#! /bin/bash
# This script tests: ppmchange
# Also requires: pgmtopbm pnminvert ppmtopgm


ppmchange black white white black testgrid.pbm | \
pnminvert | ppmtopgm | \
pgmtopbm -th -val=0.5 | cksum

ppmchange  black white white black testgrid.pbm | \
ppmchange  black white white black | \
ppmtopgm | pgmtopbm -th -val=0.5 | cksum