public DirectedEdge GetRightmostEdge()
{
IList edges = this.Edges;
int size = edges.Count;
if (size < 1)
{
return(null);
}
DirectedEdge de0 = (DirectedEdge)edges[0];
if (size == 1)
{
return(de0);
}
DirectedEdge deLast = (DirectedEdge)edges[size - 1];
int quad0 = de0.Quadrant;
int quad1 = deLast.Quadrant;
if (Quadrant.IsNorthern(quad0) && Quadrant.IsNorthern(quad1))
{
return(de0);
}
else if (!Quadrant.IsNorthern(quad0) && !Quadrant.IsNorthern(quad1))
{
return(deLast);
}
else
{
// edges are in different hemispheres - make sure we return one that is non-horizontal
if (de0.Dy != 0)
{
return(de0);
}
else if (deLast.Dy != 0)
{
return(deLast);
}
}
Debug.Assert(false, "Should never reach here: found two horizontal edges incident on node");
return(null);
}
/// <summary>
/// The coordinate pairs match if they define line segments lying in
/// the same direction.
/// E.g. the segments are parallel and in the same quadrant
/// (as opposed to parallel and opposite!).
/// </summary>
private bool MatchInSameDirection(Coordinate p0, Coordinate p1,
Coordinate ep0, Coordinate ep1)
{
if (!p0.Equals(ep0))
{
return(false);
}
if (CGAlgorithms.ComputeOrientation(p0, p1, ep1) ==
OrientationType.Collinear &&
Quadrant.GetQuadrant(p0, p1) ==
Quadrant.GetQuadrant(ep0, ep1))
{
return(true);
}
return(false);
}