https://developer.apple.com/library/ios/navigation/
Core Animation Guide:
https://developer.apple.com/library/ios/documentation/Cocoa/Conceptual/CoreAnimation_guide/Introduction/Introduction.html#//apple_ref/doc/uid/TP40004514
Core Image Guide:
https://developer.apple.com/library/ios/documentation/GraphicsImaging/Conceptual/CoreImaging/ci_intro/ci_intro.html