/// <summary>
/// Convert this line segment to a path. Instert some new points.
/// </summary>
/// <param name="ExtraPoints">the number of extra points to insert.</param>
/// <returns>the path.</returns>
public Point2DCollection ToPath(int ExtraPoints)
{
if (ExtraPoints < 0)
{
throw (new ArgumentException());
}
Point2DCollection points = new Point2DCollection();
points.Add(this.FirstPoint);
for (int i = 1; i <= ExtraPoints; i++)
{
double d = (double) i / (double) (ExtraPoints + 1);
points.Add(this.GetPoint(d));
}
points.Add(this.LastPoint);
return points;
}
/// <summary>
/// Divide a polygon by a path.(point2DCollection)
/// </summary>
/// <param name="path">the path.</param>
/// <param name="polygon">the polygon to divide.</param>
public void DividedBy(Point2DCollection path, Polygon2D polygon)
{
int a = polygon.HasVertex(path.FirstPoint);
int b = polygon.HasVertex(path.LastPoint);
if (a == Polygon2D.NoSuchPoint || b == Polygon2D.NoSuchPoint)
{
throw (new ArgumentException());
}
if (a > b)
{
int tmp = a;
a = b;
b = tmp;
}
Point2DCollection p2 = new Point2DCollection();
Point2DCollection p1 = new Point2DCollection();
for (int i = 0; i < polygon.VertexCount; i++)
{
if (i <= a || i >= b)
{
p1.Add(polygon.GetPoint(i));
}
if (i >= a && i <= b)
{
p2.Add(polygon.GetPoint(i));
}
}
for (int i = 1; i < path.Count - 1; i++)
{
p1.Add(path[i], a + i);
p2.Add(path[i], 0);
Parent.AddInner(path[i]);
}
if (p1.Count > p2.Count)
{
SubDivision.Add(new Polygon2D(p1));
SubDivision.Add(new Polygon2D(p2));
}
else
{
SubDivision.Add(new Polygon2D(p2));
SubDivision.Add(new Polygon2D(p1));
}
}
/// <summary>
/// Divide a sub polygon by a line segment.
/// </summary>
/// <param name="lineSegment">the line segment.</param>
/// <param name="poly">the polygon to divide.</param>
/// <returns>one of the sub polygon divided from the polygon.</returns>
internal Polygon2D DividedBy(LineSegment2D lineSegment, Polygon2D poly)
{
if (poly.isDiagonal(lineSegment))
{
int a = poly.HasVertex(lineSegment.FirstPoint);
int b = poly.HasVertex(lineSegment.LastPoint);
if (a > b)
{
int tmp = a;
a = b;
b = tmp;
}
Point2DCollection p2 = new Point2DCollection(b - a + 1);
Point2DCollection p1 = new Point2DCollection(poly.VertexCount - p2.Size + 2);
for (int i = 0; i < poly.VertexCount; i++)
{
if (i <= a || i >= b)
{
p1.Add(poly.GetPoint(i));
}
if (i >= a && i <= b)
{
p2.Add(poly.GetPoint(i));
}
}
if (p1.Count > p2.Count)
{
SubDivision.Add(new Polygon2D(p1));
return new Polygon2D(p2);
}
else
{
SubDivision.Add(new Polygon2D(p2));
return new Polygon2D(p1);
}
}
else if (lineSegment.Intersects(poly))
{
Point2DCollection Points = new Point2DCollection(2);
for (int i = 0; i < poly.VertexCount; i++)
{
LineSegment2D border = poly.GetEdge(i);
Point2D p = lineSegment.GetIntersectPoint(border);
if (p.isRegular)
{
Points.DistinctAdd(p);
}
}
Debug.Assert(Points.Count == 2);
if (poly.HasVertex(Points[0]) == Polygon2D.NoSuchPoint)
{
poly.Add(Points[0], poly.OnEdge(Points[0]));
Parent.AddInner(Points[0]);
this.InnerPoints.DistinctAdd(Points[0]);
}
if (poly.HasVertex(Points[1]) == Polygon2D.NoSuchPoint)
{
poly.Add(Points[1], poly.OnEdge(Points[1]));
Parent.AddInner(Points[1]);
this.InnerPoints.DistinctAdd(Points[1]);
}
LineSegment2D line = new LineSegment2D(Points[0], Points[1]);
return DividedBy(line, poly);
}
else
{
return poly;
}
}
private Polygon2D FlipArea(GhostTriangle2D a, GhostTriangle2D b, Polygon2D poly)
{
if (!isNeighbor(a, b))
{
throw (new ArgumentException());
}
Map(a, b);
Point2DCollection points = new Point2DCollection(4);
points.Add(poly.GetPoint(a.C));
points.Add(poly.GetPoint(a.A));
points.Add(poly.GetPoint(b.C));
points.Add(poly.GetPoint(b.B));
Polygon2D polygon = new Polygon2D(points);
return polygon;
}