Add icns file creation script

assets/create-icns-files.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+# $ ./create-icns-file.sh icon.png
+# https://github.com/alichtman/scripts/blob/master/create-icns-file.sh
+
+# This script creates a .icns file from a single PNG image.
+# Modified from: https://stackoverflow.com/a/20703594
+
+if [ -z "$1" ]; then
+	printf "USAGE\n\t$ ./create-icns-file.sh icon.png"
+	exit
+fi
+
+iconset_dir="Icon.iconset"
+
+mkdir "$iconset_dir"
+sips -z 16 16     "$1" --out "$iconset_dir"/icon_16x16.png
+sips -z 32 32     "$1" --out "$iconset_dir"/icon_16x16@2x.png
+sips -z 32 32     "$1" --out "$iconset_dir"/icon_32x32.png
+sips -z 64 64     "$1" --out "$iconset_dir"/icon_32x32@2x.png
+sips -z 128 128   "$1" --out "$iconset_dir"/icon_128x128.png
+sips -z 256 256   "$1" --out "$iconset_dir"/icon_128x128@2x.png
+sips -z 256 256   "$1" --out "$iconset_dir"/icon_256x256.png
+sips -z 512 512   "$1" --out "$iconset_dir"/icon_256x256@2x.png
+sips -z 512 512   "$1" --out "$iconset_dir"/icon_512x512.png
+cp "$1" "$iconset_dir"/icon_512x512@2x.png
+iconutil -c icns "$iconset_dir"
+rm -R "$iconset_dir"