kyle-Snippet: Colorize PNG of text and quantize

textImageProcessor.sh

#!/bin/bash

set -o pipefail -o errexit -o noglob -o nounset

function usage() {
    cat <<EOUSAGE
Usage: textImageProcessor [OPTIONS] ...
Colorizes and/or optimizes rasterized text.
OPTION      DESCRIPTION
==========  ==================================================================
-c          Hex color for colorizing (must include '#')
-h          This text
EOUSAGE
}

function printErr() {
    echo -e "$1" >&2
}

function includeHash() {
    printErr "Make sure to include a hash at the beginning of your Hex color;"
    printErr "e.g., '#000'"
    exit 1
}

c=''

while getopts ":c:h" o; do
    case "${o}" in
        c)
            c=${OPTARG}
            [[ $c =~ ^\# ]] || includeHash
            ;;
        h)
            usage
            exit 0
            ;;
        *)
            usage >&2
            exit 1
            ;;
    esac
done

shift $((OPTIND-1))

if [ $# -ne 0 ]; then
   printErr "No args are accepted \n"
   usage >&2
   exit 1
fi

if [ -z "${c}" ]; then
        pngquant --speed 1 --nofs 6 -
else
        convert - \( -clone 0 -fill "$c" -draw 'color 0,0 reset' \) -compose Atop -composite - |
        pngquant --speed 1 --nofs 6 -
fi

exit 0