Rotate in pdfPrintW

Use the command

COMPDF_SelectPrinter

The function returns the new index of the printer.

to pass the one of the following:

1. name of the printer
2. the start of the name
3. any part of the name

This list of printer names is processed in this order to find the match.

How do I configure, through code, the default printer in the viewer?

You cannot. The rotation is just for the display in the viewer.

How do I rotate with the command pdfPrintW?