Utility to "tint" an Android nine-patch file without breaking it using ImageMagick

tintninepatch

#! /bin/bash

set -e

if [ $# -lt 2 ]; then
	echo Usage: >&2
	echo "    $0 color image..." >&2
	exit 1
fi

color="$1"

shift

for fn in "$@"; do

	g=$(echo $( file "$fn" | sed -nre 's/^.* ([0-9]+) x ([0-9]+),.*$/\1 - 2\n\2 - 2/p' | bc ) | tr " " x)
	
	tmp="$(mktemp)"

	convert "$fn" -gravity center -region "$g" -fill "$color" -fuzz 90% -opaque white "$tmp"

	mv "$tmp" "$fn"
done