Looking for a trackball interface

[Raymond Yee]

	I am looking for some advice on programming a good user interface
(I'm using IRIX version 3.2).  I have used the trackball routines (found in
4Dgifts) in some of my C programs -- I like how it works.  I do have two
questions though:

1)  Are there people out there with better interface routines that they
would like to share with others? (in either Fortran or C)

2)  Does anyone have a Fortran version of trackball?  (I have to modify
a Fortran program and I don't want to rewrite the whole thing in C)

	Any help would be much appreciated.

Raymond Yee
(raymond at cavebear.berkeley.edu)