ICNS encoder & decoder

This JavaScript library provides an encoder and decoder for ICNS files. At the moment the library is limited to PNG and JPEG 2000-based ICNS entries but it wouldn't be too difficult to expand it further in the future. This limits support to Mac OS 10.5 and up.

Encoding

icnsEndec.encode([IconEntry||Object])

The encode function takes an array of IconEntries or objects that provide an OSType and buffer field. It returns a Buffer containing the binary data of the ICNS file.

The OSType must match one of the supported ones on the Supported OSType Table. The buffer field must be a Buffer or an ArrayBuffer.

Example

const fsPromises = require('fs').promises
const icnsEndec  = require('icns-endec')

;(async () => {
  // Encode ic07 and ic08 from PNG images.
  let icnsBuffer = icnsEndec.encode([
    {
      OSType: 'ic07',
      buffer: await fsPromises.readFile('myIcon-128x128.png'),
    },
    new icnsEndec.IconEntry('ic08', await fsPromises.readFile('myIcon-256x256.png')),
  ])
  
  // Write out our ICNS file.
  await fsPromises.writeFile('myIcon.icns', icnsBuffer)
})()

Decoding

icnsEndec.decode(Buffer||ArrayBuffer)

The decode function takes a Buffer or an ArrayBuffer that holds the binary data of an ICNS file. It returns an array of IconEntries.

Example

const fsPromises = require('fs').promises
const icnsEndec  = require('icns-endec')

;(async () => {
  // Retrieve the icons as an array of IconEntries.
  let icns = icnsEndec.decode(await fsPromises.readFile('myIcon.icns'))
  
  // Write out all icons.
  for (let icn of icns) {
    await fsPromises.writeFile(`myIcon-${icn.OSType}.${icn.ext}`)
  }
})()

IconEntry

The IconEntry class stores a Buffer, OSType, extension, and image type, where applicable.

constructor(String, Buffer)

Example

let iconEntry = new IconEntry('ic14', await fsPromises.readFile('myPNG-1024x1024.png'))

buffer

Returns the IconEntry's buffer.

type

Returns the IconEntry's image data type. May be 'PNG' or 'JPEG2000'.

ext

Returns the IconEntry's file extension. May be 'png' or 'jp2'.

OSType

Returns the OSType of the IconEntry.

Supported OSType Table

OSType	Supported
ICON
ICN#
icm#
icm4
icm8
ics#
ics4
ics8
is32
s8mk
icl4
icl8
il32
l8mk
ich#
ich4
ich8
ih32
h8mk
it32
t8mk
icp4
icp5
icp6
ic07	x
ic08	x
ic09	x
ic10	x
ic11	x
ic12	x
ic13	x
ic14	x
ic04
ic05
icsB
icsb