CAGradient Background Layer

[funkenstrahlen]

I would like the NavigationBar to use a gradient background layer when it is in the transparent state. Some images have very light colors which makes the navigation bar content elements nearly invisible.

What is the best way to do that?

[funkenstrahlen]

Maybe something like this could work: http://zappdesigntemplates.com/custom-gradient-navigation-bar-in-ios-using-swift/