private LineSegment2D ChooseDiviser(LineSegment2D lineSegment)
{
for (int i = 0; i < CurrentPolygon.VertexCount; i++)
{
LineSegment2D Edge = CurrentPolygon.GetEdge(i);
if (Edge == lineSegment || Edge.Intersects(lineSegment) || !Edge.LineIntersects(lineSegment))
{
continue;
}
Point2D divPoint = lineSegment.ToLine().Intersects(Edge.ToLine());
if (lineSegment.Contains(divPoint))
{
continue;
}
LineSegment2D divLine = new LineSegment2D(lineSegment.LastPoint, divPoint);
if (divLine.Contains(lineSegment.FirstPoint))
{
//divLine = new LineSegment2D(lineSegment.FirstPoint, divPoint);
continue;
}
/*if (CurrentPolygon.InflectsEdge(divLine))
* {
* int ssi = 0;
* }*/
if (!CurrentPolygon.Contains(divLine))
{
continue;
}
if (divPoint == this.LastPoint)
{
///need trace here
return(divLine);
}
if (this.isApart(divLine, this.CurrentPointIndex, this.LastPointIndex))
{
return(divLine);
}
}
return(null);
}
/// <summary>
/// Whether the line segment is inside the polygon.
/// </summary>
/// <param name="lineSegment">the line segment.</param>
/// <returns>true if contains.</returns>
public bool Contains(LineSegment2D lineSegment)
{
/*for (int i = 0; i < this.VertexCount; i++)
* {
* if (lineSegment.Contains(this.GetEdge(i)))
* {
* return false;
* }
* }*/
if (this.InflectsEdge(lineSegment))
{
return(false);
}
return(!lineSegment.Intersects(this) && this.Contains(lineSegment.MidPoint) && !this.isOnEdge(lineSegment.MidPoint));
}
/// <summary>
/// Whether ths line segment intersects a polygon.
/// </summary>
/// <param name="polygon">the polygon.</param>
/// <returns>true if intersects.</returns>
public bool Intersects(Polygon2D polygon)
{
bool bResult = false;
for (int i = 0; i < polygon.VertexCount; i++)
{
LineSegment2D lineSegment = polygon.GetEdge(i);
//bResult |= this.TrulyIntersects(polygon.GetEdge(i));
bResult |= (this.TrulyLineIntersects(lineSegment) && lineSegment.Intersects(this));
if (bResult)
{
return(true);
}
}
return(bResult);
}
/// <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;
}
}
/// <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);
}
}
/// <summary>
/// Whether the line segment is inside the polygon.
/// </summary>
/// <param name="lineSegment">the line segment.</param>
/// <returns>true if contains.</returns>
public bool Contains(LineSegment2D lineSegment)
{
/*for (int i = 0; i < this.VertexCount; i++)
{
if (lineSegment.Contains(this.GetEdge(i)))
{
return false;
}
}*/
if (this.InflectsEdge(lineSegment))
{
return false;
}
return !lineSegment.Intersects(this) && this.Contains(lineSegment.MidPoint) && !this.isOnEdge(lineSegment.MidPoint);
}