make app icon for iOS using ffmpeg

make-app-icon-ffmpeg.sh

if [ "$#" -eq 2 ]
then
mkdir $2

ffmpeg -y -i $1 -vf scale=20x20 $2/icon-20x20@1x.png
ffmpeg -y -i $1 -vf scale=40x40 $2/icon-20x20@2x.png
ffmpeg -y -i $1 -vf scale=60x60 $2/icon-20x20@3x.png

ffmpeg -y -i $1 -vf scale=29x29 $2/icon-29x29@1x.png
ffmpeg -y -i $1 -vf scale=58x58 $2/icon-29x29@2x.png
ffmpeg -y -i $1 -vf scale=87x87 $2/icon-29x29@3x.png

ffmpeg -y -i $1 -vf scale=40x40 $2/icon-40x40@1x.png
ffmpeg -y -i $1 -vf scale=80x80 $2/icon-40x40@2x.png
ffmpeg -y -i $1 -vf scale=120x120 $2/icon-40x40@3x.png

ffmpeg -y -i $1 -vf scale=120x120 $2/icon-60x60@2x.png
ffmpeg -y -i $1 -vf scale=180x180 $2/icon-60x60@3x.png

ffmpeg -y -i $1 -vf scale=76x76 $2/icon-76x76@1x.png
ffmpeg -y -i $1 -vf scale=152x152 $2/icon-76x76@2x.png

ffmpeg -y -i $1 -vf scale=167x167 $2/icon-83.5x83.5@2x.png

ffmpeg -y -i $1 -vf scale=1024x1024 $2/icon-itunesartwork@2x.png

cat <<EOT > $2/Contents.json
{
  "images" : [
    {
      "size" : "20x20",
      "idiom" : "iphone",
      "filename" : "icon-20x20@2x.png",
      "scale" : "2x"
    },
    {
      "size" : "20x20",
      "idiom" : "iphone",
      "filename" : "icon-20x20@3x.png",
      "scale" : "3x"
    },
    {
      "size" : "29x29",
      "idiom" : "iphone",
      "filename" : "icon-29x29@1x.png",
      "scale" : "1x"
    },
    {
      "size" : "29x29",
      "idiom" : "iphone",
      "filename" : "icon-29x29@2x.png",
      "scale" : "2x"
    },
    {
      "size" : "29x29",
      "idiom" : "iphone",
      "filename" : "icon-29x29@3x.png",
      "scale" : "3x"
    },
    {
      "size" : "40x40",
      "idiom" : "iphone",
      "filename" : "icon-40x40@2x.png",
      "scale" : "2x"
    },
    {
      "size" : "40x40",
      "idiom" : "iphone",
      "filename" : "icon-40x40@3x.png",
      "scale" : "3x"
    },
    {
      "size" : "60x60",
      "idiom" : "iphone",
      "filename" : "icon-60x60@2x.png",
      "scale" : "2x"
    },
    {
      "size" : "60x60",
      "idiom" : "iphone",
      "filename" : "icon-60x60@3x.png",
      "scale" : "3x"
    },
    {
      "size" : "20x20",
      "idiom" : "ipad",
      "filename" : "icon-20x20@1x.png",
      "scale" : "1x"
    },
    {
      "size" : "20x20",
      "idiom" : "ipad",
      "filename" : "icon-20x20@2x.png",
      "scale" : "2x"
    },
    {
      "size" : "29x29",
      "idiom" : "ipad",
      "filename" : "icon-29x29@1x.png",
      "scale" : "1x"
    },
    {
      "size" : "29x29",
      "idiom" : "ipad",
      "filename" : "icon-29x29@2x.png",
      "scale" : "2x"
    },
    {
      "size" : "40x40",
      "idiom" : "ipad",
      "filename" : "icon-40x40@1x.png",
      "scale" : "1x"
    },
    {
      "size" : "40x40",
      "idiom" : "ipad",
      "filename" : "icon-40x40@2x.png",
      "scale" : "2x"
    },
    {
      "size" : "76x76",
      "idiom" : "ipad",
      "filename" : "icon-76x76@1x.png",
      "scale" : "1x"
    },
    {
      "size" : "76x76",
      "idiom" : "ipad",
      "filename" : "icon-76x76@2x.png",
      "scale" : "2x"
    },
    {
      "size" : "83.5x83.5",
      "idiom" : "ipad",
      "filename" : "icon-83.5x83.5@2x.png",
      "scale" : "2x"
    },
    {
      "size" : "1024x1024",
      "idiom" : "ios-marketing",
      "filename" : "icon-itunesartwork@2x.png",
      "scale" : "1x"
    }
  ],
  "info" : {
    "version" : 1,
    "author" : "ldenoue"
  }
}
EOT
else
    echo "please pass your image filename and a directory to put results in"
    exit 1
fi