justjp2

Pure Rust JPEG 2000 (JP2/J2K) encoder and decoder.

Features

• Encode/Decode JP2 file format and raw J2K codestreams
• Lossless (5/3 DWT + RCT) and lossy (9/7 DWT + ICT) compression
• Multi-tile support with parallel encoding via rayon
• Reduce resolution decoding (decode at lower resolution levels)
• Region of interest decoding (crop to a specific area)
• Format auto-detection (JP2 vs J2K)
• No unsafe code, no C dependencies

Quick Start

use justjp2::{Image, Component, EncodeParams, CodecFormat};

// Encode
let image = Image {
    width: 256,
    height: 256,
    components: vec![Component {
        data: vec![128i32; 256 * 256],
        width: 256,
        height: 256,
        precision: 8,
        signed: false,
        dx: 1,
        dy: 1,
    }],
};

let params = EncodeParams::default(); // lossless JP2
let bytes = justjp2::encode(&image, &params).unwrap();

// Decode
let decoded = justjp2::decode(&bytes).unwrap();
assert_eq!(decoded.width, 256);

Supported Formats

API

// Decode (auto-detects JP2 vs J2K)
justjp2::decode(data: &[u8]) -> Result<Image>

// Decode at reduced resolution
justjp2::decode_with_reduce(data: &[u8], reduce: u32) -> Result<Image>

// Decode a specific region
justjp2::decode_region(data: &[u8], x0: u32, y0: u32, x1: u32, y1: u32) -> Result<Image>

// Encode
justjp2::encode(image: &Image, params: &EncodeParams) -> Result<Vec<u8>>

Architecture

Built from the ground up following ITU-T T.800 (JPEG 2000 Part 1):

License

Apache-2.0