Sixel Graphics Experiments

A collection of experiments and projects using Sixel graphics - a bitmap graphics format for terminals.

Sixel allows rendering pixel-perfect graphics directly in terminal emulators that support it, without requiring a GUI framework.

Projects

Sixtop - System Monitor

A terminal-based system monitor with real-time updating graphs, similar to Activity Monitor or Task Manager.

Features:

• Five metric views: Energy, CPU, I/O, Memory, Network
• Real-time graphs with historical data
• Cross-platform support (Windows/macOS/Linux)
• Battery status and power monitoring

See the Sixtop README for details

Snake Game

A fully playable snake game rendered entirely in Sixel graphics, including a custom bitmap font for text rendering.

Features:

• Pure Sixel rendering (no ANSI text mixing)
• Custom 5x7 bitmap font
• Cross-platform support (Windows/macOS/Linux)
• 16x16 game grid with smooth graphics

See the Snake README for details

Interactive GUI Framework

A proof-of-concept interactive terminal GUI framework demonstrating rich UI components rendered entirely in the terminal using Sixel graphics (and PNG animation on iTerm2).

Features:

• 8 interactive component types: Buttons, Checkboxes, Radio Buttons, Text Input, Sliders, Progress Bars, List Boxes, and Image Display
• Keyboard navigation with Tab/Shift+Tab and arrow keys
• Cross-platform support (Windows/macOS/Linux)
• Async rendering for responsive input handling
• Native iTerm2 inline image protocol for fast macOS rendering
• YAML-based declarative GUI configuration

See the GUI README for details

Terminal Compatibility

Sixel graphics require a compatible terminal emulator:

Platform	Terminals
macOS	iTerm2
Windows	Windows Terminal, mintty (Git Bash)
Linux	mlterm, xterm (with Sixel enabled), foot, kitty

Testing Sixel Support

You can test if your terminal supports Sixel by running:

cat test.sixel

If you see colored horizontal bars, your terminal supports Sixel graphics.

Repository Structure

sixel/
├── README.md          # This file
├── test.sixel         # Simple Sixel test file
├── sixtop/            # System monitor project
│   ├── README.md
│   ├── Makefile
│   ├── Pipfile
│   ├── main.py
│   ├── renderer.py
│   ├── sixel.py
│   ├── metrics.py
│   └── demo/
│       └── screenshot.png
├── snake/             # Snake game project
│   ├── README.md
│   ├── Makefile
│   ├── Pipfile
│   ├── main.py
│   ├── game.py
│   ├── sixel.py
│   ├── renderer.py
│   └── demo/
│       └── sixel-snake.gif
└── gui/               # Interactive GUI framework
    ├── README.md
    ├── Makefile
    ├── Pipfile
    ├── main.py
    ├── app_loop.py
    ├── gui.py
    ├── renderer.py
    ├── sixel.py
    ├── config.py
    ├── terminals/
    └── demo/
        └── squirel.png

About Sixel

Sixel (short for "six pixels") is a graphics format that encodes images as sequences of characters. Each Sixel character represents a column of 6 vertical pixels, with a bitmask indicating which pixels are "on" for a given color.

Key characteristics:

• 6 pixels per character: Each character encodes 6 vertical pixels
• Multiple colors: Colors are defined with RGB values (0-100 range)
• Terminal-native: No external graphics libraries needed
• Streaming: Can be output progressively

The format was originally developed by DEC for use with their terminals in the 1980s and has seen renewed interest for terminal-based graphics applications.