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 |
|---|---|---|
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📸 Live Documentation: All screenshots in the README are automatically generated by GitHub Actions on every push, ensuring cross-platform compatibility (Linux, Windows, macOS).
- macOS: x86_64 (64-bit), ARM64 (Apple Silicon)
- Linux: x86_64 (64-bit), ARM64
- Windows: x86_64 (64-bit, MSVC, MinGW, and UCRT)
Add the dependency to your shard.yml:
dependencies:
uing:
github: kojix2/uingRun shards install. The post-install script downloads the required libui-ng binary for the current platform. See the installation guide for platform-specific setup.
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.uninitRun it with:
crystal run hello.crTo 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.crContinue with the First Steps guide. The optional block-based DSL is covered in Coding Styles.
This gallery shows screenshots of example on three platforms (Ubuntu, Windows, macOS).
Images are automatically generated and stored in the screenshots branch.
| Control | Ubuntu | Windows | macOS |
|---|---|---|---|
| Window |  |
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| Toolbar |  |
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Note: Toolbar is a feature specific to kojix2/libui-ng. It is experimental and may change.
| Control | Ubuntu | Windows | macOS |
|---|---|---|---|
| Button |  |
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| Checkbox |  |
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| ColorButton |  |
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| Combobox |  |
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| DateTimePicker |  |
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| EditableCombobox |  |
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| Entry |  |
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| FontButton |  |
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| Label |  |
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| MultilineEntry |  |
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| Progressbar |  |
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| RadioButtons |  |
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| Separator |  |
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| Slider |  |
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| Spinbox |  |
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| Container | Ubuntu | Windows | macOS |
|---|---|---|---|
| Box (Horizontal) |  |
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| Box (Vertical) |  |
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| Tab |  |
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| Form |  |
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| Group |  |
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| Grid |  |
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| Grid (Calculator) |  |
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| Example | Ubuntu | Windows | macOS |
|---|---|---|---|
| basic_table |  |
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| csv_viewer |  |
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| advanced_table |  |
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| Example | Ubuntu | Windows | macOS |
|---|---|---|---|
| basic_area |  |
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| area_basic_shapes |  |
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| area_colors_and_brushes |  |
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| area_analog_clock |  |
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| area_matrix |  |
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| basic_draw_text |  |
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| reversi |  |
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| area_breakout |  |
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| boid3d |  |
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| Example | Ubuntu | Windows | macOS |
|---|---|---|---|
| basic_menu |  |
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| Example | Ubuntu | Windows | macOS |
|---|---|---|---|
| basic_msg_box |  |
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| basic_msg_box_error |  |
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require "uing/crimage" enables optional helpers for reading images, converting
CrImage pixels, and passing CrImage colors to UIng controls. Applications using
these helpers must declare crimage in their own shard.yml. Plain
require "uing" does not load it. CrImage examples are kept in
examples/crimage/. See the ImageView guide
for usage and image ownership rules.
| Example | Ubuntu | Windows | macOS |
|---|---|---|---|
| area_draw_image |  |
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| basic_image_view |  |
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Note: Image display is a feature introduced in kojix2/libui-ng. This feature is not present in the original libui-ng.
See the development and contribution guide. Bug reports, pull requests, and articles about UIng are welcome.
MIT License