public Feature 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();
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);
Geometry geomRectangle = new Geometry(wkbGeometryType.wkbLinearRing);
geomRectangle.AddPoint_2D(p1.X, p1.Y);
geomRectangle.AddPoint_2D(p2.X, p2.Y);
geomRectangle.AddPoint_2D(p3.X, p3.Y);
geomRectangle.AddPoint_2D(p4.X, p4.Y);
geomRectangle.AddPoint_2D(p1.X, p1.Y);
Geometry geo = new Geometry(wkbGeometryType.wkbPolygon);
geo.AddGeometry(geomRectangle);
Feature af = new Feature(new FeatureDefn(""));
af.SetGeometry(geo);
return(af);
}
/// <summary>
/// 给每个点设置相对角度（角度为向量（or_Pnt,rela_Pnt）和（0，1）的夹角）
/// </summary>
/// <param name="or_Pnt"></param>
/// <param name="rela_Pnt"></param>
private void SetRelaAng(Point_qt or_Pnt, ref Point_qt rela_Pnt)
{
double x = rela_Pnt.X - or_Pnt.X;
double y = rela_Pnt.Y - or_Pnt.Y;
rela_Pnt.Rela_Ang = y / Math.Sqrt(x * x + y * y);
}
/// <summary>
/// 给list里边的Point设置相对角度
/// </summary>
/// <param name="or_Pnt"></param>
/// <param name="list"></param>
private void SetListPntAng(Point_qt or_Pnt, ref List <Point_qt> list)
{
Point_qt[] ar = list.ToArray();
for (int i = 0; i < list.Count; i++)
{
SetRelaAng(or_Pnt, ref ar[i]);
}
list = ar.ToList();
}
/// <summary>
/// 返回向量P1P2上距离点P1 dis处的坐标
/// </summary>
/// <param name="dis"></param>
/// <param name="p1"></param>
/// <param name="p2"></param>
/// <returns></returns>
private Point_qt CalcPnt_Coor(double dis, Point_qt p1, Point_qt p2)
{
Point_qt p = new Point_qt();
double X = p2.X - p1.X;
double Y = p2.Y - p1.Y;
double length = Math.Sqrt(X * X + Y * Y);
p.X = p1.X + (p2.X - p1.X) * dis / length;
p.Y = p1.Y + (p2.Y - p1.Y) * dis / length;
return(p);
}
/// <summary>
/// 获得向量在线段上的投影
/// </summary>
/// <param name="edge"></param>
/// <param name="pnt"></param>
/// <returns>返回值正负皆可能</returns>
private double GetVecProj(Edge_qt edge, Point_qt pnt)
{
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 = pnt.X - p1.X;
double e2_y = pnt.Y - p1.Y;
double temp = (e1_x * e2_x + e1_y * e2_y) / Math.Sqrt(e1_x * e1_x + e1_y * e1_y);
return((e1_x * e2_x + e1_y * e2_y) / Math.Sqrt(e1_x * e1_x + e1_y * e1_y));
}
/// <summary>
/// 将Geometry里的Point压入List
/// </summary>
/// <returns></returns>
private List <Point_qt> PutPoints2List()
{
Point_qt pnt_qt;
int pCnt = qtGeometry.GetPointCount();
List <Point_qt> list_pnts = new List <Point_qt>(pCnt);
for (int i = 0; i < pCnt; i++)
{
pnt_qt = new Point_qt(qtGeometry.GetX(i), qtGeometry.GetY(i), qtGeometry.GetZ(i));
pnt_qt.PID = i;
list_pnts.Add(pnt_qt);
}
return(list_pnts);
}
/// <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);
}
/// <summary>
/// 返回点p使得向量p1p和向量p1p2二维平面垂直(p1p2顺时针旋转90度得到p1p)
/// p1p的模长为M
/// </summary>
/// <param name="M"></param>
/// <param name="p1"></param>
/// <param name="p2"></param>
/// <returns></returns>
private Point_qt ReferencePoint_Clock(double M, Point_qt p1, Point_qt p2)
{
Point_qt p = new Point_qt();
Vec2 p1p2 = new Vec2(p2.X - p1.X, p2.Y - p1.Y);
Vec2 p1p = p1p2.GetCrossVec2();
if (p1p2 * p1p > 0)
{
p1p.X = -p1p.X;
p1p.Y = -p1p.Y;
}
p1p = p1p.GetUnitVec2() * M;
p.X = p1.X + p1p.X;
p.Y = p1.Y + p1p.Y;
return(p);
}
/// <summary>
/// 构建凸包的递归算法
/// </summary>
/// <param name="RelaPnt"></param>
/// <param name="stack"></param>
private void Foo(Point_qt RelaPnt, Stack <Point_qt> stack)
{
Point_qt p2 = stack.Pop();
Point_qt p1 = stack.Pop();
if (IsLeft(p1, p2, RelaPnt))
{
stack.Push(p1);
stack.Push(p2);
stack.Push(RelaPnt);
}
else
{
stack.Push(p1);
Foo(RelaPnt, stack);
}
}
/// <summary>
/// 判断点p3是否在线段p1p2左边
/// </summary>
/// <param name="p1"></param>
/// <param name="p2"></param>
/// <param name="p3"></param>
/// <returns></returns>
private bool IsLeft(Point_qt p1, Point_qt p2, Point_qt p3)
{
double x_12 = p2.X - p1.X;
double y_12 = p2.Y - p1.Y;
double x_13 = p3.X - p1.X;
double y_13 = p3.Y - p1.Y;
if ((x_12 * y_13 - y_12 * x_13) < 0)
{
return(false);
}
else
{
return(true);
}
}
/// <summary>
/// 根据QTGeometry里的点集构建顺序list
/// </summary>
/// <returns></returns>
private List <Point_qt> GetSortedList()
{
List <Point_qt> list = PutPoints2List();
if ((list[0].X - list[list.Count - 1].X) < 0.000001 && (list[0].Y - list[list.Count - 1].Y) < 0.000001)
{
list.RemoveAt(0);
}
SortByX(ref list);
orPnt = list[0]; //选出X值最小的点
list.Remove(orPnt); //移除orPnt;
SetListPntAng(orPnt, ref list); //给list里边的Point赋角度值
SortByAngl(ref list); //list按角度排序
DeleSameAng(ref list); //筛选list中角度相同的点
return(list);
}