private static Point nextPointPlus(int totalNode, Point rootPoint, Point nodePoint)
{
double arc = (2.0 * Math.PI) / (totalNode);
double x = nodePoint.X;
double y = nodePoint.Y;
//normalize pP(x,y)
x -= rootPoint.X;
y -= rootPoint.Y;
double tempX = x;
//rotate pP(x,y)
x = x * Math.Cos(arc) - y * Math.Sin(arc);
y = tempX * Math.Sin(arc) + y * Math.Cos(arc);
//realize pP(x,y)
x += rootPoint.X;
y += rootPoint.Y;
nodePoint.X=(int)x;
nodePoint.Y=(int)y;
return nodePoint;
}