to define a rectangular region within the coordinate space of an output pane or printer port. Within
the region is mapped onto the printable area of the page. If the specified rectangle does not have the same aspect ratio as the printable area of the page, then non-isotropic scaling will occur.
Any number of calls to
can occur during the printing of a page; for example, it is sometimes convenient to use a different page transform from that used to print the main body of the page when printing headers and footers.