gtk drawing: simple layers

[Allin Cottrell <cottrell wfu edu>]

I have a pixmap displayed in a gdk window.  Now I'd
like to superimpose a rectangle to give the user
feedback on the area she has selected with a mouse
drag -- a 'wire frame' rectangle that doesn't cover
up the pixmap.

Any pointers to examples of this sort of thing would
be appreciated. I know it's done in Gimp, but Gimp is
rather complicated; if there's a simpler example
that would be great.

Allin Cottrell
Wake Forest University