iOS Parallax Scrolling effect (like in Yahoo News Digest app)

Question

I would like to know how to implement parallax scrolling similar to Yahoo News Digest app. In which when user scroll horizontally background image scrolls in a different speed w

Answer 1

Swift 3

Here's how I got a parallax effect to work in Swift 3 for a vertical scroll in a tvOS app.

In ViewDidLoad():

    parallaxScrollView.delegate = self
    detailScrollView.delegate = self

And following:

override func viewDidLayoutSubviews() {
        self.detailScrollView!.contentSize = CGSize(width: 1920, height: 2700)
        self.parallaxScrollView?.contentSize = CGSize(width: 1920, height: 3000)
    }


//// THE SCROLL VIEW

func scrollViewDidScroll(_ scrollView: UIScrollView) {

    // Parallax effect
    let detailMaxOffset = self.detailScrollView.contentSize.height - self.detailScrollView.frame.height;
    let percentage = self.detailScrollView.contentOffset.y / detailMaxOffset
    let parallaxMaxOffset = self.parallaxScrollView.contentSize.height - self.parallaxScrollView.frame.height;
    let parallaxOffset = CGPoint(x:0,y:(percentage * parallaxMaxOffset))
    self.parallaxScrollView.setContentOffset((parallaxOffset), animated: false)

}