.usesLineFragmentOrigin绘图选项不能按照它在文档中的描述所假设的那样工作

Question

这里我试图通过调用它的draw（使用rect：options：context :)函数并将选项参数设置为NSStringDrawingOptions.usesLineFragmentOrigin来绘制NSAttributeString。实际上，是的，NSAttributeString绘制它的字符串，但是如果在draw中更改rect参数（使用rect：options：context :) fucntion，则更小的框架MSAttributeString只会削减它的部分就可以了。但是根据{{​​3}}

中的.usesLineFragmentOrigin说明

  

如果在options中指定了usesLineFragmentOrigin，它将包装该字符串   文本根据需要使其适合。如果字符串太大而不适合   完全在矩形内部，该方法缩放字体或调整   字母间距使字符串适合给定的边界。   这是我的代码：

 class ViewController: UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    let anotheR: anotherView = anotherView(frame: view.bounds)
    view.backgroundColor = UIColor.yellow
    view.addSubview(anotheR)
    anotheR.backgroundColor = UIColor.lightGray
    anotheR.draw(CGRect(x: 100, y: 300, width: 50, height: 10))

}


override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


}

class anotherView: UIView {

override func draw(_ rect: CGRect) {
    frame = CGRect(x: 0, y: 0, width: 500, height: 500)
    let suprect = rect
 var string = "Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s." as NSString
    let attributedString = NSMutableAttributedString(string: string as String)

    layer.borderColor = UIColor.red.cgColor
    layer.borderWidth = 2
 let context =   NSStringDrawingContext()
    context.minimumScaleFactor = 0.1
    attributedString.draw(with: CGRect(x: 20, y: 100, width: 80, height: 300), options:    NSStringDrawingOptions.usesLineFragmentOrigin , context: context)


}
}

但是，不，似乎没有做到这一点。也许某个地方我错了？也许它应该以其他方式工作？如果有人知道，请给我一个线索。谢谢！