Scale pages to fit the printable area.
void pdfSetShrinkToPrintable(PDFViewerHandle viewer, BOOL shrink)
This function tells XpdfViewer to shrink all printed pages to fit the printable region of the paper, which is generally smaller than the full paper size. This defaults to false (i.e., print to the full sheet of paper).
pdfSetShrinkToPrintable(viewer, TRUE);