KNSemiModalViewController模仿了半模态视图，并带有一些叠加动画，可以在Park Guides by National Geographic app中看到这种效果，简单拖至项目中即可运行。

功能
Works with bare UIViewController
Works with UIViewController contained inside UINavigationController
Works with UIViewController contained inside UINavigationController, contained inside UITabbarController
Auto handling of modal frame size
Auto handling of touch area for dismissal
Resizable after presenting so that keyboard related interactions are possible
Easy to understand and very small code base, only 2 files
Trivial to implement as subclass
Landscape support (not during presentation)
Only use basic CAAnimation
iPad support (experimental)

测试环境：Xcode 5.0，iOS 4.3以上