macos 开发设置NSTextView行高

如何设置 NSTextView行高 ，需要用到NSLayoutManagerDelegate

 view.layoutManager?.delegate = self

添加属性设置行高的数值。

let lineHeightMultiple: CGFloat = 1.6
let font: NSFont = NSFont.systemFont(ofSize: NSFont.systemFontSize)

在代理方写入如下

    func layoutManager(_ layoutManager: NSLayoutManager, shouldSetLineFragmentRect lineFragmentRect: UnsafeMutablePointer<NSRect>, lineFragmentUsedRect: UnsafeMutablePointer<NSRect>, baselineOffset: UnsafeMutablePointer<CGFloat>, in textContainer: NSTextContainer, forGlyphRange glyphRange: NSRange) -> Bool {
        let fontLineHeight = layoutManager.defaultLineHeight(for: font)
        let lineHeight = fontLineHeight * lineHeightMultiple
        let baselineNudge = (lineHeight - fontLineHeight)
            // The following factor is a result of experimentation:
            * 0.6

        var rect = lineFragmentRect.pointee
        rect.size.height = lineHeight

        var usedRect = lineFragmentUsedRect.pointee
        usedRect.size.height = max(lineHeight, usedRect.size.height) // keep emoji sizes

        lineFragmentRect.pointee = rect
        lineFragmentUsedRect.pointee = usedRect
        baselineOffset.pointee = baselineOffset.pointee + baselineNudge

        return true
    }