pnmshear
Shear a PNM image.
TLDR
Shear a PNM image by the specified angle
$ pnmshear [angle] [path/to/input.pnm] > [path/to/output.pnm]
Specify the color of the background in the sheared image
$ pnmshear -background [blue] [angle] [path/to/input.pnm] > [path/to/output.pnm]
Do not perform anti-aliasing
$ pnmshear -noantialias [angle] [path/to/input.pnm] > [path/to/output.pnm]