App working in the background

(iOS12 case)When our application is working in the background the application make to use api called Document_getPageWidth. in this case Document_getPageWidth api is not return.

(iOS11 case)In this same case that working application in the background use called vGetPos api is return the page number that was previously used

Hi,
Probably this situation was created because of some methods (look draw method in PDFView.m) will not called when app is in background so it work differently between running the app foreground.