Hi,
I've developed an algorithm for fitting smooth curves (the curves are like in Spiro, but piecewise-linear curvature) to user sketches. I'm thinking that this could be useful in Inkscape as a replacement or alternative to the current pencil tool algorithm. Compared to existing stuff, the benefit is that the curves are usually much nicer, the drawback is that it's a complicated algorithm and is slower--fitting a curve of moderate complexity will likely take about 1 second.
Would the Inkscape devs be potentially interested in including this functionality? I'm looking into rewriting my research prototype to be faster, cleaner, more robust, and to remove proprietary dependencies. I can write the library that does the fitting, but I'm unfamiliar with Inkscape's code base, so I'd need help integrating it in. The time frame is that I'd likely be done with the library by the middle of summer.
My paper with details and comparisons to existing methods (including Inkscape) at the end is at http://www.mit.edu/~ibaran/curves/ The reported timings can probably be improved by close to a factor of 2.
Thanks,
-Ilya