UIng

UIng is a Crystal binding for kojix2/libui-ng. You can use the Crystal language to create cross-platform native desktop apps.

Documentation: Guide · English · 日本語 · API Reference

libui-ng uses the native APIs of each platform: Win32 API, Direct2D, and DirectWrite on Windows; Cocoa (AppKit) on macOS; and GTK+ 3.10+ and Pango on Linux/Unix. You get windows, buttons, text boxes, menus, dialogs, drawing areas, and other standard widgets.

Windows	Mac	Linux

📸 Live Documentation: Gallery screenshots are automatically generated by GitHub Actions on Linux, Windows, and macOS.

Supported Platforms

macOS: x86_64 (64-bit), ARM64 (Apple Silicon)
Linux: x86_64 (64-bit), ARM64
Windows: x86_64 (64-bit, MSVC and MSYS2 UCRT64)

MinGW64 is no longer supported; use the MSYS2 UCRT64 environment for GNU-style builds.

Installation

Add the dependency to your shard.yml:

dependencies:
  uing:
    github: kojix2/uing

Run shards install. The post-install script downloads the required libui-ng binary for the current platform. See the installation guide for platform-specific setup.

Quick Start

Create hello.cr:

require "uing"

UIng.init

window = UIng::Window.new("Hello World", 300, 200)
window.on_closing do
  UIng.quit
  true
end

button = UIng::Button.new("Click me")
button.on_clicked do
  window.msg_box("Info", "Button clicked!")
end

window.child = button
window.show

UIng.main
UIng.uninit

Run it with:

crystal run hello.cr

To run the full control gallery from a checkout:

git clone https://github.com/kojix2/uing
cd uing
shards install
crystal run examples/crimage/control_gallery.cr

Continue with the First Steps guide. The optional block-based DSL is covered in Coding Styles.

Examples Gallery

This gallery shows screenshots of example on three platforms (Ubuntu, Windows, macOS).
Images are automatically generated and stored in the screenshots branch.