Create iOS application icons from one PDF file. Requires ImageMagick & GhostScript

Iconizer.sh

#!/bin/zsh

#
#
# Iconizer shell script by Steve Richey (srichey@floatlearning.com)
# Modified by Rich Ellis (rich@richellis.net) based on contributions on Github from crishoj, giria
# Further modified by Nick Pannuto (sneakyness@sneakyness.com) based on gist comments from previous forks
# https://gist.github.com/steverichey/8493f3bd31ae71a9c933/forks
# 
# Changelog:
#  - removed ./ from in front of $2's to allow for absolute paths
#  - updated destination filename to target new 'Assets.xcassets' filename
#  - uses zsh instead of sh
#  - ran through ShellCheck until clean
#  - updated with missing sizes
#  - now pads pdf at h*83.33, w*75 of icon size (generally looks nicer)
#
# Todo:
#  - padding and alignment options
#  - insert missing sizes into correct slots
#  - check for IM/GS up front
#  - check if brew
#  - installation prompts on missing deps
# 
# This is a simple tool to generate all necessary app icon sizes and the JSON file for an *EXISTING* Xcode project from one file.
# To use: specify the path to your vector graphic (PDF format) and the path to your Xcode folder containing Images.xcassets
# Example: sh iconizer.sh MyVectorGraphic.pdf MyXcodeProject
#
# Requires ImageMagick: http://www.imagemagick.org/
# Requires GhostScript: http://www.ghostscript.com/
#
# Install dependencies with Homebrew: http://brew.sh/
#    brew install imagemagick
#    brew install ghostscript

# Exit on first error
set -e

if [ "$#" -eq  "0" ]
then 
    # TODO: check alias
    printf "\nUsage:"
    printf "\n sh iconizer.sh file.pdf FolderName"
    printf "\n"
    printf "\nOther Commands:"
    printf "\n -alias            Alias Installation Instructions"
    printf "\n -deps             Install ImageMagick and GhostScript via Brew 🍺"
    printf "\n -help             Display This Output"
    printf "\n"
elif [[ $1 == '-help' ]]
then 
    sh "$0"
elif [[ $1 == '-alias' ]]
then
    printf "\n"
    if [ ! -d "$HOME/scripts" ]
    then 
        printf "\n~/scripts does not exist, creating it"
        mkdir "$HOME/scripts"
    fi
    printf "\ncopying %s to ~/scripts/%s" "$0" "$0"
    cp "$0" "$HOME/scripts"
    if (( ${+aliases[iconizer]} ))
    then
        whence iconizer 
    else
    echo "iconizer not aliased, adding alias to zshrc"
    echo "alias iconizer=\"zsh $HOME/scripts/iconizer.sh\"" >> "$HOME/.zshrc"
    fi 
elif [[ $1 == '-deps' ]]
then
    # TODO: check for brew?
    # TODO: check versions first?
    brew install imagemagick
    brew install ghostscript
elif [ $# -ne 2 ]
  then
    # TODO: check if aliased or using script
    printf "\nUsage: sh iconizer.sh file.pdf FolderName\n"
elif [ ! -e "$1" ]
    then
        printf "\nDid not find file %s, expected path to a vector image file.\n" "$1"
elif [ "${1: -4}" != ".pdf" ]
    then
        printf "\nFile %s is not a vector image file! Expected PDF file.\n" "$1"
elif [ ! -d "$2/Assets.xcassets/AppIcon.appiconset/" ]
    then
        # TODO: ask to install IM
        # TODO: better search for assets folder
        printf "\nDid not find Xcode folder %s, expected folder which contains Assets.xcassets/AppIcon.appiconset/ \n" "$2"
elif [ ! -x "$(command -v convert)" ]
    then
        printf "\nExecutable 'convert' not found in path. Please install ImageMagick.\n"
elif [ ! -x "$(command -v gs)" ]
    then
        # TODO: ask to install GS
        printf "\nExecutable 'gs' not found in path. Please install GhostScript.\n"
else
    printf "Generating icons from" 
    printf "\n    %s" "$1" 
    printf "\n into"
    printf "\n    %s/Assets.xcassets/AppIcon.appiconset/…\n" "$2"

printf "\nFor Sizes:\n"
# TODO: split into groups for
# iphone, ipad, carplay, mac, applewatch
# TODO: toggle groups
# TODO: extra size options
# TODO: Padding opt
    for i in 16 20 29 32 40 48 50 55 57 58 60 64 72 76 80 87 88 100 114 120 128 144 152 167 172 180 196 216 256 512 1024
        do
            # height is 83.33% of image size
            # width is 75% of image size
            sH=$(bc <<< "$i * 0.8333") 
            sW=$(bc <<< "$i * 0.75")
            printf "%sx%s " "$i" "$i"
            convert -density 463 "$1" -background transparent -gravity center -scale ""$sW"x$sH" -extent ""$i"x$i" "$2"/Assets.xcassets/AppIcon.appiconset/appicon_$i.png
    done
    printf "\n Images successfully generated…"
    printf "\n Writing Contents.json file…\n"

