 class VLogin:UIView
 {
     weak var controller:CLogin!
+    private let kButtonMargin:CGFloat = 20
     
     convenience init(controller:CLogin)
     {

            metrics:metrics,
            views:views))
        addConstraints(NSLayoutConstraint.constraints(
            withVisualFormat:"H:|-0-[loginButton]-0-|",
            options:[],
            metrics:metrics,
            views:views))
        addConstraints(NSLayoutConstraint.constraints(
            withVisualFormat:"V:[loginButton(40)]-10-|",
            options:[],
            metrics:metrics,
            views:views))

            "logoView":logoView,
            "loginButton":loginButton]
        
        let metrics:[String:CGFloat] = [
            "buttonMargin":kButtonMargin]
        
        addConstraints(NSLayoutConstraint.constraints(
            withVisualFormat:"H:|-0-[logoView]-0-|",
