/// <summary>
/// For all DirectedEdges in result, form them into MaximalEdgeRings.
/// </summary>
/// <param name="dirEdges"></param>
/// <returns></returns>
private IList BuildMaximalEdgeRings(IEnumerable dirEdges)
{
IList maxEdgeRings = new ArrayList();
for (IEnumerator it = dirEdges.GetEnumerator(); it.MoveNext(); )
{
DirectedEdge de = (DirectedEdge)it.Current;
if (!de.IsInResult || !de.Label.IsArea()) continue;
// if this edge has not yet been processed
if (de.EdgeRing != null) continue;
MaximalEdgeRing er = new MaximalEdgeRing(de, _geometryFactory);
maxEdgeRings.Add(er);
er.SetInResult();
}
return maxEdgeRings;
}
/// <summary>
/// Form <see cref="DirectedEdge" />s in graph into Minimal EdgeRings.
/// (Minimal Edgerings must be used, because only they are guaranteed to provide
/// a correct isHole computation).
/// </summary>
/// <param name="dirEdges"></param>
/// <returns></returns>
private IList BuildEdgeRings(IList dirEdges)
{
IList edgeRings = new ArrayList();
foreach (DirectedEdge de in dirEdges)
{
// if this edge has not yet been processed
if (de.IsInResult && de.EdgeRing == null)
{
MaximalEdgeRing er = new MaximalEdgeRing(de, _geometryFactory);
er.LinkDirectedEdgesForMinimalEdgeRings();
IList minEdgeRings = er.BuildMinimalRings();
foreach(object o in minEdgeRings)
edgeRings.Add(o);
}
}
return edgeRings;
}