两点坐标公式 x2 = (x1 - x0)cosa - (y1 - y0)sina + x0 y2 = (x1 - x0)sina + (y1 - y0)cosa + y0
则点(x1, y1)绕原点旋转a度的新坐标是 x2 = x1cosa - y1sina y2 = x1sina + y1cosa