pnmtoddif

Convert a PNM image to a DDIF image file. More information: https://netpbm.sourceforge.net/doc/pnmtoddif.html.

pnmtoddif path/to/image.pnm > path/to/image.ddif

pnmtoddif -resolution horizontal_dpi vertical_dpi path/to/image.pnm > path/to/image.ddif