title: Set UILabel font size according to its frame size?
body: <p>I have an application that allow user to use the pinch gesture for scaling the label
  How can I change the font size according to the new frame size so that the font just fit in the frame rectangle?</p>
  
  <p>My current step is only set the label with new transform, and the text will look blur if the label is scaled too small/large.
  I want to ensure that the label can display the text clearly where the text can have the max size according to the new frame rectangle.</p>