pdfPrintSetRotate

Set the page rotation.
void pdfPrintSetRotate(PDFHandle pdf, int angle)
This function sets the page rotation. Allowed rotation values are 0, 90, 180, and 270 degrees.

pdfPrintResetParams resets this to its default value, which is to print portrait-mode pages with a rotation of 0 and landscape pages with a rotation of 90.

C:
pdfPrintSetRotate(pdf, 180);
pdfPrintResetParams