    printf '{"images":[
{\n"size":"29x29",\n"idiom":"iphone",\n"filename":"appicon_29.png",\n"scale":"1x"\n},
{\n"size":"29x29",\n"idiom":"iphone",\n"filename":"appicon_58.png",\n"scale":"2x"\n},
{\n"size":"29x29",\n"idiom":"iphone",\n"filename":"appicon_87.png",\n"scale":"3x"\n},
{\n"size":"40x40",\n"idiom":"iphone",\n"filename":"appicon_80.png",\n"scale":"2x"\n},
{\n"size":"40x40",\n"idiom":"iphone",\n"filename":"appicon_120.png",\n"scale":"3x"\n},
{\n"size":"57x57",\n"idiom":"iphone",\n"filename":"appicon_57.png",\n"scale":"1x"\n},
{\n"size":"57x57",\n"idiom":"iphone",\n"filename":"appicon_114.png",\n"scale":"2x"\n},
{\n"size":"60x60",\n"idiom":"iphone",\n"filename":"appicon_120.png",\n"scale":"2x"\n},
{\n"size":"60x60",\n"idiom":"iphone",\n"filename":"appicon_180.png",\n"scale":"3x"\n},
{\n"size":"29x29",\n"idiom":"ipad",\n"filename":"appicon_29.png",\n"scale":"1x"\n},
{\n"size":"29x29",\n"idiom":"ipad",\n"filename":"appicon_58.png",\n"scale":"2x"\n},
{\n"size":"40x40",\n"idiom":"ipad",\n"filename":"appicon_40.png",\n"scale":"1x"\n},
{\n"size":"40x40",\n"idiom":"ipad",\n"filename":"appicon_80.png",\n"scale":"2x"\n},
{\n"size":"50x50",\n"idiom":"ipad",\n"filename":"appicon_50.png",\n"scale":"1x"\n},
{\n"size":"50x50",\n"idiom":"ipad",\n"filename":"appicon_100.png",\n"scale":"2x"\n},
{\n"size":"72x72",\n"idiom":"ipad",\n"filename":"appicon_72.png",\n"scale":"1x"\n},
{\n"size":"72x72",\n"idiom":"ipad",\n"filename":"appicon_144.png",\n"scale":"2x"\n},
{\n"size":"76x76",\n"idiom":"ipad",\n"filename":"appicon_76.png",\n"scale":"1x"\n},
{\n"size":"76x76",\n"idiom":"ipad",\n"filename":"appicon_152.png",\n"scale":"2x"\n},
{\n"size":"83.5x83.5",\n"idiom":"ipad",\n"filename":"appicon_167.png",\n"scale":"2x"\n},
{\n"size":"120x120",\n"idiom":"car",\n"filename":"appicon_120.png",\n"scale":"1x"\n},
{\n"size":"16x16",\n"idiom":"mac",\n"filename":"appicon_16.png",\n"scale":"1x"\n},
{\n"size":"16x16",\n"idiom":"mac",\n"filename":"appicon_32.png",\n"scale":"2x"\n},
{\n"size":"32x32",\n"idiom":"mac",\n"filename":"appicon_32.png",\n"scale":"1x"\n},
{\n"size":"32x32",\n"idiom":"mac",\n"filename":"appicon_64.png",\n"scale":"2x"\n},
{\n"size":"128x128",\n"idiom":"mac",\n"filename":"appicon_128.png",\n"scale":"1x"\n},
{\n"size":"128x128",\n"idiom":"mac",\n"filename":"appicon_256.png",\n"scale":"2x"\n},
{\n"size":"256x256",\n"idiom":"mac",\n"filename":"appicon_256.png",\n"scale":"1x"\n},
{\n"size":"256x256",\n"idiom":"mac",\n"filename":"appicon_512.png",\n"scale":"2x"\n},
{\n"size":"512x512",\n"idiom":"mac",\n"filename":"appicon_512.png",\n"scale":"1x"\n},
{\n"size":"512x512",\n"idiom":"mac",\n"filename":"appicon_1024.png",\n"scale":"2x"\n}\n],
"info":{\n"version":1,\n"author":"xcode"\n}\n}' > "$2/Assets.xcassets/AppIcon.appiconset/Contents.json"

    printf "\n🎉 Complete! 🎉\n"
fi