title: width and height in presentPopoverFromRect?
body: <p>In <strong><code>presentPopoverFromRect:inView:permittedArrowDirections:animated:</code></strong>, method of <strong><code>UIPopoverViewController</code></strong>, for "<strong><code>presentPopoverFromRect</code></strong>", what I have understood is that "<strong><code>x</code></strong>" and "<strong><code>y</code></strong>" are where it will point its anchor but what "<strong><code>width</code></strong>" and "<strong><code>height</code></strong>" parameter will do?</p>
  
  <p>I am playing with them by setting different values and result is very confusing.</p>