一个坐标点围绕任意中心点旋转--C#实现

/// <summary>  
        /// 对一个坐标点按照一个中心进行旋转  
        /// </summary>  
        /// <param name="center">中心点</param>  
        /// <param name="p1">要旋转的点</param>  
        /// <param name="angle">旋转角度，笛卡尔直角坐标</param>  
        /// <returns></returns>  
        private  Point PointRotate(Point center, Point p1, double angle)  
        {  
            Point tmp = new Point();  
            double angleHude = angle * Math.PI / 180;/*角度变成弧度*/  
            double x1 = (p1.X - center.X) * Math.Cos(angleHude) + (p1.Y - center.Y ) * Math.Sin(angleHude) + center .X;  
            double y1 = -(p1.X - center.X) * Math.Sin(angleHude) + (p1.Y - center.Y) * Math.Cos(angleHude) + center.Y;  
            tmp.X = (int)x1;  
            tmp.Y = (int)y1;  
            return tmp;  
        }