[Boost-users] [Voronoi] Trying to figure out proper direction of semi-infinite edges.

Hi, Trying to figure out how to use the Voronoi library in 1.54 Boost (Great stuff BTW, Thanks!) I am using the library to shatter a 2d convex polygon. So I need to generate polygons that are the results of clipping a voronoi cell against my convex poly. I am having hard time figuring out how to properly identify the direction of the semi-infinite edge. I know i can obtain the general direction of the infinite edge from the participating cell points, but I am not clear on how to distinguish between two possible directions in the semi-finite case. Any help would be much appreciated! Thanks! Nick.