title: Mac OS X: Best way to do runtime check for retina display?
body: <p>Given a Cocoa application which runs on Mac OS X 10.7 and later:</p>
  
  <p>What is the best way to check, at runtime, if your app is currently running on a Mac with at least one retina display attached?</p>
  
  <p>If checking for this sort of thing is just really wrong-headed, I fully welcome a well-reasoned explanation of why (and I will up-vote such answers if they are good).</p>
  
  <p>But I'd still like to know :).</p>
  
  <p>It seems likely you could just do a check specifically for the new Mac Book Pro "Retina" hardware (the only Mac which currently has a retina display), but I'd really prefer a more general/generic/future-proof way to check than this.</p>
  
  <p>Ideally, I'd like to know how to detect the retina display, not the specific Mac model which currently happens to ship with a retina display.</p>