UiScrollview with nested image looks weird - uiscrollview

Question

I have a UIScrollView inside a UIViewController (subclassed by ImageViewController). The ViewController itself is part of a NavigationController's stack. Now, apart from having a navigation bar, I want the ScrollView to take all of the available room on the screen. The UIImageView inside the scrollview should then fill the available room of the scroll view. You can see the current state at the bottom of this posting.
class ImageViewController: UIViewController, UIScrollViewDelegate {
#IBOutlet weak var scrollView: UIScrollView!
var imageView: UIImageView?
var image: UIImage?
override func viewDidLoad() {
super.viewDidLoad()
scrollView.delegate = self
if let image = image {
imageView = UIImageView(image: image)
if let imageView = imageView {
imageView.frame = CGRect(origin: CGPoint(x: 0, y: 0), size: image.size)
scrollView.addSubview(imageView)
scrollView.contentSize = image.size
let scaleHeight = scrollView.frame.size.height / scrollView.contentSize.height
let scaleWidth = scrollView.frame.size.width / scrollView.contentSize.width
let minimumScale:CGFloat = min(scaleHeight, scaleWidth)
let maximumScale:CGFloat = max(scaleHeight, scaleWidth)
scrollView.minimumZoomScale = minimumScale
scrollView.maximumZoomScale = maximumScale
scrollView.zoomScale = maximumScale
}
}
}
func viewForZoomingInScrollView(scrollView: UIScrollView) -> UIView? {
return imageView
}
}
The code leaves me with unnecessary borders (left, right, top). How do I get rid of them?
EDIT: With #Bxtr's suggestion and another stackoverflow thread I was able to remove the borders left and right to the scroll view. After some more digging I found out that by deactivating Adjust Scroll View Insets, the image inside the scroll view can be correctly vertically positioned. Still, I do not get the reason for the vertical misplacement in the first place...

Answer 1

Have you checked the margin/padding values, because it kinda looks so (same size on left and right border). If it is not the case, could you please also post your xml file of the activity so we can have every part of the puzzle to help you ?

Answer 2

scrollView.contentSize = image.size;
you have to tweek this line. You are explicitly setting scroll view content size to the image size. You have to set content size to fit the Width of Screen.

Answer 3

You can use a UIView in UIScrollView, and that UIView contains UIImage.
You need to set constraints properly.

Answer 4

After some more digging I found out that by deactivating Adjust Scroll
View Insets, the image inside the scroll view can be correctly
vertically positioned. Still, I do not get the reason for the vertical
misplacement in the first place...
The reason is that the view controller's automaticallyAdjustsScrollViewInsets property is by default YES, the following is from apple documentation:
automaticallyAdjustsScrollViewInsets
A Boolean value that indicates
whether the view controller should automatically adjust its scroll
view insets.
Default value is YES, which allows the view controller to adjust its
scroll view insets in response to the screen areas consumed by the
status bar, navigation bar, and toolbar or tab bar. Set to NO if you
want to manage scroll view inset adjustments yourself, such as when
there is more than one scroll view in the view hierarchy.
Besides setting automaticallyAdjustsScrollViewInsets = No, you can pin the scrollView to the topLayoutGuide (instead of to the top of the viewController's view) when using autoLayout.