UIPageViewController: how to have "negative" spacing between view controllers (with scroll-transition style)

Question

I have to implement a view controller (on iPhone, portrait only, full screen view) where the upper part of the view must have an horinzontal, paged scrolling behavior, potentially infinite.

I already used for similar purposes UIPageViewControllers, to take advantage of the datasource and delegate protocols, which are very helpul for manage memory and other stuff (keeping only 3 view controllers in memory, providing delegates to handle actions exactly when a transition is done and so on): so I think that in this case too this component is the best choice.

But here comes my problem. In the view I'm realizing, I have to let the user understand that he can swipe left and right to move to another view: a page control is not a good choice, since the scroll could be potentially infinite, so I would like to let a small portion of the views of the left and right view controllers to be visible.
Something like that:

link to the image (sorry I cannot include images in my posts yet)

Up to now I have not been able to figure out how to realize this. In the options during initialization, UIPageViewControllerOptionSpineLocationKey can be specified to set (from documentation) "Space between pages, in points": but this seems to work only with positive value, so that the space increases, while it ignores negative values that could reduce the space.

I hope there might be a solution using page view controllers, since at the same time I need to refresh a table view in the lower part of the screen when a transition is complete, and the delegate method of page controllers is ideal for this aim. Maybe a collection view can be an alternate solution, but it is more complicated and I'm not sure how to obtain a behavior like the one I described to refresh the table view.

If needed I can attach some code and a screenshot of the prototype

Answer 1

Ok, I understand that this is not possible and why it is. The datasource methods load, when needed, the view controllers that are before and after the current one. Making these view controllers' views always visible, as I desired, will require that the datasource loads more than one view controllers after (or before, depends on the direction of scrolling) the current one, to be ready for the pan actions (potentially, before the animation is ended by the user lifting up its finger, two view controllers "after" or "before" could become visible it my desired configuration), and this is not intended by UIPageViewController on iPhone, especially in portrait mode.

So actually, the only way to achieve that more than one view is visible in an horizontal-scrolling component at any time, is to implement a UIScrollview with horizontal paging and calculate the contentSize and other sizes accordingly.