title: What do setDither,setFilterBitmap and setAntiAlias do in a Canvas?
body: <p>Usually samples that I see,use this methods when try to draw bitmaps on canvas.<a href="https://stackoverflow.com/a/4294195/1043882">For example</a>:</p>
  
  <pre><code>paint.setAntiAlias(true);
  paint.setFilterBitmap(true);
  paint.setDither(true);
  </code></pre>
  
  <p>But I do not know what those three methods do?When I have to use them?</p>