Convert 3x scaled images to Android drawable resources

convertImages.sh

#!/bin/bash


# images (@3x) to 
# drawable-xxhdpi(3x),
# drawable-xhdpi(2x),
# drawable-mdpi(1x)

# Usage
# -------
#
# Make script as executable:
# $ chmod -x convertImages.sh
#
# Install imagemagick if needed
# (MaOSX) $ brew install imagemagick
# (Linux) $ apt-get install imagemagick
#
# Run script
# $ sh convertImages.sh /path/to/imagesDir/

SRC=$1

# res folders locations
DIR_XXHDPI=$SRC/res/drawable-xxhdpi/ #3x
DIR_XHDPI=$SRC/res/drawable-xhdpi/ #2x
DIR_MDPI=$SRC/res/drawable-mdpi/ #1x

CreateCleanFolder () {

local directory=$1

if [ -d "$directory" ]; then
    rm -rf "$directory"
fi
mkdir -p "$directory"	

}

CreateResFolder () {

local directory=$1
local scale=$2

CreateCleanFolder $directory

cp $SRC/*.png $directory

for image in $directory/*.png;
do
    convert $image -resize $scale $image;

    # rename files to lower case
    local output_name=$(echo "$image" | tr '[:upper:]' '[:lower:]')
    mv $image $output_name
done

}

CreateResFolder $DIR_XXHDPI 100%

CreateResFolder $DIR_XHDPI 66.7%

CreateResFolder $DIR_MDPI 33.3%

echo "DONE"