Half the Scrollview

ViewController.swift

class ViewController: UIViewController, UIScrollViewDelegate {
    @IBOutlet var scrollView: UIScrollView?
    var elementSize = CGSizeZero
    var grid = (6, 8)
    var container: UIView?

    override func viewDidLoad() {
        scrollView?.delegate = self

        elementSize = UIImage(named: "chop")!.size
        container = UIView()
        container?.frame = CGRect(x: 0,
                                  y: 0,
                                  width: CGFloat(grid.0) * elementSize.width,
                                  height: CGFloat(grid.1) * elementSize.height)

        for x in 0..<grid.0 {
            for y in 0..<grid.1 {
                let filename = (x + y) % 2 == 0 ? "chop" : "rockies"
                let img = UIImage(named: filename)
                let imgv = UIImageView(image: img)
                let origin = CGPoint(x: CGFloat(x) * elementSize.width,
                                     y: CGFloat(y) * elementSize.height)
                imgv.frame = CGRect(origin: origin, size: elementSize)
                container?.addSubview(imgv)
            }
        }
        scrollView?.addSubview(container!)
        scrollView?.contentSize = container!.bounds.size

        scrollView?.minimumZoomScale = 0.1
        scrollView?.maximumZoomScale = 6.0
        scrollView?.indicatorStyle = UIScrollViewIndicatorStyle.White
    }

    func viewForZoomingInScrollView(scrollView: UIScrollView) -> UIView? {
        return container
    }
}