private static void ComputeNextCWEdges(Node node)
{
DirectedEdgeStar deStar = node.OutEdges;
PolygonizeDirectedEdge startDE = null;
PolygonizeDirectedEdge prevDE = null;
// the edges are stored in CCW order around the star
for (IEnumerator i = deStar.Edges.GetEnumerator(); i.MoveNext();)
{
PolygonizeDirectedEdge outDE = (PolygonizeDirectedEdge)i.Current;
if (outDE.Marked)
{
continue;
}
if (startDE == null)
{
startDE = outDE;
}
if (prevDE != null)
{
PolygonizeDirectedEdge sym = (PolygonizeDirectedEdge)prevDE.Sym;
sym.Next = outDE;
}
prevDE = outDE;
}
if (prevDE != null)
{
PolygonizeDirectedEdge sym = (PolygonizeDirectedEdge)prevDE.Sym;
sym.Next = startDE;
}
}
/// <summary>
///
/// </summary>
/// <param name="node"></param>
private static void ComputeNextCWEdges(Node node)
{
DirectedEdgeStar deStar = node.OutEdges;
PolygonizeDirectedEdge startDE = null;
PolygonizeDirectedEdge prevDE = null;
// the edges are stored in CCW order around the star
foreach (PolygonizeDirectedEdge outDE in deStar.Edges)
{
if (outDE.IsMarked)
{
continue;
}
if (startDE == null)
{
startDE = outDE;
}
if (prevDE != null)
{
PolygonizeDirectedEdge sym = (PolygonizeDirectedEdge)prevDE.Sym;
sym.Next = outDE;
}
prevDE = outDE;
}
if (prevDE != null)
{
PolygonizeDirectedEdge sym = (PolygonizeDirectedEdge)prevDE.Sym;
sym.Next = startDE;
}
}
/// <summary>
/// Computes the next edge pointers going CCW around the given node, for the
/// given edgering label.
/// This algorithm has the effect of converting maximal edgerings into minimal edgerings
/// </summary>
/// <param name="node"></param>
/// <param name="label"></param>
private static void ComputeNextCCWEdges(Node node, long label)
{
DirectedEdgeStar deStar = node.OutEdges;
//PolyDirectedEdge lastInDE = null;
PolygonizeDirectedEdge firstOutDE = null;
PolygonizeDirectedEdge prevInDE = null;
// the edges are stored in CCW order around the star
IList edges = deStar.Edges;
//for (IEnumerator i = deStar.Edges.GetEnumerator(); i.MoveNext(); ) {
for (int i = edges.Count - 1; i >= 0; i--)
{
PolygonizeDirectedEdge de = (PolygonizeDirectedEdge)edges[i];
PolygonizeDirectedEdge sym = (PolygonizeDirectedEdge)de.Sym;
PolygonizeDirectedEdge outDE = null;
if (de.Label == label)
{
outDE = de;
}
PolygonizeDirectedEdge inDE = null;
if (sym.Label == label)
{
inDE = sym;
}
if (outDE == null && inDE == null)
{
continue; // this edge is not in edgering
}
if (inDE != null)
{
prevInDE = inDE;
}
if (outDE != null)
{
if (prevInDE != null)
{
prevInDE.Next = outDE;
prevInDE = null;
}
if (firstOutDE == null)
{
firstOutDE = outDE;
}
}
}
if (prevInDE != null)
{
Assert.IsTrue(firstOutDE != null);
prevInDE.Next = firstOutDE;
}
}
/// <summary>
///
/// </summary>
private void FindRightmostEdgeAtNode()
{
Node node = minDe.Node;
DirectedEdgeStar star = (DirectedEdgeStar)node.Edges;
minDe = star.GetRightmostEdge();
// the DirectedEdge returned by the previous call is not
// necessarily in the forward direction. Use the sym edge if it isn't.
if (!minDe.IsForward)
{
minDe = minDe.Sym;
minIndex = minDe.Edge.Coordinates.Length - 1;
}
}
