How to add CIFilter to CALayer

Answer 1

There is no CIFilter in iPhone OS. There is CAFilter but it is a private API so using it on AppStore apps means rejection. If you already know what images you will use, you could create the blurred image in the first place.

See How to implement a box or gaussian blur on iPhone on how to implement a Gaussian blur filter "legally".

See CAFilter — iPhone Development Wiki on how to apply a blur filter on a CALayer using the private CAFilter class.