怎么垂直放置标签，条形区域显示名字

如图，我想垂直显示UILabel，像正常的图片有100.200.300.400那样，Calculate Graph垂直对齐，显示标签如Risk那样。

可以旋转标签哦：

label.transform = CGAffineTransformMakeRotation(M_PI_2*3); // 90 degress

 CGFloat DegreesToRadians(CGFloat degrees)
{
 return degrees * M_PI / 180;
};

 CGAffineTransform transform = CGAffineTransformMakeRotation(-DegreesToRadians(90));
 label.transform = transform;