public void rotatePoint(SegmentPoint inPoint, SegmentPoint center, double angRad)
{
rotate2D(inPoint - center, angRad);
this.X = this.X + center.X;
this.Y = this.Y + center.Y;
}
private void rotate2D(SegmentPoint inPoint, double angRad)
{
//CW rotation
this.X = (double)(Math.Cos(angRad) * inPoint.X - Math.Sin(angRad) * inPoint.Y);
this.Y = (double)(Math.Sin(angRad) * inPoint.X + Math.Cos(angRad) * inPoint.Y);
}