private string CreateHalfEdgeString(HalfEdge he, Polygon p)
{
long edgeKey = pe.GetEdgeKey(he.Edge);
Polygon neighbor = null;
foreach (Polygon candidate in pe.EdgePolygons[edgeKey])
if (candidate != p)
neighbor = candidate;
string neighborStr = (neighbor != null) ? neighbor.Id.ToString() : "-1";
List<string> xp = new List<string>();
List<string> yp = new List<string>();
Point[] points = he.GetPoints();
foreach (Point op in points)
{
PointF cp = ConvertPoint(op);
xp.Add(cp.X.ToString(CultureInfo.InvariantCulture));
yp.Add(cp.Y.ToString(CultureInfo.InvariantCulture));
}
string xPoints = String.Join(",", xp);
string yPoints = String.Join(",", yp);
return "{\"neighbor\": " + neighborStr + ", \"xpoints\": [" + xPoints + "], \"ypoints\": [" + yPoints + "]}";
}
private double GetOutgoingHalfEdgeAngle(HalfEdge he)
{
var points = he.Edge.Points;
Line line;
if (he.Start.X == points[0].X && he.Start.Y == points[0].Y)
line = new Line(new Point(he.Start.X, he.Start.Y), new Point(points[1].X, points[1].Y));
else
line = new Line(new Point(he.Start.X, he.Start.Y), new Point(points[points.Count - 2].X, points[points.Count - 2].Y));
return line.Angle();
}
private HalfEdge FindNextHalfEdge(HalfEdge inEdge)
{
int nodeKey = GetNodeKey(inEdge.End);
List<HalfEdge> outgoingEdges = new List<HalfEdge>(NodeHalfEdges[nodeKey]);
int counterPart = -1;
for (int i=0; i<outgoingEdges.Count; i++)
if (outgoingEdges[i].Edge == inEdge.Edge)
counterPart = i;
double inAngle = FixAngle(GetHalfEdgeAngle(outgoingEdges[counterPart]));
outgoingEdges.RemoveAt(counterPart);
double[] angles = new double[outgoingEdges.Count];
int greater = -1, smaller = -1;
for (int i=0; i<angles.Length; i++)
{
angles[i] = FixAngle(GetHalfEdgeAngle(outgoingEdges[i]));
if (angles[i] > inAngle)
greater = i;
if (angles[i] < inAngle)
smaller = i;
}
if (greater >= 0)
{
for (int i = 0; i<angles.Length; i++)
if (angles[i] > inAngle && angles[i] < angles[greater])
greater = i;
return outgoingEdges[greater];
}
if (smaller >= 0)
{
for (int i = 0; i < angles.Length; i++)
if (angles[i] < inAngle && angles[i] < angles[smaller])
smaller = i;
return outgoingEdges[smaller];
}
return null;
}
private void AddHalfEdge(HalfEdge he)
{
HalfEdges.Add(he);
int key = GetNodeKey(he.Start);
if (NodeHalfEdges.ContainsKey(key))
NodeHalfEdges[key].Add(he);
else
{
List<HalfEdge> list = new List<HalfEdge>();
list.Add(he);
NodeHalfEdges.Add(key, list);
}
}
public long GetHalfEdgeKey(HalfEdge he)
{
return GetHalfEdgeKey(he.Start, he.End);
}
public HalfEdge FindNextUnvisitedHalfEdge(HalfEdge halfEdge, Dictionary<long,bool> vistedHalfEdges)
{
HalfEdge nextHalfEdge = FindNextHalfEdge(halfEdge);
if (nextHalfEdge == null)
return null;
long nextHalfEdgeKey = GetHalfEdgeKey(nextHalfEdge);
if (vistedHalfEdges.ContainsKey(nextHalfEdgeKey))
return null;
else
return nextHalfEdge;
}
