pnmcrop
Crop PNM images.
TLDR
Remove white borders on a PNM image
$ pnmcrop -white [path/to/image.pnm] > [path/to/output.pnm]
Remove borders of the specified color that are on the top and left side of the image
$ pnmcrop -bg-color [color] -top -left [path/to/image.pnm] > [path/to/output.pnm]
Determine the color of the borders to be removed by the color of the pixel in the specified corner
$ pnmcrop -bg-corner [topleft|topright|bottomleft|bottomright] [path/to/image.pnm] > [path/to/output.pnm]
Leave a border with a width of n pixels. Additionally, specify the behaviour if the image is entirely made out of background
$ pnmcrop -margins [n] -blank-image [pass|minimize|maxcrop] [path/to/image.pnm] > [path/to/output.pnm]
