計算字體寬度

/**
 * 計算寬度  內(nèi)容 字體大小
 */
public func textWidth(text: String, font: UIFont) -> CGFloat {
    //給定的最大寬度、因為計算寬度，高度無所謂
    let size = CGSize(width: 20000, height: 100) 
    let attributes =   [NSAttributedString.Key.font: font]
    let labelSize:CGRect = NSString(string: text).boundingRect(with: size, options: .usesLineFragmentOrigin, attributes: attributes, context: nil)
    return labelSize.width
}
//或者
extension String {
    /**
     * 計算字體寬度 字體大小
     */
    public func textWidth(font: UIFont) -> CGFloat {
        let str         = self as NSString
        let size        = CGSize(width: 20000, height: 100)
        let attributes  = [NSAttributedString.Key.font:  font]
        let labelSize   = str.boundingRect(with: size, options: .usesLineFragmentOrigin, attributes: attributes, context: nil).size
        return labelSize.width
    }
}

計算字體高度

/**
 * 計算高度  字體寬度  內(nèi)容（根據(jù)寬度計算高度）  字體大小
 */
public func textHeight(width: CGFloat, text: String, font: UIFont) -> CGFloat {
    let size = CGSize(width: width, height: 2000)
    let attributes =   [NSAttributedString.Key.font: font]
    let labelSize:CGRect = NSString(string: text).boundingRect(with: size, options: .usesLineFragmentOrigin, attributes: attributes, context: nil)
    return labelSize.height
}
extension String { 
    /**
     * 計算字體高度  字體寬度（根據(jù)寬度計算高度） 字體大小
     */
    public func textHeight(textWidth: CGFloat, font: UIFont) -> CGFloat {
        let str         = self as NSString
        let size        = CGSize(width: textWidth, height: 2000)
        let attributes  = [NSAttributedString.Key.font: font]
        let labelSize   = str.boundingRect(with: size, options: .usesLineFragmentOrigin, attributes: attributes, context: nil).size
        return labelSize.height
    }
}