title: Creating CSS circles in react-native
body: <p>I'm having some trouble creating CSS circles in react-native.  The following works in iPhone 6 Plus but in all the other iPhones, they become diamonds.</p>
  <pre><code>circle: {
    height: 30,
    width: 30,
    borderRadius: 30,
  }
  </code></pre>
  <p>Now if I use PixelRatio on <code>borderRadius</code> it works in everything but iPhone 6 plus.  iPhone 6 plus renders it as boxes with rounded corners.</p>
  <pre><code>circle: {
    height: 30,
    width: 30,
    borderRadius: 30 / PixelRatio.get(),
  }
  </code></pre>