rust-icns

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

Documentation: https://docs.rs/icns

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.

License

rust-icns is made available under the MIT License.