struct MyIntroDataSource: IntroDataSource {
    
    let numberOfPages = 3
    
    // Set to true, if you want to fade out the last page color into black.
    let fadeOutLastPage: Bool = false
    
    func viewController(at index: Int) -> IntroPageViewController? {
        switch index {
        case 0:
            return DefaultIntroPageViewController(
                index: index,
                hue: 30/360,
                title: "First page",
                subtitle: "This is the first page.",
                image: UIImage(named: "first")!
            )
        case 1:
            return DefaultIntroPageViewController(
                index: index,
                hue: 60/360,
                title: "Second page",
                subtitle: "This is the second page.",
                image: UIImage(named: "second")!
            )
        case 2:
            return DefaultIntroPageViewController(
                index: index,
                hue: 90/360,
                title: "Third page",
                subtitle: "This is the third page.",
                image: UIImage(named: "third")!
            )
        default:
            return nil
        }
    }
}

let viewController = IntroViewController(dataSource: dataSource)

public protocol IntroPage: AnyObject {
    
    // ...
    
    /// The color hue between 0 & 1 for the HSV color.
    var hue: CGFloat { get }
}

let viewController = IntroViewController(
  dataSource: dataSource,
  saturation: 0.85, 
  brightness: 0.9
)

introViewController.nextPage() // navigate forward
introViewController.previousPage() // navigate backwards