Clip Arc To Cell

[r-barnes]

Is there a way to clip a great circle arc to a cell?

I see two potential approaches.

1. Use S2::GetIntersection to find intersections between cell edges and the arc. Perform additional checks to make sure that the intersection is actually on the arcs (since it appears GetIntersection returns a nearby great circle intersection). Choose two intersections appropriately.

2. Use bool ClipEdge(const R2Point& a, const R2Point& b, const R2Rect& clip, R2Point* a_clipped, R2Point* b_clipped); somehow; however, this requires projecting the cell and the arc into the uv plane and I'm not sure what the precision loss will be.

[jmr]

Again, what is the higher level problem you're trying to solve? It seems like you might be working at too low a level. There might be other tools that solve your problem, but I don't know what your real problem is.