Porting Ole Begemann CollectionViewParallaxScrolling to Swift. It will be extended to add more features.
Please read Ole's blog post here 'http://oleb.net/blog/2014/04/parallax-scrolling-collectionview/) for more information.
Checkout the gif here -
https://github.com/kNeerajPro/CGParallaxCollectionView/blob/master/ParallaxScrollingViewGif.gif
Checkout the library at http://www.learnswift.tips/ and https://www.cocoacontrols.com/controls/cgparallaxcollectionview.