How do you adjust text kerning using Interface Builder in Xcode 7?

Question

There are a myriad of settings for NSAttributedParagraphStyle that I can see in Interface Builder:

Answer 1

Swift 5

UILabel Extension:

@IBDesignable
extension UILabel {
    @IBInspectable
      var letterSpace: CGFloat {
          set {
              let attributedString: NSMutableAttributedString!
              if let currentAttrString = attributedTitle(for: .normal) {
                  attributedString = NSMutableAttributedString(attributedString: currentAttrString)
              }
              else {
                  attributedString = NSMutableAttributedString(string: self.titleLabel?.text ?? "")
                  setTitle(.none, for: .normal)
              }

              attributedString.addAttribute(NSKernAttributeName,
                                             value: newValue,
                                             range: NSRange(location: 0, length: attributedString.length))

              setAttributedTitle(attributedString, for: .normal)
          }

          get {
              if let currentLetterSpace = attributedTitle(for: .normal)?.attribute(NSKernAttributeName, at: 0, effectiveRange: .none) as? CGFloat {
                  return currentLetterSpace
              }
              else {
                  return 0
              }
          }
      }
}

UIButton Extension

    extension UIButton{
          @IBInspectable
          var letterSpace: CGFloat {
              set {
                  let attributedString: NSMutableAttributedString!
                  if let currentAttrString = attributedTitle(for: .normal) {
                      attributedString = NSMutableAttributedString(attributedString: currentAttrString)
                  }
                  else {
                      attributedString = NSMutableAttributedString(string: self.titleLabel?.text ?? "")
                      setTitle(.none, for: .normal)
                  }
    
                attributedString.addAttribute(NSAttributedString.Key.kern,
                                                 value: newValue,
                                                 range: NSRange(location: 0, length: attributedString.length))
    
                  setAttributedTitle(attributedString, for: .normal)
              }
    
              get {
                if let currentLetterSpace = attributedTitle(for: .normal)?.attribute(NSAttributedString.Key.kern, at: 0, effectiveRange: .none) as? CGFloat {
                      return currentLetterSpace
                  }
                  else {
                      return 0
                  }
              }
          }
}