Gradually clear how the enlarged picture

On the iPad app, "Chinese newspapers."

① Display page newspaper, the newspaper will gradually clear, this is how to achieve?
② newspaper after amplification, amplified newspapers will gradually clear, this is how to achieve?

In fact, want to ask this now popular amplified gradually clear picture of how to achieve.
Reply:
Use a different picture.
Reply:
It is a small piece of a small piece of clear ah.
Reply:
UIImageView composed by a number of screens,
Followed by a UIScrollView.
When detecting the stretching operation, first change the size of the ImageView, then blur, then a clear picture background download, download after replacing up.
Reply:
Picture is cut points.
Reply:
CATiledLayer
Take a big say, though never tried, but he said never missed.