ppmchange

Change all pixels of one color in a PPM image to another color. More information: https://netpbm.sourceforge.net/doc/ppmchange.html.

• Exchange the first color in each oldcolor - newcolor pair with the second color:

ppmchange {{oldcolor1 newcolor1 oldcolor2 newcolor2 ...}} {{path/to/input.ppm}} > {{path/to/output.ppm}}

• Specify how similar colors must be in order to be considered the same:

ppmchange -closeness {{percentage}} {{oldcolor1 newcolor1 oldcolor2 newcolor2 ...}} {{path/to/input.ppm}} > {{path/to/output.ppm}}

• Replace all pixels not specified in the arguments by a color:

ppmchange -remainder {{color}} {{oldcolor1 newcolor1 oldcolor2 newcolor2 ...}} {{path/to/input.ppm}} > {{path/to/output.ppm}}