#!/bin/sh
# env
# Written in 2019 by Lucas
# CC0 1.0 Universal/Public domain - No rights reserved
#
# To the extent possible under law, the author(s) have dedicated all
# copyright and related and neighboring rights to this software to the
# public domain worldwide. This software is distributed without any
# warranty. You should have received a copy of the CC0 Public Domain
# Dedication along with this software. If not, see
# <http://creativecommons.org/publicdomain/zero/1.0/>.

: ${CANVAS_BGCOLOR:="#0d0a00"}
: ${CANVAS_HEIGHT:=768}
: ${CANVAS_WIDTH:=1366}
: ${IMAGE_HEIGHT:=768}
: ${IMAGE_WIDTH:=1080}

pos_x=$((($CANVAS_WIDTH - $IMAGE_WIDTH) / 2))
pos_y=$((($CANVAS_HEIGHT - $IMAGE_HEIGHT) / 2))

if ! tmpfile=$(mktemp -t bg.XXXXXXXXXX); then
	printf "%s: Can't create temporary file.\n" "${0##*/}" >&2
	exit 1
fi

trap 'rm -f "$tmpfile"' EXIT INT QUIT TERM

pngtopam -alphapam cyberia-cafe-club.png \
    | pamscale -width="$IMAGE_WIDTH" -height="$IMAGE_HEIGHT" \
    >"$tmpfile"
ppmmake "$CANVAS_BGCOLOR" "$CANVAS_WIDTH" "$CANVAS_HEIGHT" \
    | pamcomp -xoff="$pos_x" -yoff="$pos_y" "$tmpfile" \
    | pamtopng >cyberia-cafe-club-bg.png