算法问题!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

angle[i]是指XML节点数量 可以当做为3  
float x=120.0f,y=80.0f,d=200.0f,offset=15.0f,x1=0.0f,y1=0.0f;//圆形x,y坐标，半径，偏移距离，x,y方向的偏移值
            float curangle=0.0f;//当前已转的角度                int oAngle = 4;//描点偏移的度数，越小，圆弧就越圆滑。
            
            int ox=0,oy=0;//圆心坐标
            
            for(int i=0;i< angle.Length;i++)
            {
                if(i == iSelect-1)
                {
                    x1 = Convert.ToSingle(offset * Math.Cos((curangle + angle[i]/2)*Math.PI/180.0f));
                    y1 = Convert.ToSingle(offset * Math.Sin((curangle + angle[i]/2)*Math.PI/180.0f));                        
                    
                    ox = Convert.ToInt32(x + d/2 + x1);
                    oy = Convert.ToInt32(y + d/2 + y1);
                }
                else
                {
                    ox=Convert.ToInt32(x + d/2);
                    oy=Convert.ToInt32(y + d/2);
                }
以下这三个算法是在算什么那?
x1 = Convert.ToSingle(offset * Math.Cos((curangle + angle[i]/2)*Math.PI/180.0f));
ox = Convert.ToInt32(x + d/2 + x1);
oy=Convert.ToInt32(y + d/2);