LibUI

:radio_button: libui - a portable GUI library - for Ruby

Installation

gem install libui

• The gem package contains the official release of the libui shared library versions 4.1 for Windows, Mac, and Linux.
  • Namely libui.dll, libui.dylib, and libui.so (only 1.8MB in total).
• No dependency
  • The libui gem uses the standard Ruby library Fiddle to call C functions.

Windows	Mac	Linux

Note:

• If you are using the 32-bit (x86) version of Ruby, you need to download the 32-bit (x86) native dll. See Development.
• On Windows, libui may not work due to missing DLLs. In that case, you need to install Visual C++ Redistributable. See (#48)

Usage

require 'libui'

UI = LibUI

UI.init

main_window = UI.new_window('hello world', 200, 100, 1)

button = UI.new_button('Button')

UI.button_on_clicked(button) do
  UI.msg_box(main_window, 'Information', 'You clicked the button')
end

UI.window_on_closing(main_window) do
  puts 'Bye Bye'
  UI.control_destroy(main_window)
  UI.quit
  0
end

UI.window_set_child(main_window, button)
UI.control_show(main_window)

UI.main
UI.quit

See examples directory.

General Rules

Compared to original libui written in C,

• The method names are snake_case.
• If the last argument is nil, it can be omitted.
• You can pass a block as a callback.
  • The block will be converted to a Proc object and added to the last argument.
  • Even in that case, it is possible to omit the last argument when nil.

You can use the documentation for libui's Go bindings as a reference.

DSLs for LibUI

LibUI is intentionally not object-oriented because it is a thin Ruby wrapper (binding) for the procedural C libui library, so it mirrors its API structure.

It is recommended that you build actual applications using a DSL for LibUI because DSLs enable writing object-oriented code the Ruby way (instead of procedural code the C way):

• Glimmer DSL for LibUI
• libui_paradise

How to use fiddle pointers?

require 'libui'
UI = LibUI
UI.init

Convert a pointer to a string.

label = UI.new_label("Ruby")
p pointer = UI.label_text(label) # #<Fiddle::Pointer>
p pointer.to_s # Ruby

If you need to use C structs, you can do the following.

font_button = UI.new_font_button

# Allocate memory 
font_descriptor = UI::FFI::FontDescriptor.malloc
font_descriptor.to_ptr.free = Fiddle::RUBY_FREE
# font_descriptor = UI::FFI::FontDescriptor.malloc(Fiddle::RUBY_FREE) # fiddle 1.0.1 or higher

UI.font_button_on_changed(font_button) do
  UI.font_button_font(font_button, font_descriptor)
  p family:  font_descriptor.Family.to_s,
    size:    font_descriptor.Size,
    weight:  font_descriptor.Weight,
    italic:  font_descriptor.Italic,
    stretch: font_descriptor.Stretch
end

• Callbacks
  • In Ruby/Fiddle, a C callback function is written as an object of Fiddle::Closure::BlockCaller or Fiddle::Closure. In this case, you need to be careful about Ruby's garbage collection. If the function object is collected, memory will be freed and a segmentation violation will occur when the callback is invoked.

# to a local variable to prevent it from being collected by GC.
handler.MouseEvent   = (c1 = Fiddle::Closure::BlockCaller.new(0, [0]) {})
handler.MouseCrossed = (c2 = Fiddle::Closure::BlockCaller.new(0, [0]) {})
handler.DragBroken   = (c3 = Fiddle::Closure::BlockCaller.new(0, [0]) {})

How to create an executable (.exe) on Windows

OCRA (One-Click Ruby Application) builds Windows executables from Ruby source code.

• https://github.com/larsch/ocra/

In order to build a exe with Ocra, include 3 DLLs from ruby_builtin_dlls folder:

ocra examples/control_gallery.rb        ^
  --dll ruby_builtin_dlls/libssp-0.dll  ^
  --dll ruby_builtin_dlls/libgmp-10.dll ^
  --dll ruby_builtin_dlls/libffi-7.dll  ^
  --gem-all=fiddle                      ^

Add additional options below if necessary.

  --window                              ^
  --add-all-core                        ^
  --chdir-first                         ^
  --icon assets\app.ico                 ^
  --verbose                             ^
  --output out\gallery.exe

Development

LibUI is not object-oriented, but it provides high portability with a minimal implementation.

git clone https://github.com/kojix2/libui
cd libui
bundle install
bundle exec rake vendor:default # download shared libraries for all platforms
bundle exec rake test

You can use the following rake tasks to download the shared library required for your platform.

rake -T

rake vendor:default      # Downlaod [linux_x64, mac_arm, windows_x64] to vendor directory
rake vendor:linux_x64    # Download libui.so for Linux to vendor directory
rake vendor:linux_x86    # Download libui.so for Linux to vendor directory
rake vendor:mac_arm      # Download libui.dylib for Mac to vendor directory (universal binary)
rake vendor:mac_x64      # Download libui.dylib for Mac to vendor directory
rake vendor:windows_x64  # Download libui.dll for Windows to vendor directory
rake vendor:windows_x86  # Download libui.dll for Windows to vendor directory

For example, If you are using a 32-bit (x86) version of Ruby on Windows, type rake vendor:windows_x86.

Or Set environment variable LIBUIDIR to specify the path to the shared library. This is especially useful on platforms where the LibUI gem does not provide shared library, such as the ARM architecture (used in devices like Raspberry Pi). You can compile C libui from source code on your platform and tell ruby LibUI where to find the shared libraries (See #46).

libui-ng

libui-ng is the successor project to libui. Rake tasks are available to build or download libui-ng shared libraries.

rake libui-ng:build[hash]  # Build libui-ng latest master
rake libui-ng:mac          # Download latest dev build for Mac to vendor directory
rake libui-ng:ubuntu_x64   # Download latest dev build for Ubuntu to vendor directory

rake install

Contributing

Would you like to add your commits to libui?

• Please feel free to send us your pull requests.
  • Small corrections, such as typo fixes, are appreciated.
• Did you find any bugs? Enter in the issues section!

I have seen many OSS projects abandoned. The main reason is that no one has the right to commit to the original repository, except the founder. Do you need commit rights to my repository? Do you want to get admin rights and take over the project? If so, please feel free to contact me @kojix2.

Acknowledgement

This project is inspired by libui-ruby.

• https://github.com/jamescook/libui-ruby

While libui-ruby uses Ruby-FFI, this gem uses Fiddle.

License

MIT License.