 class ViewController: UIViewController {
     
     @IBOutlet weak var collectionView: UICollectionView!
+    
+    fileprivate var cellSize: CGSize?
     
     override func viewDidLoad() {
         super.viewDidLoad()

        
        collectionView.delegate = self
        collectionView.dataSource = self
    }
    
    fileprivate func setupScrollView(){
        
        collectionView.contentInset = UIEdgeInsets(top: 20, left: 0, bottom: 0, right: 0)
    }
}

        
        let width = UIScreen.main.bounds.width - 60 // 30 margin aan beide kanten
        
        let height = collectionView.frame.height - 120 // 70 margin hoogte
        
        cellSize = CGSize(width: width, height: height)
        
        return cellSize!
    }
}

extension ViewController: UIScrollViewDelegate {
    
    
}

extension ViewController {
