Swift 3.0 - funcoes

gistfile1.swift

extension UIButton{
   func addTextSpacing(spacing: CGFloat){
       let attributedString = NSMutableAttributedString(string: (self.titleLabel?.text!)!)
       attributedString.addAttribute(NSKernAttributeName, value: spacing, range: NSRange(location: 0, length: (self.titleLabel?.text!.characters.count)!))
       self.setAttributedTitle(attributedString, for: .normal)
   }
}
btnRegister.addTextSpacing(spacing: 4.5)

extension UILabel{
    func addTextSpacing(spacing: CGFloat){
        let attributedString = NSMutableAttributedString(string: self.text!)
        attributedString.addAttribute(NSKernAttributeName, value: spacing, range: NSRange(location: 0, length: self.text!.characters.count))
        self.attributedText = attributedString
    }
}
lblOne.addTextSpacing(spacing: 4.5)

extension UITextField{
    func addPlaceholderSpacing(spacing: CGFloat){
        let attributedString = NSMutableAttributedString(string: self.placeholder!)
        attributedString.addAttribute(NSKernAttributeName, value: spacing, range: NSRange(location: 0, length: self.placeholder!.characters.count))
        self.attributedPlaceholder = attributedString
    }
}
txtUserName.addPlaceholderSpacing(spacing: 4.5)

extension UINavigationItem{
    func addSpacing(spacing: CGFloat){
        let attributedString = NSMutableAttributedString(string: self.title!)
        attributedString.addAttribute(NSKernAttributeName, value: spacing, range: NSRange(location: 0, length: self.title!.characters.count))
        let label = UILabel()
        label.textColor = UIColor.black
        label.font = UIFont.systemFont(ofSize: 15, weight: UIFontWeightBold)
        label.attributedText = attributedString
        label.sizeToFit()
        self.titleView = label
    }
}
navigationItem.addSpacing(spacing: 2.5)