How to make a screenshot of all the content of a Scrollview?

Question

I want to create a screenshot of a UIScrollView which should contain the whole content of the scroll view, even that content, which is currently not visible to the user. For that I tried the following two methods:

func snapShot(view:UIView) -> UIImage {
    UIGraphicsBeginImageContextWithOptions(view.bounds.size, true, 0);

    view.drawViewHierarchyInRect(view.bounds, afterScreenUpdates: true);

    let image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return image;
}

func snapShotScrollView(scrollView:UIScrollView) -> UIImage {
    let bounds = scrollView.bounds;

    scrollView.bounds.size = scrollView.contentSize;

    let image = snapShot(scrollView);

    scrollView.bounds = bounds;

    return image;
}

But the resulting image is still just showing those view elements inside the scroll view which are currently visible to the user. But I want to see all views.

How can I do that?

EDIT

I also tried:

func snapshot() -> UIImage? {
    var image: UIImage?

    UIGraphicsBeginImageContext(scrollView.contentSize)

    let savedContentOffset = scrollView.contentOffset
    let savedFrame = scrollView.frame;

    scrollView.contentOffset = CGPoint.zero;
    scrollView.frame = CGRect(x: 0, y: 0, width: scrollView.contentSize.width, height: scrollView.contentSize.height);

    scrollView.layer.render(in: UIGraphicsGetCurrentContext()!)
    image = UIGraphicsGetImageFromCurrentImageContext();

    scrollView.contentOffset = savedContentOffset;
    scrollView.frame = savedFrame;

    UIGraphicsEndImageContext();

    return image
}

Edit 2

My UIScrollView is placed inside a UIView and does contain a UIStackView. The View is designed as a popover view so that it looks like a dialogue is popping up. The code sample from my first edit is working in a blank UIViewController with only one UIScrollView but not in the mentioned constellation.

Answer 1

To Swift from this answer, adding a test ViewController:

class ScreenShotTestViewController: UIViewController {

    var scrollView: UIScrollView!

    override func viewDidLoad() {
        super.viewDidLoad()
        scrollView = UIScrollView(frame: CGRect(origin: CGPoint.zero, size: view.frame.size))
        scrollView.contentSize = CGSize(width: view.frame.size.width, height: view.frame.size.height * 2)
        scrollView.backgroundColor = UIColor.yellow
        view.addSubview(scrollView)

        let label = UILabel(frame: CGRect(x: 0.0, y: view.frame.size.height * 1.5, width: view.frame.size.width, height: 44.0))
        label.text = "Hello World!"
        scrollView.addSubview(label)

        let screenShot = snapshot()
    }

    func snapshot() -> UIImage?
    {      
        UIGraphicsBeginImageContext(scrollView.contentSize)

        let savedContentOffset = scrollView.contentOffset
        let savedFrame = scrollView.frame

        scrollView.contentOffset = CGPoint.zero
        scrollView.frame = CGRect(x: 0, y: 0, width: scrollView.contentSize.width, height: scrollView.contentSize.height)

        scrollView.layer.render(in: UIGraphicsGetCurrentContext()!)
        let image = UIGraphicsGetImageFromCurrentImageContext()

        scrollView.contentOffset = savedContentOffset
        scrollView.frame = savedFrame

        UIGraphicsEndImageContext()

        return image
    }
}

Results in an image of the complete content, including subviews: