pnmpad
Add borders to a PNM image.
TLDR
Add borders of the specified sizes to the image
$ pnmpad -left [100] -right [150] -top [123] -bottom [456] [path/to/image.pnm] > [path/to/output.pnm]
Pad the image to the specified size
$ pnmpad -width [1000] -height [500] [path/to/image.pnm] > [path/to/output.pnm]
Pad the width of the image to the specified size, controlling the ratio between right and left padding
$ pnmpad -width [1000] -halign [0.7] [path/to/image.pnm] > [path/to/output.pnm]
Pad the width of the image using the specified color
$ pnmpad -width [1000] -color [red] [path/to/image.pnm] > [path/to/output.pnm]
