QNurbsEditor is a 2D curve editor based on NURBS, although the curves used are currently only uniform curves.
As special features it allows to load a raster as background to help tracing a given shape, and to load python scripts that would be invoked passing the evaluated curve as argument.
Said script has to implement a def run(arg) function, where arg is a map that can be unpacked like
curve = arg["curve"]
tangents = arg["tangents"]
tangentAngles = arg["tangentAngles"]