Starts a new page.
pdf_documentThe document handle, returned by cpdf_open().
page_numberThe page number
orientation0 for portrait and 1 for landscape
heightThe page height
widthThe page width
unitThe unit for the coordinate system. The value should be the number of postscript points per unit. Since one inch is equal to 72 points, a value of 72 would set the unit to one inch. The default is also 72.