the itme to suffer the expenses and get on BIX and GET HEARD. This very topic is being thrashed out in the amiga.dev conference iff topic. (j amiga.dev/iff) If you do not get heard you may find yourself with a format that nobody else will support. And you'll find yourself off in the never never land of having no access to other program's data files. {@_@} Kinda commercial, I know; but, this 'un's important. -- <@_@> BIX:jdow INTERNET:jdow@gryphon.CTS.COM UUCP:{akgua, hplabs!hp-sdd, sdcsvax, ihnp4, nosc}!crash!gryphon!jdow Remember - A bird in the hand often leaves a sticky deposit. Perhaps it was better you left it in the bush with the other one.