rust-icns

A Rust library for encoding/decoding Apple Icon Image (.icns) files.

Overview

The icns crate implements reading and writing of ICNS files, encoding and decoding images into and out of an ICNS icon family, converting those images to other pixel formats (in case you need to transfer the image data to another library that expects the data in a particular format), and saving/loading those images to/from PNG files.

The crate documentation has more information about how to use the library.

Example usage

extern crate icns;
use icns::{IconFamily, IconType, Image};
use std::fs::File;
use std::io::{BufReader, BufWriter};

fn main() {
    // Load an icon family from an ICNS file.
    let file = BufReader::new(File::open("16.icns").unwrap());
    let mut icon_family = IconFamily::read(file).unwrap();

    // Extract an icon from the family and save it as a PNG.
    let image = icon_family.get_icon_with_type(IconType::RGB24_16x16).unwrap();
    let file = BufWriter::new(File::create("16.png").unwrap());
    image.write_png(file).unwrap();

    // Read in another icon from a PNG file, and add it to the icon family.
    let file = BufReader::new(File::open("32.png").unwrap());
    let image = Image::read_png(file).unwrap();
    icon_family.add_icon(&image).unwrap();

    // Save the updated icon family to a new ICNS file.
    let file = BufWriter::new(File::create("16-and-32.icns").unwrap());
    icon_family.write(file).unwrap();
}

Supported icon types

ICNS files can contain a number of different icon types. This library supports the most commonly-used types, but some of the older ones are not yet supported. The table below indicates which types are currently supported; see https://en.wikipedia.org/wiki/Apple_Icon_Image_format#Icon_types for more information about each type.

The biggest limitation at this time is that a number of the newer icon types can be encoded with either PNG or JPEG 2000 data, but this library does not yet support JPEG 2000; attempting to decode such an icon will result an an error value being returned (although you can still decode other icons from the same ICNS file). The reason for this is that I don't currently know of any JPEG 2000 libraries for Rust; if one exists, please feel free to file a bug or send a pull request.

OSType	Description	Supported?
ICON	32×32 1-bit icon	No
ICN#	32×32 1-bit icon with 1-bit mask	No
icm#	16×12 1-bit icon with 1-bit mask	No
icm4	16×12 4-bit icon	No
icm8	16×12 8-bit icon	No
ics#	16×16 1-bit mask	No
ics4	16×16 4-bit icon	No
ics8	16x16 8-bit icon	No
is32	16×16 24-bit icon	Yes
s8mk	16x16 8-bit mask	Yes
icl4	32×32 4-bit icon	No
icl8	32×32 8-bit icon	No
il32	32x32 24-bit icon	Yes
l8mk	32×32 8-bit mask	Yes
ich#	48×48 1-bit mask	No
ich4	48×48 4-bit icon	No
ich8	48×48 8-bit icon	No
ih32	48×48 24-bit icon	Yes
h8mk	48×48 8-bit mask	Yes
it32	128×128 24-bit icon	Yes
t8mk	128×128 8-bit mask	Yes
icp4	16x16 32-bit PNG/JP2 icon	PNG only
icp5	32x32 32-bit PNG/JP2 icon	PNG only
icp6	64x64 32-bit PNG/JP2 icon	PNG only
ic07	128x128 32-bit PNG/JP2 icon	PNG only
ic08	256×256 32-bit PNG/JP2 icon	PNG only
ic09	512×512 32-bit PNG/JP2 icon	PNG only
ic10	512x512@2x "retina" 32-bit PNG/JP2 icon	PNG only
ic11	16x16@2x "retina" 32-bit PNG/JP2 icon	PNG only
ic12	32x32@2x "retina" 32-bit PNG/JP2 icon	PNG only
ic13	128x128@2x "retina" 32-bit PNG/JP2 icon	PNG only
ic14	256x256@2x "retina" 32-bit PNG/JP2 icon	PNG only

License

rust-icns is made available under the MIT License.