NSAttributedString 文本总是以大 lineHeight 贴在底部 [英] NSAttributedString text always sticks to bottom with big lineHeight

问题描述

我正在尝试实现来自 Sketch 的设计标签，例如我需要字体大小 = 19 和行高 = 50 的文本样式.所以我最终将 NSAttributedString 与 NSMutableParagraphStyle 一起使用，但由于文本被粘贴到 <底部的问题而停止了代码>UILabel

I'm trying to implement by-design labels coming from Sketch e.g. I need text styles with font size = 19 and line height = 50. So I ended up using NSAttributedString with NSMutableParagraphStyle but was stopped by problem with text being sticked to bottom of UILabel

我已经尝试使用 lineHeightMultiple 和 lineSpacing 但它们没有给我想要的行高，所以我最终使用了 minimumLineHeight 和 maximumLineHeight 相等

I've already tried to use lineHeightMultiple and lineSpacing but those didn't give me the line height I wanted so I ended up using minimumLineHeight and maximumLineHeight equal the same

这是我制作 NSAttributedString

    private static func makeAttributedString(
        with attributes: TextAttributes,
        text: String? = nil,
        alignment: NSTextAlignment = .center
    ) -> NSAttributedString {
        let font = UIFont(name: attributes.font.rawValue, size: attributes.fontSize)!

        let paragraph = NSMutableParagraphStyle()
        paragraph.alignment = alignment
        paragraph.paragraphSpacing = attributes.paragraph
        paragraph.minimumLineHeight = attributes.lineHeight // equal 50 in my case
        paragraph.maximumLineHeight = attributes.lineHeight // equal 50 in my case

        let attributes: [NSAttributedStringKey: Any] = [
            NSAttributedStringKey.paragraphStyle: paragraph,
            NSAttributedStringKey.foregroundColor: attributes.textColor,
            NSAttributedStringKey.kern: attributes.kern,
            NSAttributedStringKey.font: font
        ]

        return NSAttributedString(string: text ?? "", attributes: attributes)
    }

我希望结果与设计相似

但实际上得到了

注意:将高度约束设置为 50 不适用，因为我也需要多行标签，但它们存在相同的错误

Note: setting height constraint to 50 is not applicable because I also need multiline labels but there is the same bug with them

推荐答案

似乎我自己找到了一些解决方法，也许会对某人有所帮助.

Seems like I've found some workaround myself, maybe it will help someone.

该方法是关于像这样设置baselineOffset:

The method is about setting baselineOffset like this:

NSAttributedStringKey.baselineOffset: (attributes.lineHeight - font.lineHeight) / 4

像魅力一样工作:

https://i.imgur.com/a2EOf5R.png

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