private void Calc_Area(ref Edge_qt edge)
{
double x = Math.Abs(edge.MaxX - edge.minX);
double y = edge.MaxY;
edge.Area_Enve = x * y;
}
/// <summary>
/// 获得向量spnt_epnt在线段上的投影
/// </summary>
/// <param name="edge"></param>
/// <param name="spnt"></param>
/// <param name="epnt"></param>
/// <returns></returns>
private double GetVecProj(Edge_qt edge, Point_qt spnt, Point_qt epnt)
{
Point_qt p1 = edge.FromNode;
Point_qt p2 = edge.ToNode;
double e1_x = p2.X - p1.X;
double e1_y = p2.Y - p1.Y;
double e2_x = spnt.X - epnt.X;
double e2_y = spnt.Y - epnt.Y;
return((e1_x * e2_x + e1_y * e2_y) / Math.Sqrt(e1_x * e1_x + e1_y * e1_y));
}
/// <summary>
/// 获得边Edge
/// </summary>
/// <param name="stack"></param>
/// <returns></returns>
private List <Edge_qt> GetListEdge(Stack <Point_qt> stack)
{
Edge_qt edge;
List <Edge_qt> list = new List <Edge_qt>();
for (int i = 1; i < stack.Count; i++)
{
edge = new Edge_qt();
edge.FromNode = stack.ElementAt(i);
edge.ToNode = stack.ElementAt(i - 1);
list.Add(edge);
}
return(list);
}
/// <summary>
/// 得到点线距
/// </summary>
/// <param name="edge"></param>
/// <param name="pnt"></param>
/// <returns></returns>
private double GetD_PL(Edge_qt edge, Point_qt pnt)
{
double x = pnt.X;
double y = pnt.Y;
Point_qt p1 = edge.FromNode;
Point_qt p2 = edge.ToNode;
double m = p2.X - p1.X;
double n = p2.Y - p1.Y;
double fenzi = Math.Abs(n * x - n * p1.X - m * y + m * p1.Y);
double fenmu = Math.Sqrt(n * n + m * m);
return(fenzi / fenmu);
}
/**
* 以下是根据凸包得到一个最小外接矩形
* 基本思想是：根据凸包的每条边算得一个外接矩形面积，最后选取SMBR
*/
public List <Point_qt> GetSMBR()
{
Point_qt p1 = new Point_qt();
Point_qt p2 = new Point_qt();
Point_qt p3 = new Point_qt();
Point_qt p4 = new Point_qt();
List <Point_qt> list = new List <Point_qt>();
Edge_qt edge = GetBestEdge();
p1 = CalcPnt_Coor(edge.minX, edge.FromNode, edge.ToNode);
p2 = CalcPnt_Coor(edge.MaxX, edge.FromNode, edge.ToNode);
p3 = ReferencePoint_Clock(edge.MaxY, p2, p1);
p4 = ReferencePoint_unClock(edge.MaxY, p1, p2);
list.Add(p1);
list.Add(p2);
list.Add(p3);
list.Add(p4);
return(list);
}
private void Calc_Args(ref Edge_qt edge, Stack <Point_qt> stack)
{
for (int i = 0; i < stack.Count; i++)
{
double dis = GetD_PL(edge, stack.ElementAt(i));
if (dis > edge.MaxY)
{
edge.MaxY = dis;
}
double mx = GetVecProj(edge, stack.ElementAt(i));
if (mx < 0 && mx < edge.minX)
{
edge.minX = mx;
edge.minXNode = stack.ElementAt(i);
}
else if (mx > 0 && mx > edge.MaxX)
{
edge.MaxX = mx;
edge.MaxXNode = stack.ElementAt(i);
}
}
}
