icy_sixel

A high-performance, 100% pure Rust implementation of SIXEL graphics encoding and decoding.

What is SIXEL?

SIXEL (Six Pixels) is a bitmap graphics format for terminals, originally developed by DEC for the VT200 series terminals in the 1980s. It allows displaying images directly in terminal emulators that support the format.

Modern terminals with SIXEL support include:

• xterm (with +sixel build option)
• mlterm, foot, WezTerm, Contour, ctx, and many more

Crates

This repository contains two crates:

icy_sixel - Library

The core Rust library for encoding and decoding SIXEL graphics.

cargo add icy_sixel

Features:

• High-quality color quantization (Wu's algorithm + Floyd-Steinberg dithering)
• SIMD-accelerated decoder
• Full transparency support
• Configurable pixel aspect ratio and background mode
• No C dependencies

icy_sixel-cli - Command-Line Tool

A CLI for converting images to/from SIXEL and playing animated GIFs.

cargo install icy_sixel-cli

Commands:

• sixel encode - Convert PNG/JPEG/GIF/WebP to SIXEL
• sixel decode - Convert SIXEL back to PNG
• sixel animate - Play animated GIFs in the terminal

Quick Start

Library Usage

use icy_sixel::{sixel_encode, EncodeOptions};

let rgba = vec![255, 0, 0, 255]; // Red pixel
let sixel = sixel_encode(&rgba, 1, 1, &EncodeOptions::default())?;
print!("{}", sixel);

CLI Usage

# Display image in terminal
sixel encode image.png

# Play animated GIF
sixel animate animation.gif

# Convert SIXEL to PNG
sixel decode image.six -o output.png

Building

git clone https://github.com/mkrueger/icy_sixel
cd icy_sixel

# Build everything
cargo build --release

# Run tests
cargo test

# Run benchmarks
cargo bench

License

Licensed under either of:

• Apache License, Version 2.0 (LICENSE-APACHE)
• MIT License (LICENSE-MIT)

at your option.

Related Projects

• libsixel - The original C implementation
• quantette - Color quantization library used by icy_sixel