dots-of-war/files/scripts/resizeGif.sh

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#!/bin/sh
calc_percentage() {
echo "$(($(("$1" / 100)) * "$2"))"
}
help() {
cat << EOT
Usage: resizeGif.sh <input-file> [OPTIONS]
you can provide --percentage or --coarse-in to decide how to resize the gif
Options:
-p --percentage <number> size percentage to resize the image to
-c --coarse-in <x_res>x<y_res> maximum resolution to box the output image in
-o --out <filename> name of the output file
EOT
}
if [ -z "$1" ]; then
help
exit 1
fi
IN_FILE="$1"
shift
while [ -n "$1" ]; do
case "$1" in
-p|--percentage)
shift
PERCENTAGE="$1"
;;
-c|--coarse-in)
shift
COARSE_IN="$1"
;;
-o|--out)
shift
OUT_FILE="$1"
;;
esac
shift
done
[ -n "$PERCENTAGE" ] && [ -n "$COARSE_IN" ] && {
echo "You may only provide percentage OR coarse-in"
exit 1
}
base_resolution=$(identify "$IN_FILE" | awk 'NR==1{print $3}')
x_res="$(echo "$base_resolution" | sed 's/\(.*\)x\(.*\)/\1/g')"
y_res="$(echo "$base_resolution" | sed 's/\(.*\)x\(.*\)/\2/g')"
if [ -n "$PERCENTAGE" ]; then
x_scaled="$(calc_percentage "$x_res" "$PERCENTAGE")"
y_scaled="$(calc_percentage "$y_res" "$PERCENTAGE")"
elif [ -n "$COARSE_IN" ]; then
arg_x="$(echo "$COARSE_IN" | sed 's/\(.*\)x\(.*\)/\1/g')"
arg_y="$(echo "$COARSE_IN" | sed 's/\(.*\)x\(.*\)/\2/g')"
x_fact="$(( $((arg_x * 100)) / x_res))"
y_fact="$(( $((arg_y * 100)) / y_res))"
if [ "$x_fact" -lt "$y_fact" ]; then
lower_fact="$x_fact"
else
lower_fact="$y_fact"
fi
x_scaled="$(calc_percentage "$x_res" "$lower_fact")"
y_scaled="$(calc_percentage "$y_res" "$lower_fact")"
else
echo "You need to give --percentage or --coarse-in."
exit 1
fi
if [ -z "$OUT_FILE" ]; then
OUT_FILE="smaller_${IN_FILE}"
fi
echo "resizing to ${x_scaled}x${y_scaled}"
convert "$IN_FILE" -coalesce -resize "${x_scaled}x${y_scaled}" -fuzz 2% +dither -layers Optimize +map "$OUT_FILE"