private EdgeRingCollection BuildMinimalEdgeRings(EdgeRingCollection maxEdgeRings,
EdgeRingCollection shellList, EdgeRingCollection freeHoleList)
{
EdgeRingCollection edgeRings = new EdgeRingCollection();
for (IEdgeRingEnumerator it = maxEdgeRings.GetEnumerator(); it.MoveNext();)
{
MaximalEdgeRing er = (MaximalEdgeRing)it.Current;
if (er.MaxNodeDegree > 2)
{
er.LinkDirectedEdgesForMinimalEdgeRings();
EdgeRingCollection minEdgeRings = er.BuildMinimalRings();
// at this point we can go ahead and attempt to place holes, if this EdgeRing is a polygon
EdgeRing shell = FindShell(minEdgeRings);
if (shell != null)
{
PlacePolygonHoles(shell, minEdgeRings);
shellList.Add(shell);
}
else
{
freeHoleList.AddRange(minEdgeRings);
}
}
else
{
edgeRings.Add(er);
}
}
return(edgeRings);
}
/// <summary> For all rings in the input list,
/// determine whether the ring is a shell or a hole
/// and Add it to the appropriate list.
/// Due to the way the DirectedEdges were linked,
/// a ring is a shell if it is oriented CW, a hole otherwise.
/// </summary>
private void SortShellsAndHoles(EdgeRingCollection edgeRings,
EdgeRingCollection shellList, EdgeRingCollection freeHoleList)
{
for (IEdgeRingEnumerator it = edgeRings.GetEnumerator(); it.MoveNext();)
{
EdgeRing er = it.Current;
// er.SetInResult();
if (er.IsHole)
{
freeHoleList.Add(er);
}
else
{
shellList.Add(er);
}
}
}
public EdgeRingCollection BuildMinimalRings()
{
EdgeRingCollection minEdgeRings = new EdgeRingCollection();
DirectedEdge de = startDe;
do
{
if (de.MinEdgeRing == null)
{
EdgeRing minEr = new MinimalEdgeRing(de, geometryFactory);
minEdgeRings.Add(minEr);
}
de = de.Next;
}while (de != startDe);
return(minEdgeRings);
}
/// <summary>
/// For all DirectedEdges in result, form them into MaximalEdgeRings
/// </summary>
private EdgeRingCollection BuildMaximalEdgeRings(ArrayList dirEdges)
{
EdgeRingCollection maxEdgeRings = new EdgeRingCollection();
for (IEnumerator it = dirEdges.GetEnumerator(); it.MoveNext();)
{
DirectedEdge de = (DirectedEdge)it.Current;
if (de.InResult && de.Label.IsArea())
{
// if this edge has not yet been processed
if (de.EdgeRing == null)
{
MaximalEdgeRing er = new MaximalEdgeRing(de,
geometryFactory);
maxEdgeRings.Add(er);
er.SetInResult();
}
}
}
return(maxEdgeRings);
}