THPDFViewerPreference Type

vpHideToolbar, vpHideMenubar and vpHideWindowUI hide viewer interface elements
vpFitWindow resizes the document window to the first displayed page
vpCenterWindow centres the document window on the screen
vpDisplayDocTitle shows the document Title entry in the window title
vpDirection sets the predominant reading order for text
vpNonFullScreenPageMode selects the page mode used after exiting full-screen mode
vpPrintScaling selects the print scaling option
vpDuplex selects the duplex printing option
vpPickTrayByPDFSize picks the output tray by PDF page size
vpNumCopies sets the number of print copies
vpPrintArea and vpPrintClip select the page boundaries for printing
vpViewArea and vpViewClip select the page boundaries for on-screen viewing

THPDFViewerPreferences is a set of these flags