Fix UIView elements to avoid changing dimensions in "scrollViewDidScroll" function

Question

I've created a UIScrollView to show it in another UIViewController with a header. In my scrollViewDidScroll(), I have some code that decreases header's height. But when it performs, all of the elements (Label) in header view changes. Is there any way to keep their dimensions fix?

my scrollViewDidScroll() function is here:

func scrollViewDidScroll(_ scrollView: UIScrollView) {

        var labelAlpha = 4 * scrollView.contentOffset.y / scrollView.frame.height
        labelAlpha = max(0, labelAlpha)
        labelAlpha = min(1, labelAlpha)
        let parent = self.parent as? ScrollParentViewController
        var viewScale = 1.0 - 4 * scrollView.contentOffset.y / scrollView.frame.height
        viewScale = max(0.5, viewScale)
        parent?.redView.transform = CGAffineTransform(scaleX: 1, y: viewScale)
        parent?.redView.frame.origin.y = 0
        parent?.whiteLabel.alpha = labelAlpha

    }

Answer 1

Finally found my answer. I'll post it for you to use if you need. For this case we shouldn't use transform. We can work with view.frame.size.height. You should save view's height size in a variable at the first because its value will change. so add it to your HeaderViewController (In my case its name is ScrollParentViewController):

var height: CGFloat!
override func viewDidLoad() {
    super.viewDidLoad()
    height = redView.frame.height
}

then you can use this variable in your scrollViewDidScroll():

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    var viewScale = 1.0 - 4 * scrollView.contentOffset.y / scrollView.frame.height
    viewScale = max(0.5, viewScale)
    let parent = self.parent as? ScrollParentViewController
    parent?.redView.frame.size.height = (parent?.height)! * viewScale
}

thanks for helps.