title: List of supported attribute keys for NSString.sizeWithAttributes?
body: <p>iOS 7 uses <code>NSString::sizeWithAttributes</code> to calculate the size of the bounding box of an <code>NSString</code> given an <code>NSDictionary</code> of attributes. However, I can't find a resource that lists all the enumerated keys available for use in that <code>NSDictionary</code>.</p>
  
  <p>The <a href="https://developer.apple.com/library/ios/documentation/uikit/reference/NSString_UIKit_Additions/Reference/Reference.html#//apple_ref/occ/instm/NSString/sizeWithAttributes%3a">NSString UIKit Additions Reference</a> says that </p>
  
  <blockquote>
    <p>These are the same attributes that can be applied to an NSAttributedString object</p>
  </blockquote>
  
  <p>but doesn't list them, and they're not listed in the <a href="https://developer.apple.com/library/mac/documentation/cocoa/reference/foundation/classes/NSAttributedString_Class/Reference/Reference.html"><code>NSAttributedString</code> documentation</a> either.</p>
  
  <p>Also: of the available attribute keys, which are the most fundamental to sizing a multiline label? It seems that font size and line break mode are the most important, but without a list of the available options it's hard to say...</p>