title: How to detect host app is in Zoom mode or Normal mode in iPhone 6 Plus?
body: <p>Assume iPhone 6 Plus display is in standard mode (Settings > Display > View > Standard), the <code>UIInputViewController</code> <code>inputView</code> of a keyboard extension returns different widths depends on whether the host app is optimised for the iPhone 6/iPhone 6 Plus screen. </p>
  
  <p>For example, the built-in Notes app returns width as 414 points (not zoomed), where the LINE app (as of v4.7.2) returns 320 points (zoomed). </p>
  
  <p>How can a keyboard extension determine the width of the host app window (say, in <code>viewDidLoad</code>,  before <code>viewDidiLoad</code>)?</p>