[iOS] UILabel获取每行内容

   extension UILabel {
    /// 字符串分行后获取每行的内容
    /// 通过富文本分行，然后通过CTframe获取每一行的内容
    func linesOfString() -> [String] {
        var strings: [String] = []
        guard let text = text,
              let font = font else { return [] }
        let attstr = NSMutableAttributedString(string: text, attributes: [NSAttributedString.Key.font: font])
        
        let paragraphStyle = NSMutableParagraphStyle()
        paragraphStyle.lineBreakMode = .byWordWrapping
        attstr.addAttribute(.paragraphStyle, value: paragraphStyle, range: NSMakeRange(0, text.count))
        
        let frameSetter = CTFramesetterCreateWithAttributedString(attstr as CFAttributedString)
        
        let path = CGMutablePath()
        path.addRect(CGRect(x: 0, y: 0, width: frame.size.width, height: 100))
        
        let frame = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, 0), path, nil)
        
        if let lines = CTFrameGetLines(frame) as? [CTLine] {
            lines.forEach({
                let linerange = CTLineGetStringRange($0)
                let range = NSMakeRange(linerange.location, linerange.length)
                let string = (text as NSString).substring(with: range)
                strings.append(string)
            })
        }
        return strings
    }
}