title: How can I obtain a CGColor from RGB values?
body: <p>I am trying to create a custom RGB <code>CGColor</code> using Swift to use as a border color for a <code>UIButton</code>.  I've tried following code but the color is not visible:</p>
  <pre><code>var red = UIColor(red: 100.0, green: 130.0, blue: 230.0, alpha: 1.0)
  self.layer.borderColor = red.CGColor
  </code></pre>
  <p>Is there any way to create a <code>CGColor</code> directly from RGB values?</p>