Dynamic graphs under gtk or other widget set

[Tom Huckstep]

Hello,

I would like to write a mathematical function graph
plotting program in python with the capability to draw
`dynamic' graphs.  I'll explain what I mean by dynamic:

In order to plot functions of two variables, one variable,
x, say, will change as you move along the x-axis, but the
other, a, say, will change with time.  A graph of
f(x,a) = ax will be represented as a straight line that
gets steeper with time.

If possible I would like to do this with gtk, because I
would like to modify a program I have found that already
plots `static' graphs, but if this isn't possible I'd be
happy to use any widget set.

My first thought, after browsing through some tkinter
demos (notably brownian.py), was to use threading to
implement this.  I gave it a quick try, but it didn't
seem to work, probably because of the way that the rest
of the code is organised.

Has anyone any ideas of a convenient way to manage this?

Tom

P.S.  If anyone knows of a program (in python or
otherwise) that already implements this it would be handy
to find out about it.