title: What are the rules for filename matching initWithNibName?
body: <p>initWithNibName on iOS is clever: it does things like automatically load different NIB for iPad instead of iPhone (although lots of people don't know this - it IS NOT DOCUMENTED in UIViewController.initWithNibName!).</p>
  
  <p>But what else can it do? The only Apple docs I've found for this explain that:</p>
  
  <ol>
  <li>It will look for and find files with ~ipad or ~iphone on the end of the name</li>
  <li>Apple <em>implies</em> that it follows the rules for automatic image filename matching</li>
  </ol>
  
  <p>But there's no link to the rules for image matching, and I can't find any explicit docs for either :(.</p>
  
  <p>Rules might include: "you get a different NIB for retina if you put @2x on the end of the filename" (I have no idea if this works).</p>
  
  <p>What I'm really looking for is a list of what rules ARE used. It would save a lot of hardcoding - repeated in almost every single app I write - if I could make more use of their intelligent name matching (e.g. if they have a "load landscape nib vs. load portrait nib")</p>