title: Adjust line background in UITextView base on text size
body: <p>I'm having a problem here with this one, I have a <code>UITextView</code> that has a Yellow Pad Paper like background. but what I really wanted is to have a DYNAMIC LINES in that background... If I adjust the font size of the text or press ENTER, the YELLOW LINES should also adjust base on how big or small the text is. See screen shot of what I've achieved so far.</p>
  
  <p><img src="https://i.stack.imgur.com/5DOos.png" alt=""></p>
  
  <p>I need to know what framework should I study to achieve this one.</p>