#!/bin/bash
set -eu

if [ "$#" -ne 2 ]; then
    echo
    echo "Syntax: $0 [IMAGE.png] [NAME]"
    echo
    echo 'IMAGE.png -> screenshot-NAME.png + screenshot-NAME-small.png'
    echo
    exit 1
fi

set -v

IMAGE_FILE="$1"
NAME="$2"

cat "$IMAGE_FILE" \
| pngtopnm \
| pnmtopng -compression 9 \
> "screenshot-$NAME.png"

cat "screenshot-$NAME.png" \
| pngtopnm \
| pnmscale -ysize 128 \
> "screenshot-$NAME-small.pnm"

pnmquant 256 "screenshot-$NAME-small.pnm" \
| pnmtopng -compression 9 \
> "screenshot-$NAME-small.png"

rm -f "screenshot-$NAME-small.pnm"