/// <summary>
/// Searches for the two closests points
/// </summary>
/// <param name="intersectionPoints">List of intersection points</param>
/// <returns>The points that are closests to each other</returns>
public static ClosestPointPair ShortestDistanceBetweenCutPoints(List <Point> intersectionPoints)
{
List <ClosestPointPair> Distances = new List <ClosestPointPair>();
ClosestPointPair shortestClosest = new ClosestPointPair();
ClosestPointPair closest = new ClosestPointPair();
shortestClosest.distance = 100000;
for (int i = 0; i < intersectionPoints.Count - 1; i++)
{
for (int j = i + 1; j < intersectionPoints.Count; j++)
{
closest.point1 = intersectionPoints[i];
closest.point2 = intersectionPoints[j];
closest.distance = Math.Pow((Math.Pow((intersectionPoints[i].x - intersectionPoints[j].x), 2) + Math.Pow((intersectionPoints[i].y - intersectionPoints[j].y), 2)), 0.5);
Distances.Add(closest);
}
}
foreach (ClosestPointPair dist in Distances)
{
if (dist.distance < shortestClosest.distance)
{
shortestClosest.distance = dist.distance;
shortestClosest.point1 = dist.point1;
shortestClosest.point2 = dist.point2;
}
}
return(shortestClosest);
}
/// <summary>
/// Calculates the centroid of the cluster
/// </summary>
/// <param name="crossings">The obtained cutting points</param>
/// <returns></returns>
private static Point Cluster(List <Point> crossings, int anchors)
{
List <Point> cluster = new List <Point>();
Point centroid = new Point();
//first pass.
ClosestPointPair closestPointPair = new ClosestPointPair();
//get the two closest intersection point
closestPointPair = GeometryHelper.ShortestDistanceBetweenCutPoints(crossings); // get struct back
//add these points to the cluster
cluster.Add(new Point(closestPointPair.point1.x, closestPointPair.point1.y));
cluster.Add(new Point(closestPointPair.point2.x, closestPointPair.point2.y));
//remove them from the intersection
crossings.Remove(closestPointPair.point1);
crossings.Remove(closestPointPair.point2);
centroid.x = (cluster[0].x + cluster[1].x) / 2;
centroid.y = (cluster[0].y + cluster[1].y) / 2;
crossings.Add(centroid);
while (cluster.Count < anchors && crossings.Count > 0)
{
Point closestPoint = GeometryHelper.ShortestDistanceBetweenCutPoints(crossings, centroid);
cluster.Add(closestPoint);
crossings.Remove(closestPoint);
Point tempCentroid = new Point();
foreach (Point clusterPoint in cluster)
{
tempCentroid.x += clusterPoint.x;
tempCentroid.y += clusterPoint.y;
}
tempCentroid.x /= cluster.Count;
tempCentroid.y /= cluster.Count;
centroid = tempCentroid;
}
return(centroid);
}