World Library  
Flag as Inappropriate
Email this Article

Apple Icon Image format

Article Id: WHEBN0003793697
Reproduction Date:

Title: Apple Icon Image format  
Author: World Heritage Encyclopedia
Language: English
Subject: OS X, Comparison of image viewers, Portable Network Graphics, CALS Raster file format, FLIC (file format)
Collection: Computer Icons, Graphics File Formats, Os X
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Apple Icon Image format

Apple Icon Image
ICNS icon.
Filename extension .icns
Type code icns
Uniform Type Identifier (UTI) com.apple.icns
Developed by Apple Inc.
Type of format icon file format

The Apple Icon Image format is the icon format used in Apple Inc.'s Mac OS X. It supports icons of 16 × 16, 32 × 32, 48 × 48, 128 × 128, 256 × 256, 512 × 512, and 1024 × 1024 pixels, with both 1- and 8-bit alpha channels and multiple image states (example: open and closed folders). The fixed-size icons can be scaled by the operating system and displayed at any intermediate size.

Contents

  • File structure 1
    • Header 1.1
    • Icon data 1.2
    • Compression 1.3
    • Icon types 1.4
    • Other types 1.5
  • See also 2
  • References 3
  • External links 4

File structure

The file format consists of an 8 byte header, followed by any number of icons.

Header

Offset Size Purpose
0 4 Magic literal, must be "icns" (0x69, 0x63, 0x6e, 0x73)
4 4 Length of file, in bytes, msb first

Icon data

Offset Size Purpose
0 4 Icon type, see OSType below.
4 4 Length of data, in bytes (including type and length), msb first
8 Variable Icon data

Compression

Over time the format has been improved and there is support for compression of some parts of the pixel data. The 32-bit ("is32", "il32", "ih32","it32") pixel data is often compressed (per channel) with a format similar to PackBits.[1]
Some sources mentioned that the OS supports both compressed or uncompressed data chunks.

Icon types

OSType Length (bytes) Size (pixels) Supported OS Version Description
ICON 128 32 1.0 32×32 1-bit mono icon
ICN# 256 32 6.0 32×32 1-bit mono icon with 1-bit mask
icm# 48 16 6.0 16×12 1 bit mono icon with 1-bit mask
icm4 96 16 7.0 16×12 4 bit icon
icm8 192 16 7.0 16×12 8 bit icon
ics# 64 (32 img + 32 mask) 16 6.0 16×16 1-bit mask
ics4 128 16 7.0 16×16 4-bit icon
ics8 256 16 7.0 16x16 8 bit icon
is32 varies (768) 16 8.5 16×16 24-bit icon
s8mk 256 16 8.5 16x16 8-bit mask
icl4 512 32 7.0 32×32 4-bit icon
icl8 1,024 32 7.0 32×32 8-bit icon
il32 varies (3,072) 32 8.5 32x32 24-bit icon
l8mk 1,024 32 8.5 32×32 8-bit mask
ich# 288 48 8.5 48×48 1-bit mask
ich4 1,152 48 8.5 48×48 4-bit icon
ich8 2,304 48 8.5 48×48 8-bit icon
ih32 varies (6,912) 48 8.5 48×48 24-bit icon
h8mk 2,304 48 8.5 48×48 8-bit mask
it32 varies (49,152) 128 10.0 128×128 24-bit icon
t8mk 16,384 128 10.0 128×128 8-bit mask
icp4 varies 16 10.7 16x16 icon in JPEG 2000 or PNG format
icp5 varies 32 10.7 32x32 icon in JPEG 2000 or PNG format
icp6 varies 64 10.7 64x64 icon in JPEG 2000 or PNG format
ic07 varies 128 10.7 128x128 icon in JPEG 2000 or PNG format
ic08 varies 256 10.5 256×256 icon in JPEG 2000 or PNG format
ic09 varies 512 10.5 512×512 icon in JPEG 2000 or PNG format
ic10 varies 1024 10.7 1024×1024 in 10.7 (or 512x512@2x "retina" in 10.8) icon in JPEG 2000 or PNG format
ic11 varies 32 10.8 16x16@2x "retina" icon in JPEG 2000 or PNG format
ic12 varies 64 10.8 32x32@2x "retina" icon in JPEG 2000 or PNG format
ic13 varies 256 10.8 128x128@2x "retina" icon in JPEG 2000 or PNG format
ic14 varies 512 10.8 256x256@2x "retina" icon in JPEG 2000 or PNG format
  • the values inside the brackets () in the length column is the uncompressed length.

Other types

OSType Length (bytes) Description
'TOC ' varies "Table of Contents" a list of all image types in the file, and their sizes (added in Mac OS X 10.7)
'icnV' 4 4-byte big endian float - equal to the bundle version number of Icon Composer.app that created to icon

See also

References

  1. ^ Macintosh Icons

External links

  • [2]


This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.