Hello,
I don’t believe there is a recommended pattern or a single function in WebViewer to accomplish this. One option you do you have is to switch to single page viewing mode and adjust the zoom level based on the size of the next page.
Otherwise, you will have to perform some sort of document processing before you load and view in WebViewer. This can be done within WebViewer, but I would recommend using our PDFNet SDK instead to process the document on upload. You would probably look for a function similar to this one in PDFNet: PDFTron WebViewer Class: Page.