generate ICNS file from master PNG image

generate_icns.sh

#!/bin/bash
 
#Usage:   
#generate_icns.sh /path/to/mastericon.png

if [ $# -ne 1 ]; then
    echo "error: $# arguments expected 1"
    echo "usage: generate_icns.sh /path/to/mastericon.png"
    exit 1
fi

icon=$1

width=`sips -g pixelHeight $icon | tr -dc '0-9'`
height=`sips -g pixelWidth $icon | tr -dc '0-9'`

echo $icon is $width x $height pixels

if [ $width -lt 1024 ]; then
    echo error: expected master image pixel dim of at least 1024x1024
    exit 1
fi

if [ $width -ne $height ]; then
    echo error: expected square aspect ratio
    exit 1
fi

 
i=0
 
sizes=(16 32 128 256 512)
 
iconset=generated.iconset
icnfile=generated.icns
 
echo working into $icnfile
 
if [ -d $iconset ]; then
  rm -rf $iconset
fi

if [ -e $icnfile ]; then
  rm -rf $icnfile
fi
 
mkdir -p $iconset
 
base=iconbase.png
 
cp $1 $iconset/$base
 
echo working on $1
 
while [ $i -lt ${#sizes[@]} ]; do
 
nextsize=${sizes[$i]}
nextsize2x=$((2*nextsize))
 
nextname=icon_$nextsize'x'$nextsize.png
nextname2x=icon_$nextsize'x'$nextsize@2x.png
 
echo generating files $nextname and $nextname2x 
 
cp $iconset/$base $iconset/$nextname
`sips -Z $nextsize $iconset/$nextname &>/dev/null` 
 
cp $iconset/$base $iconset/$nextname2x
`sips -Z $nextsize2x $iconset/$nextname2x &>/dev/null`

 
: $[ i++ ]
 
done

rm $iconset/$base

`iconutil -c icns -o $icnfile $iconset`

if [ $? -ne 0 ]; then
    echo "$icnfile not created"
    exit 1
fi

echo "$icnfile created successfully"