pnmrotate

Rotate a PNM image. More information: https://netpbm.sourceforge.net/doc/pnmrotate.html.

• Rotate a PNM image by some angle (measured in degrees, counter-clockwise):

pnmrotate angle path/to/input.pnm > path/to/output.pnm

• Specify the background color exposed by rotating the input image:

pnmrotate -background color angle path/to/input.pnm > path/to/output.pnm

• Disable anti-aliasing, improving performance but decreasing quality:

pnmrotate -noantialias angle path/to/input.pnm > path/to/output.pnm