generate_icon_assets.sh

#!/bin/sh

# exit if there are any errors
set -e

# pretty output
info() {
    local green="\033[1;32m"
    local normal="\033[0m"
    echo "[${green}INFO${normal}] $1"
}

# pretty errors
error() {
     local red="\033[1;31m"
     local normal="\033[0m"
     echo "[${red}ERROR${normal}] $1"
}

# check ImageMagick
command -v convert >/dev/null 2>&1 || { error >&2 "The ImageMagick is not installed. Please use brew to install it first."; exit -1; }

DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
BASE="$DIR/../iTunes/iTunesArtwork@2x.png"
OUTPUT="$DIR/../Blink/Assets.xcassets/AppIcon.appiconset/"

# ensure that the path points to a valid file.
if [ ! -f "$BASE" ]
then
	echo "Invalid path to base file."
	exit 1
fi

# takes in the dimension of the icon (it assumes the icon is a square) and the name of the file to save the icon to.
createIconImage()
{
	iconDimension=$1
	iconName=$2

	convert "$BASE" -resize ${iconDimension}x${iconDimension}^ -gravity center -extent ${iconDimension}x${iconDimension} $OUTPUT/$iconName
}

info 'Generating app icons ...'

info '20pt iPhone Notification 2x'
createIconImage 40 icon-40.png

info '20pt iPhone Notification 3x'
createIconImage 60 icon-60.png

info '29pt Settings/Spotlight 2x'
createIconImage 58 icon-58.png

info '29pt Settings/Spotlight 3x'
createIconImage 87 icon-87.png

info '40pt Spotlight 2x'
createIconImage 80 icon-80.png

info '40pt Spotlight 3x'
createIconImage 120 icon-121.png

info '60pt iPhone app 2x'
createIconImage 120 icon-120.png

info '60pt iPhone app 3x'
createIconImage 180 icon-180.png