 			layout.itemSize = computeItemSize()
 			layout.invalidateLayout()
 //			collectionView.collectionViewLayout.invalidateLayout()
+			
+			updateLabel()
 		}
 	}
 	

//		collectionView.setNeedsLayout()
//		collectionView.reloadData()
//		layout.invalidateLayout()
	}
	
	override func viewWillAppear(animated: Bool) {

		super.loadView()
		view.backgroundColor = UIColor.lightGrayColor()
		view.addSubview(collectionView)
		view.addSubview(titleLabel)
		view.addSubview(valueLabel)
	}
	
	lazy var titleLabel: UILabel = {
		let instance = UILabel()
		instance.text = "Value"
		instance.numberOfLines = 0
		instance.textAlignment = .Left
		instance.font = UIFont.boldSystemFontOfSize(18)
		return instance
	}()
	
	lazy var valueLabel: UILabel = {
		let instance = UILabel()
		instance.text = "-"
		instance.numberOfLines = 0
		instance.textAlignment = .Right
		instance.font = UIFont.systemFontOfSize(20)
		return instance
	}()

	func updateLabel() {
		let x: CGFloat = collectionView.contentOffset.x
		let s = String(format: "%.3f", x)
		valueLabel.text = s
	}
	
	lazy var pinchGestureRecognizer: UIPinchGestureRecognizer = {
