public static int CompareByYThenX(ICoord s1, Point s2) {
if (s1.Y < s2.Y) return -1;
if (s1.Y > s2.Y) return 1;
if (s1.X < s2.X) return -1;
if (s1.X > s2.X) return 1;
return 0;
}
private static bool GetPoints(Edge edge, Criterion c, out ICoord l, out ICoord r) {
l = (c == Criterion.cVertex) ? edge.LeftVertex : edge.LeftSite as ICoord;
r = (c == Criterion.cVertex) ? edge.RightVertex : edge.RightSite as ICoord;
return l != Vertex.VertexAtInfinity && r != Vertex.VertexAtInfinity;
}