title: Swift 4 iOS - Completely override system font without compromising storyboard font size
body: <p>I would like to:</p>
  
  <ol>
  <li>override the default font in all the application choosing the font size from the storyboard</li>
  <li>if possibile see a preview of the custom font in the text visualized in the storyboard.<br/></li>
  </ol>
  
  <p>I managed to insert the custom font but I have problems in the texts sizing.</p>
  
  <p>I tried the following solutions but they still don't completely fit my requirements:</p>
  
  <ol>
  <li>Added this row in the <code>AppDelegate</code> inside the didFinishLaunchingWithOptions func:<br/> <code>UILabel.appearance().font = UIFont(name: "yourFont", size: yourSize)</code><br/>
  this overrides font for all UILabels but it overrides the font size too.
  All labels comes with the same <code>yourSize</code> font size.</li>
  <li><p>I extended the UILabel forcing it executing changeFontName.<br/></p>
  
  <pre><code>extension UILabel {
      override open func awakeFromNib() {
          super.awakeFromNib()
          changeFontName()
      }
  
      func changeFontName() {
          self.font = UIFont(name: "yourFont", size: self.font.pointSize)
      }
  }
  </code></pre>
  
  <p>This is working but storyboard obviously does not update the view. And I'm not sure that it is the proper way of doing it</p></li>
  </ol>