已知圓點座標，圓上一點座標，求圓上該點在旋轉x角度後的座標？
用極座標做 x=p.cosA y=p.sinA p等於圓的半徑
變換後的座標就是 x，=p.cos（A+x） y=p.sin（A+x）
//隨便定個圓心點座標
float centerX = 100;
float centerY = 100;
float PI = 3.14159;
//已知點座標
float pointX = 200;
float pointY = 200;
//旋轉角度
float angle = 10*(-1);
//求出半徑
float px = pointX - centerX;
float py = pointY - centerY;
float r = sqrt(px*px + py*py);
//求出弧度
float l = (angle * PI)/180;
//得出新座標
float newX = (pointX - centerX) * cos(l) + (pointY - centerY) * sin(l) + centerX;
float newY = -(pointX - centerX) * sin(l) + (pointY - centerY) * cos(l) + centerY;
cout<<"newX:"<<newX<<"newY:"<<newY<<endl;