List<PointF> SortPoints(PointF[] points)
{
List<PointF> result = new List<PointF>();
PointF center = GetGravityPoint(points.ToList());
PointF x = new PointF(center.X+1, center.Y);
PointF OX = new PointF(1,0);
double OX_len = 1;
List<double> angle = new List<double>();
foreach (PointF point in points)
{
PointF tmpO = new PointF(point.X-center.X,point.Y-center.Y);
double tmp_len = Math.Sqrt((point.X - center.X)*(point.X - center.X)+(point.Y - center.Y)*(point.Y - center.Y));
angle.Add(Math.Asin((tmpO.X)/tmp_len));
}
List<double> tmpAngle = new List<double>(angle);
tmpAngle.Sort();
List<double> doubles = new List<double>();
for(int i = 0;i< tmpAngle.Count;i++)
{
double tmp = tmpAngle[i];
int v = angle.FindIndex(item => item.Equals(tmp));
result.Add(points[v]);
}
return result;
}
private PointF GetGravityPoint(List<PointF> lstPol)
{
double n, i;
double x1, y1, x2, y2, x3, y3;
double sum_x = 0, sum_y = 0, sum_s = 0;
x1 = lstPol[0].X;
y1 = lstPol[0].Y;
x2 = lstPol[1].X;
y2 = lstPol[1].Y;
n = lstPol.Count;
int k = 2;
for (i = 1; i <= n - 2; i++)
{
x3 = lstPol[k].X;
y3 = lstPol[k].Y;
double s = ((x2 - x1) * (y3 - y1) - (x3 - x1) * (y2 - y1)) / 2.0;
sum_x += (x1 + x2 + x3) * s;
sum_y += (y1 + y2 + y3) * s;
sum_s += s;
x2 = x3;
y2 = y3;
k++;
}
PointF center = PointF.Empty;
center.X = Convert.ToSingle(sum_x / sum_s / 3.0);
center.Y = Convert.ToSingle(sum_y / sum_s / 3.0);
//MessageBox.Show("("+center.X.ToString()+","+center.Y.ToString()+")");
return center;
}