drawing interesting curves

[Paul Barton-Davis <pbd Op Net>]

I'm working on a pretty complex open source project called Quasimodo
(http://www.op.net/~pbd/quasimodo). It is a reimplementation of the
Csound music/audio/midi language with a graphical front end, designed
to be usable somewhat like a big modular synthesizer (but including a
full array of user-definable audio and midi processing modules).

I'm using gtk, for the underlying UI library (well, actually, Gtk--,
but I'm happy to ask questions only about gtk, and get only gtk answers).

I need some help - I need some ideas on how to draw representations of
"patch cords" as used on some modular synthesizers and old telephone
exchange switches. Take a look at this URL:

	 http://www.creamware.com/Andere/modular_waldorf_big.JPG

    (they changed the image recently, but its still relevant)

and you'll get a good idea of what I want my interface to look like. I
figured out most of the rest of it, but the cables, I have no idea how
to even begin. First, they are rather interesting curves whose shape
has to be computed at run-time. Second, they have a builtin "lighting
model" that helps them look pretty realistic. I have no idea how to
map the X drawing primitives, or the gdk equivalents or anything else
onto the challenge of drawing stuff like this.

Any ideas would be very helpful.

--p