title: Is it possible to get color gradients under curve in matplotlib?
body: <p>I happened to see a beautiful graph on this <a href="http://hackaday.com/2015/01/28/raspberry-pi-learns-how-to-control-a-combustion-engine/#more-145076" rel="noreferrer">page</a> which is shown below:</p>
  
  <p><img src="https://i.stack.imgur.com/Ldrog.png" alt="enter image description here"></p>
  
  <p>Is it possible to get such color gradients in matplotlib?</p>