Cannot set image background

[arcioneo]

Hi, this is an awesome tool, thanks for that.

I tried to set a background image view(already done before) like this:

let backgroundImage = UIImage(named: imageName)
let backgroundView = UIImageView(image: backgroundImage)
backgroundView.frame = signatureViewController.view.frame       
signatureViewController.view.addSubview(backgroundView)
signatureViewController.view.sendSubviewToBack(backgroundView)

But it is just setted in a part of the screen.

Also could not make the navigation bar translucent

UINavigationController.navigationBar.setBackgroundImage(UIImage(), forBarMetrics: UIBarMetrics.Default)
UINavigationController.navigationBar.shadowImage = UIImage()
UINavigationController.view.backgroundColor      = UIColor.clearColor()
UINavigationController.navigationBar.translucent = true

The above code is tested in my whole app, but cannot make it work for this component

thanks in advance