Oops. I haven't been able to use POP access to my email from home recently, so I didn't know about the freeze until just now, by reading it on the list archive on the website. I'll stop now :-).
But in the meantime, I have gotten the Tracing operation to a limited initial functionality. Please give it a try. It will obviously need to be tested and tweaked. It will almost certainly need an associated dialog to adjust the settings. Please defer any feature suggestions until later... we just want to get it to work.
To make it work, I embedded a copy of Potrace in Inkscape. Instead of using its full functionality of reading images and writing vectored output (that's OUR job), I just have it read the data from an <image>, and create an associated <path>.
Eventually, I will probably make a generic Tracer class, with various tracing engines referenced by it. The basic function a tracer needs to perform, is to read a GdkPixbuf, and output the d="" attribute of a <path>; as long as an engine does that, we can consider it a black box.
Sooo... give it a try. To use, load an image, select it, and choose "Trace image". That is all it takes. It will of course work much better on line art than a multicolored image. Currently, the color->line art conversion threshold is hardcoded at 50% brightness; this will of course be a future dialog item.
So. I'm quitting coding for now... going back to debugging. (Hey, I found a good bug Friday, anyway ;-)
Bob