Generate resized icons for mastodon

gen_mastodon_icons.sh

#!/bin/bash
if [ -z $(which convert) ];then
  echo "Missing ImageMagick. Aborted."
  exit 1
fi
TARGET_IMAGE=${1}
if [ -z "${TARGET_IMAGE}" ] || [ ! -f "${TARGET_IMAGE}" ];then
  echo "Missing image. Aborted."
  exit 2
fi
GEN_DIR=mastodon-icons-`date '+%Y%m%d'`
PREFIX=("android-chrome" "apple-touch-icon" "favicon")
G_SIZES=("36" "48" "72" "96" "144" "192" "256" "384" "512")
A_SIZES=("1024" "180" "167" "152" "144" "120" "114" "76" "72" "60" "57")
W_SIZES=("16" "32" "48")
resize_square() {
INPUTFILE=${1}
TOSIZE=${2:-"512"}
PREFIX=${3:-"favicon"}
OUTPUTFILE=${GEN_DIR}/${PREFIX}-${TOSIZE}x${TOSIZE}.png
convert $INPUTFILE -resize ${TOSIZE}x${TOSIZE}! $OUTPUTFILE
}
# MKDIR
mkdir -p ${GEN_DIR}

# for android
for el in "${G_SIZES[@]}"; do
   resize_square ${TARGET_IMAGE} ${el} ${PREFIX[0]}
done
# for apple
for el in "${A_SIZES[@]}"; do
   resize_square ${TARGET_IMAGE} ${el} ${PREFIX[1]}
done
# for favicon
for el in "${W_SIZES[@]}"; do
   resize_square ${TARGET_IMAGE} ${el} ${PREFIX[2]}
done