swift 估计字符串的高度和宽度

Posted 2021-05-19

extension String {
    func height(withConstrainedWidth width: CGFloat, font: UIFont) -> CGFloat {
        let constraintRect = CGSize(width: width, height: .greatestFiniteMagnitude)
        let boundingBox = self.boundingRect(with: constraintRect, options: .usesLineFragmentOrigin, attributes: [NSAttributedString.Key.font: font], context: nil)
        
        return ceil(boundingBox.height)
}

    func width(withConstrainedHeight height: CGFloat, font: UIFont) -> CGFloat {
        let constraintRect = CGSize(width: .greatestFiniteMagnitude, height: height)
        let boundingBox = self.boundingRect(with: constraintRect, options: .usesLineFragmentOrigin, attributes: [NSAttributedString.Key.font: font], context: nil)
        
        return ceil(boundingBox.width)
    }
}