Swift如何从字体中计算一行文本高度

I ran into an issue where I needed to animate translating a label vertically the same distance of a textField's text height. In most cases just textField.bounds.heigt but if the textField's height is bigger than the text height it will not be any good for me. So I need to know: How to calculate the line height of the string text from its UIFont?

我遇到了一个问题，我需要设置动画来垂直翻译标签与textField的文本高度相同的距离。在大多数情况下只是textField.bounds.heigt，但如果textField的高度大于文本高度，那对我来说就不会有任何好处。所以我需要知道：如何从UIFont计算字符串文本的行高？

Regarding the duplicate: There's a little bit different of what I need. that answer(which I've referenced in my answer) get the total height depending on 1) the string 2) the width 3) the font. What I needed is one line height dpending only on the font.

关于副本：我需要的东西有点不同。答案（我在答案中引用）得到总高度取决于1）字符串2）宽度3）字体。我需要的是只有字体的一行高度。

2 个解决方案

#1

UIFont has a propperty lineHeight smth like this

UIFont有这样的属性lineHeight smth

        if let font = _textView.font {
        let height = font.lineHeight
    }

where font it's your font

字体是你的字体

#2

I have been searching for a way to do that and find this answer where it has a String extension to calculate the size for the string and a given font. I have modified it to do what I want (get the line height of text written using a font.):

我一直在寻找一种方法，并找到这个答案，它有一个字符串扩展，以计算字符串和给定字体的大小。我修改它来做我想要的（获取使用字体写入的文本的行高）。

extension UIFont {

  var height:CGFloat {
    let constraintRect = CGSize(width: CGFloat.max, height: CGFloat.max)

    let boundingBox = "Anytext".boundingRectWithSize(constraintRect, options: NSStringDrawingOptions.UsesLineFragmentOrigin, attributes: [NSFontAttributeName: self], context: nil)

    return boundingBox.height
  }
}

I hope this helps someone looking for it. (may be myself in the future).

我希望这有助于有人寻找它。（未来可能是我自己）。

#1