blur present viewcontroller

demo.swift

let vc = CustomViewController()
vc.modalTransitionStyle = UIModalTransitionStyle.CrossDissolve
vc.modalPresentationStyle = UIModalPresentationStyle.OverFullScreen
presentViewController(vc, animated: true, completion: nil)

    // in CustomViewController
    override func viewDidLoad() {
        super.viewDidLoad()
        let lightEffect = UIBlurEffect(style: .Light)
        let lightView = UIVisualEffectView(effect: lightEffect)
        view.addSubview(lightView)
        lightView.snp_makeConstraints { (make) in
            make.edges.equalTo(view)
        }
        
        
        let darkEffect = UIBlurEffect(style: .Dark)
        let darkView = UIVisualEffectView(effect: darkEffect)
        view.addSubview(darkView)
        darkView.snp_makeConstraints { (make) in
            make.edges.equalTo(view)
        }
        
    }