Android icons creation tool

Are you developing an Android application and have you to convert an image to a set of icons ? Do you want to avoid as much as possible repetitive manual operations ? Here you can find a tool to convert a single image to the set of icons needed by Android for various device screen resolutions. Before starting you need to have:

• a Linux system (or any other unix-like system)
• a working installation of ImageMagick tools

Once you have your system up and running and the tools installed you can go on. Create in  /usr/local/bin (or any other path you are using to store your scripts/executables) a file named android_icon.sh and inside it put the following code:

#!/bin/sh

#
# Davide Airaghi
# Simple "icon creator" for Android development
# Image sizes taken from http://iconhandbook.co.uk/reference/chart/android/
#


echo ""

TYPE="$1"
IMAGE="$2"
RESNAME="$3"
OUTDIR="$4"
SIZES=""

if [ "$RESNAME" != "" ]; then
	RESNAME=$( echo $RESNAME | sed -es/\[^a-zA-Z0-9\\_\]/_/g )
fi


function usage() {

	echo ""
	echo "Usage:"
	echo "android_icon.sh TYPE ORIGINAL_IMAGE RESOURCE_NAME OUTPUT_DIR"
	echo ""
	echo "TYPE can be one of: launcher, actionbar, dialog, tab, contextual, notification"
	echo "" 
	echo "Example"
	echo ""
	echo "android_launger_icon.sh launcher ~/images/my-icon.png my_icon ~/progs/my-app/app/src/main/res"
	echo ""
	echo ""

}

if [ "$TYPE" = "" ]; then
	echo "Type not given"
	usage
	exit 1
fi

case $TYPE in
	launcher)
		SIZES="mdpi-48 hdpi-72 xhdpi-96 xxhdpi-144 xxxhdpi-192"
		;;
	actionbar)
		SIZES="mdpi-32 hdpi-48 xhdpi-64 xxhdpi-96 xxxhdpi-128"
		;;
	dialog)
		SIZES="mdpi-32 hdpi-48 xhdpi-64 xxhdpi-96 xxxhdpi-128"
		;;
	tab)
		SIZES="mdpi-32 hdpi-48 xhdpi-64 xxhdpi-96 xxxhdpi-128"
		;;
	contextual)
		SIZES="mdpi-16 hdpi-24 xhdpi-32 xxhdpi-48 xxxhdpi-64"
		;;
	notification)
		SIZES="mdpi-24 hdpi-36 xhdpi-48 xxhdpi-72 xxxhdpi-96"
		;;
	*)
		echo "Type not valid"	
		usage
		exit 2
		;;
 
esac

if [ "$IMAGE" = "" ]; then
	echo "Image file not given"
	usage
	exit 3
fi

if [ "$RESNAME" = "" ]; then
	echo "Resource name not given"
	usage
	exit 4
fi

if [ "$OUTDIR" = "" ]; then
	echo "Output dir not given"
	usage
	exit 5
fi

if [ ! -f $IMAGE ]; then
	echo "Image file not found"
	exit 6
fi

if [ ! -d $OUTDIR ]; then
	echo "Output dir not found"
	exit 7
fi

IMAGENAME=$(basename $IMAGE)
IMAGENAME="${IMAGENAME%.*}"

PREFIX="mipmap-"

IMG_OK=""
IMG_ERR=""

for i in $SIZES;
do
	ERR=0
	OUTFILE=${OUTDIR}/mipmap-$(echo $i|cut -d- -f1)
	if [ ! -d ${OUTFILE} ]; then
		mkdir -p ${OUTFILE}
		if [ "$?" != "0" ]; then
			echo "Unable to create ${OUTFILE}"
			ERR=1
		fi
	fi
	OUTFILE=${OUTFILE}/${RESNAME}.png
	if [ "$ERR" = "0" ]; then
		SIZE=$(echo $i|cut -d- -f2)
		convert $IMAGE -resize ${SIZE}x${SIZE} -gravity center -extent ${SIZE}x${SIZE} ${OUTFILE}
		if [ "$?" != "0" ]; then
			ERR=1
			echo "Unable to create ${OUTFILE}"
		fi
	else
		echo "Unable to create ${OUTFILE}"
	fi
	if [ "$ERR" = "1" ]; then
		IMG_ERR="${IMG_ERR}$OUTFILE "
	else
		IMG_OK="${IMG_OK}$OUTFILE "	
	fi
done

echo ""
echo "Images created: ${IMG_OK}"
echo "Images not created: ${IMG_ERR}"
echo ""

if [ "${IMG_OK}" = "" ]; then
	exit 255
else
	exit 0
fi

After saving the file you have to make it executable ( chmod +x /usr/local/bin/android_icon.sh ). Now you are ready to convert images into set of icons. The tool needs 4 parameters to do its job:

• TYPE (first parameter) : the type of icon to create (see below)
• ORIGINAL_IMAGE (second parameter) : the path of the image you want to convert
• RESOURCE_NAME (third parameter) : the name of the resource to create. be aware that the tool overwrite any previous resource with the same name!
• OUTPUT_DIR (fourth parameter) : existing path in which save the set of icons  (very often this will be the directory app/src/main/res inside your project)

Currently supported icon type are:

• launcher : icons used in the home screen or in the applications list pages.
• actionbar: icons used in the navigation toolbar displayed in the upper part of the screen
• dialog: icons used in modal boxes
• tab: icons used the tabbed toolbar displayed in the bottom part of the screen
• contextual: icons used for contextual action voices
• notification: icons used in notification popup boxes