title: Draw HSV circle at runtime
body: <p>I would like to have a color picker in my app looking like this</p>
  
  <p><img src="https://i.stack.imgur.com/Bkqjg.png" alt="Something like this"></p>
  
  <p>I've tried fill bitmap pixel by pixel, tried use canvas with <code>drawArc()</code> method. Both ways are not good for performance.</p>
  
  <p>Any ideas?</p>