CODEWITHSUNDEEP
iosswiftuiscrollviewcagradientlayer
Emre Önder
Emre Önder

Reputation: 2537

Remove ScrollView Gradient Fade on bottom when reached bottom

I have an UIScrollView which has a fade-out bottom gradient layer (like in below screeshot). I want to remove it when reached to bottom of UIScrollView. I found below posts but nothing worked for me.

https://stablekernel.com/how-to-fade-out-content-using-gradients-in-ios/

Fade edges of UITableView

let gradient = CAGradientLayer()
gradient.frame = myTextView.bounds
gradient.colors = [UIColor.clear.cgColor, UIColor.black.cgColor, UIColor.black.cgColor, UIColor.clear.cgColor]
gradient.locations = [0, 0.0, 0.7, 1]
myTextView.layer.mask = gradient

override func layoutSubviews() {
    gradient.frame = kvkkTextView.bounds
}

When I try to change the frame of gradient in 

private func updateGradientFrame() {
gradient.frame = CGRect(
    x: 0,
    y: kvkkTextView.contentOffset.y,
    width: kvkkTextView.bounds.width,
    height: kvkkTextView.bounds.height
)
}

It causes a weird bug. When I scroll it, texts seen on screen slowly (When I fastly scroll it, screen seen blank and then text appears).

screenshot

Upvotes: 2

Views: 1638

Answers (1)

Sateesh Yemireddi
Sateesh Yemireddi

Reputation: 4409

Try this

func scrollViewDidScroll(_ scrollView: UIScrollView) {

    updateGradientFrame()

    //On the scroll view content is over means there is no content anymore then hide the mask
    if scrollView.contentOffset.y >= scrollView.contentSize.height - scrollView.bounds.height {

        label.layer.mask = nil
    } else {

        //Else show the mask of UILabel
        label.layer.mask = gradient
    }
}

Update:

private func updateGradientFrame() {
    gradient.frame = CGRect(
        x: 0,
        y: scrollView.contentOffset.y,
        width: scrollView.bounds.width,
        height: scrollView.bounds.height
        )
}

GitHub Url: https://github.com/sateeshyegireddi/GradientScrollViewDemo

Upvotes: 2

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