/*Douglas-Peucker line simplification algorithm
* INPUT: A set of points P in sequence and a tolerance value
* OUTPUT: A simplified chain after removing some of the points from P
*/
public static void PolygonalChainSimplification(Microsoft.Msagl.Core.Geometry.Point[] PointList, int start, int end, double epsilon)
{
// Find the point with the maximum distance
double dmax = 0, d = 0;
int index = 0;
for (int i = start + 1; i <= end - 1; i++)
{
d = PointToSegmentDistance.GetDistance(PointList[start], PointList[end], PointList[i]);
if (d > dmax)
{
index = i;
dmax = d;
}
}
// If max distance is greater than epsilon, recursively simplify
if (dmax > epsilon)
{
// Recursive call
PolygonalChainSimplification(PointList, start, index, epsilon);
PolygonalChainSimplification(PointList, index, end, epsilon);
}
else
{
for (int i = start + 1; i <= end - 1; i++)
{
PointList[i] = new Core.Geometry.Point(-1, -1);
}
}
}
private static double GetFacewidth(List <Vertex> face)
{
int index = 0;
LineSegment[] segments = new LineSegment[face.Count];
Vertex[,] segmentVertices = new Vertex[face.Count, 2];
Vertex initialVertex = null, oldVertex = null;
Core.Geometry.Point u1, u2;
foreach (var boundaryVertex in face)
{
if (oldVertex == null)
{
initialVertex = oldVertex = boundaryVertex;
continue;
}
u1 = new Core.Geometry.Point(boundaryVertex.XLoc, boundaryVertex.YLoc);
u2 = new Core.Geometry.Point(oldVertex.XLoc, oldVertex.YLoc);
segmentVertices[index, 0] = boundaryVertex;
segmentVertices[index, 1] = oldVertex;
segments[index++] = new LineSegment(u1, u2);
oldVertex = boundaryVertex;
}
u1 = new Core.Geometry.Point(oldVertex.XLoc, oldVertex.YLoc);
u2 = new Core.Geometry.Point(initialVertex.XLoc, initialVertex.YLoc);
segmentVertices[index, 0] = initialVertex;
segmentVertices[index, 1] = oldVertex;
segments[index] = new LineSegment(u1, u2);
double facewidth = Double.MaxValue;
for (int i = 0; i < face.Count; i++)
{
for (int j = 0; j < face.Count; j++)
{
if (i == j)
{
continue;
}
if (segments[i].Start == segments[j].Start || segments[i].End == segments[j].End ||
segments[i].End == segments[j].Start || segments[i].Start == segments[j].End)
{
continue;
}
double width;
width = PointToSegmentDistance.GetDistance(segmentVertices[i, 0], segmentVertices[i, 1],
segmentVertices[j, 0]);
if (facewidth > width)
{
facewidth = width;
}
width = PointToSegmentDistance.GetDistance(segmentVertices[i, 0], segmentVertices[i, 1],
segmentVertices[j, 1]);
if (facewidth > width)
{
facewidth = width;
}
width = PointToSegmentDistance.GetDistance(segmentVertices[j, 0], segmentVertices[j, 1],
segmentVertices[i, 0]);
if (facewidth > width)
{
facewidth = width;
}
width = PointToSegmentDistance.GetDistance(segmentVertices[j, 0], segmentVertices[j, 1],
segmentVertices[i, 1]);
if (facewidth > width)
{
facewidth = width;
}
}
}
return(facewidth);
}
private static double GetFacewidth(List <Vertex> face)
{
int index = 0;
LineSegment[] segments = new LineSegment[face.Count];
#if SHARPKIT //https://code.google.com/p/sharpkit/issues/detail?id=340
throw new InvalidOperationException();
#else
Vertex[,] segmentVertices = new Vertex[face.Count, 2];
Vertex initialVertex = null, oldVertex = null;
Core.Geometry.Point u1, u2;
foreach (var boundaryVertex in face)
{
if (oldVertex == null)
{
initialVertex = oldVertex = boundaryVertex;
continue;
}
u1 = new Core.Geometry.Point(boundaryVertex.XLoc, boundaryVertex.YLoc);
u2 = new Core.Geometry.Point(oldVertex.XLoc, oldVertex.YLoc);
segmentVertices[index, 0] = boundaryVertex;
segmentVertices[index, 1] = oldVertex;
segments[index++] = new LineSegment(u1, u2);
oldVertex = boundaryVertex;
}
u1 = new Core.Geometry.Point(oldVertex.XLoc, oldVertex.YLoc);
u2 = new Core.Geometry.Point(initialVertex.XLoc, initialVertex.YLoc);
segmentVertices[index, 0] = initialVertex;
segmentVertices[index, 1] = oldVertex;
segments[index] = new LineSegment(u1, u2);
double facewidth = Double.MaxValue;
for (int i = 0; i < face.Count; i++)
{
for (int j = 0; j < face.Count; j++)
{
if (i == j)
{
continue;
}
if (segments[i].Start == segments[j].Start || segments[i].End == segments[j].End ||
segments[i].End == segments[j].Start || segments[i].Start == segments[j].End)
{
continue;
}
double width;
width = PointToSegmentDistance.GetDistance(segmentVertices[i, 0], segmentVertices[i, 1],
segmentVertices[j, 0]);
if (facewidth > width)
{
facewidth = width;
}
width = PointToSegmentDistance.GetDistance(segmentVertices[i, 0], segmentVertices[i, 1],
segmentVertices[j, 1]);
if (facewidth > width)
{
facewidth = width;
}
width = PointToSegmentDistance.GetDistance(segmentVertices[j, 0], segmentVertices[j, 1],
segmentVertices[i, 0]);
if (facewidth > width)
{
facewidth = width;
}
width = PointToSegmentDistance.GetDistance(segmentVertices[j, 0], segmentVertices[j, 1],
segmentVertices[i, 1]);
if (facewidth > width)
{
facewidth = width;
}
}
}
return(facewidth);
#endif
}
