The properties return a page height of document on the screen.
property PageHeightPix: Integer;
property PageHeight100Pix: Integer;
PageHeightPix returns the page height converted to screen pixels and scaled according to ViewProperty.ZoomPercent (i.e. a page height as it can be seen in the control window).
PageHeight100Pix returns the page height converted to screen pixels in ZoomPercent=100. The same value measured in UnitsProgram is returned in ViewProperty.PageHeight.
The page height is defined in PageProperty.PageHeight.