/// <summary>
/// 求最近点
/// </summary>
public WPoint2D ClosestPointTo(WPoint2D P)
{
WVector2D v; /////P1到P的向量
WVector2D d; /////P1到P2向量
double dotProduct;
WVector2D alongVector;
double L;
WPoint2D Pn = Vertexs[0];
double DisMin = double.MaxValue;
WPoint2D PointMin = Vertexs[0];
double Dis;
for (int i = 0; i < Vertexs.Count - 1; i++)
{
v = Vertexs[i].VectorTo(P);
d = Vertexs[i].VectorTo(Vertexs[i + 1]);
L = d.Length;
d = d.Normalize();
dotProduct = v.DotProduct(d);
/////
if (dotProduct < 0)
{
dotProduct = 0;
}
if (dotProduct > L)
{
dotProduct = L;
}
alongVector = dotProduct * d;
Pn = Vertexs[i] + alongVector;
Dis = P.DistanceTo(Pn);
if (Dis < DisMin)
{
DisMin = Dis;
PointMin = Pn;
}
}
return(Pn);
}
/// <summary>
/// 得到点到线的距离
/// </summary>
public override double GetDistance(WPoint2D P)
{
return(P.DistanceTo(this.ClosestPointTo(P, false)));
}