A couple of months ago I mentioned a nice tutorial on how to extensively customize the navigation bar with the changes in iOS 7.
Here’s an open source library allowing you create iOS 7 style bar buttons from Sebastien Windal that have very slick looking animations between them.
FRDLivelyButton uses core graphics, and the color, thickness, and animation duration can be customized. While the buttons created are meant to be bar buttons they subclass UIButton and can be used anywhere a UIButton can be used.
Here’s an image from the readme that neatly shows FRDLivelyButton in action:
You can find FRDLivelyButton on Github here.
Some very neat customized navigation bar buttons.