UICollectionView horizontal paging with 3 items

Question

I need to show 3 items in a UICollectionView, with paging enabled like this

Answer 1

Mine solution to horizontal collection view paging

func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
    if scrollView == collectionView { collectionView.scrollToPage() }
}

func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
    if scrollView == collectionView { if !decelerate { collectionView.scrollToPage() } }
}

And small extension to collectionView

public func scrollToPage() {
        var currentCellOffset = contentOffset
        currentCellOffset.x += width / 2
        var path = indexPathForItem(at: currentCellOffset)
        if path.isNil {
            currentCellOffset.x += 15
            path = indexPathForItem(at: currentCellOffset)
        }
        if path != nil {
            logInfo("Scrolling to page \(path!)")
            scrollToItem(at: path!, at: .centeredHorizontally, animated: true)
        }
    }