根据文字计算高度

size.swift

let fontSize: CGFloat = 22.0

func sizeHeightWithText(labelText: NSString,
    fontSize: CGFloat,
    textAttributes: [String : Any]) -> CGRect {
        
    return labelText.boundingRect(
        with: CGSize(width:fontSize, height:480),
            options: NSStringDrawingOptions.usesLineFragmentOrigin,
            attributes: textAttributes, context: nil)
}