/// <summary>
/// Check that a ring does not self-intersect, except at its endpoints.
/// Algorithm is to count the number of times each node along edge occurs.
/// If any occur more than once, that must be a self-intersection.
/// </summary>
private void CheckNoSelfIntersectingRing(EdgeIntersectionList eiList)
{
ISet nodeSet = new HashedSet();
bool isFirst = true;
for (IEnumerator i = eiList.Iterator(); i.MoveNext();)
{
EdgeIntersection ei = (EdgeIntersection)i.Current;
if (isFirst)
{
isFirst = false;
continue;
}
if (nodeSet.Contains(ei.coord))
{
validErr = new ValidationError(
ValidationErrorType.RingSelfIntersection, ei.coord);
return;
}
else
{
nodeSet.Add(ei.coord);
}
}
}
/// <summary>
/// Creates stub edges for all the intersections in this
/// Edge (if any) and inserts them into the graph.
/// </summary>
public void ComputeEdgeEnds(Edge edge, ArrayList l)
{
EdgeIntersectionList eiList = edge.EdgeIntersectionList;
// ensure that the list has entries for the first and last point of the edge
eiList.AddEndpoints();
IEnumerator it = eiList.Iterator();
EdgeIntersection eiPrev = null;
EdgeIntersection eiCurr = null;
// no intersections, so there is nothing to do
if (!it.MoveNext())
{
return;
}
EdgeIntersection eiNext = (EdgeIntersection)it.Current;
do
{
eiPrev = eiCurr;
eiCurr = eiNext;
eiNext = null;
if (it.MoveNext())
{
eiNext = (EdgeIntersection)it.Current;
}
if (eiCurr != null)
{
CreateEdgeEndForPrev(edge, l, eiCurr, eiPrev);
CreateEdgeEndForNext(edge, l, eiCurr, eiNext);
}
}while (eiCurr != null);
}