Anti-Aliased 2D drawing

[Scott Robert Ladd <gnome coyotegulch com>]

I'm working on a program that draws relatively simple diagrams --
involving lines of different styles and a few arcs -- on top of a base
PNG image. Doing this using the standard GTK facilities isn't difficult,
but the result is... well, rather rough (jagged, actually). As I
understand it, Gtk+ does not support anti-aliasing natively.

I've been experimenting with GtkDrawingArea and GtkImage,
but I'd appreciate any advice on drawing high-quality simple figures in
a GtkWidget.

While I want to keep dependencies to a minimum, it looks like I need to
use an external library. I've found Cairo (http://cairographics.org)
and, of course, libart.

My interest is in finding the simplest and most universal solution.
Cairo looks interesting, but seems to still be in early beta. And, of
course, there's libart. I've heard that Cairo might be integrated into
Gtk at some point.

Thank you in advance for helpful comments.

..Scott