Returns the vertical shift of the document page on the poster, pixels.
property OffYPix: Extended;
Posters are printed if PrintMode = srvpPoster.
The shift is nonzero if
•the document page is not scaled to the full poster size (ScaleImage=False) and
•the page is printed at the center of the poster (Center =True) and
•the page height (RealHeight) is smaller than the poster height (PageHeightPix).
OffXPix and OffYPix