pnmpad
Add borders to a PNM image. tldr-pages
On several platforms
Several platforms
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.pnmIdentifyPad the image to the specified size
pnmpad -width 1000 -height 500 path/to/image.pnm >path/to/output.pnmIdentifyPad 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.pnmIdentifyPad the width of the image using the specified color
pnmpad -width 1000 -color red path/to/image.pnm >path/to/output.pnmIdentify