title: Let User Crop Photo in iOS App
body: <p>There are several questions (and answers) concerning cropping of images/photos within an iPhone app.</p>
  
  <p>But I couldn't find an answer covering the common task of giving the user a rectangle which can be resized with a pinch gesture to letting him resize the area to cut.</p>
  
  <p>You can find this functionality in many apps (Instagram, Twitter, etc...) most likely to cut a user photo to the right proportions. So I guess there are many people with the same problem.</p>
  
  <p>Does anyone have code or tutorials to show how this task can be done?</p>