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

            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))

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