How do I center a PDFSelection within the overall View?

Question

I'm trying to use PDFKit with Swift in iOS 11. I have a PDFView and a PDFSelection that I would like to scroll to, zoom in to, and center within the overall view. I'm able to scroll to the PDFView's currentSelection with the function scrollSelectionToVisible(_ sender: Any?), but the selection always appear in the upper left of the screen.

How can I reposition the page to make the selection be at the center?

I know a PDFSelection has a bounds(for: PDFPage) function that returns a CGRect, in page space. But I don't know what to do with it beyond that.

What I currently see with after pdfView.scrollSelectionToVisible() (currentSelection in green upper left):

What I'd like to see (currentSelection in center of view):

This:

pdfView.currentSelection = selection
pdfView.scrollSelectionToVisible(nil)

And this:

pdfView.currentSelection = selection
let pdfPage = pdfView.document!.page(at: 0)!
let cgRect = pdfView.currentSelection!.bounds(for: pdfPage)
pdfView.go(to: cgRect, on: pdfPage)

are producing the same effect (the effect in the first image).

Answer 1

After you create the PDFviewer center the view like this

let pdfView = PDFView(frame: viewFA.view.bounds) 
pdfView.center.y = viewFA.view.center.y - 100