pnmhistmap
Draw a histogram of a PNM image.
TLDR
Draw a histogram of a PNM image
$ pnmhistmap [path/to/input.pnm] > [path/to/output.pnm]
Draw the histogram as dots instead of bars
$ pnmhistmap -dots [path/to/input.pnm] > [path/to/output.pnm]
Specify the range of intensity values to include
$ pnmhistmap -lval [minval] -rval [maxval] [path/to/input.pnm] > [path/to/output.pnm]
