70 lines
1.3 KiB
Bash
70 lines
1.3 KiB
Bash
#!/bin/sh
|
|
# imgresize
|
|
# Written in 2019-2020 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/>.
|
|
|
|
usage()
|
|
{
|
|
cat - <<. >&2
|
|
Usage:
|
|
${0##*/} size in-file out-file
|
|
|
|
"size" is WxH or Wx or xH.
|
|
.
|
|
exit 1
|
|
}
|
|
|
|
err()
|
|
{
|
|
printf "%s: %s\n" "${0##*/}" "$*" >&2
|
|
exit 1
|
|
}
|
|
|
|
check_dimension_format()
|
|
{
|
|
printf "%s\n" "$1" | grep -q "^[0-9]*x[0-9]*\$" && [ "$1" != "x" ]
|
|
}
|
|
|
|
[ $# -eq 3 ] && check_dimension_format "$1" || usage
|
|
[ -n "$2" ] || err "input file name can't be empty"
|
|
[ -n "$3" ] || err "output file name can't be empty"
|
|
|
|
size=$1
|
|
w=${size%x*}
|
|
h=${size#*x}
|
|
infile=$2
|
|
outfile=$3
|
|
|
|
inprog=
|
|
case $infile in
|
|
*.jpg | *.jpeg)
|
|
inprog=jpegtopnm
|
|
;;
|
|
*.png) inprog=pngtopam
|
|
;;
|
|
*) err "unknown input format"
|
|
;;
|
|
esac
|
|
|
|
outprog=
|
|
case $outfile in
|
|
*.jpg | *.jpeg)
|
|
outprog=pnmtojpeg
|
|
;;
|
|
*.png) outprog=pamtopng
|
|
;;
|
|
*) err "unknown output format"
|
|
;;
|
|
esac
|
|
|
|
$inprog <"$infile" |
|
|
pamscale ${w:+-width "$w"} ${h:+-height "$h"} |
|
|
$outprog >"$outfile"
|