title: How to remove the extra padding below an one line UILabel
body: <p>I wanna to use a <strong>UILabel</strong> to show some words which is sent from Server，these words which i set them as <strong>NSMutableAttributeString</strong> sometimes <strong>only occupy one line</strong> (only in this case, the problem comes).</p>
  
  <p>I intend to get the exact space which the label would take up,but when the label only takes up one line,and very important  — <strong>i set the NSMutableAttributeString with lineSpacing</strong> (10px,NSMutableParagraphStyle),but this，unexpectedly，
   would also works when even there is only one line here —  the problem  shows up as some extra padding below the word (i test with some chinese word,but attention: <em>if the words takes up more than one line, there is no problem</em>). and the weird
  story is — <em>if the word is purely english or Arabic numerals，the extra padding won't  exist</em>)</p>
  
  <p>the following pics may shows the problem a little clearly:</p>
  
  <p><strong>1.English words -- oneline (<em>no</em> extra padding)</strong>[test words:today 0987776]</p>
  
  <h2><a href="https://i.stack.imgur.com/Uokr1.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Uokr1.png" alt="Test with english words"></a></h2>
  
  <p><strong>2.Chinese words -- oneline (<em>some</em> extra padding)</strong>[test words:今天天气好啊!]</p>
  
  <h2><a href="https://i.stack.imgur.com/OAQFU.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/OAQFU.png" alt="Test with chinese words"></a></h2>
  
  <p>Hope someone would help .  Thx a  lot.</p>