libui-ng: a portable GUI library for C

Fork of andlabs/libui. This README is being written.

About

Simple and portable (but not inflexible) GUI library in C that uses the native GUI technologies of each platform it supports.

Status

libui-ng is currently mid-alpha software.

See CHANGELOG.md

Old announcements can be found in the news.md file.

Runtime Requirements

Windows: Windows Vista SP2 with Platform Update or newer
Unix: GTK+ 3.10 or newer
Mac OS X: OS X 10.8 or newer

Build Requirements

All platforms:
- Meson 0.48.0 or newer
- Any of Meson's backends; this section assumes you are using Ninja, but there is no reason the other backends shouldn't work.
Windows: either
- Microsoft Visual Studio 2013 or newer (2013 is needed for va_copy()) — you can build either a static or a shared library
- MinGW-w64 (other flavors of MinGW may not work) — you can only build a static library; shared library support will be re-added once the following features come in:
  - Isolation awareness, which is how you get themed controls from a DLL without needing a manifest
Unix: nothing else specific
Mac OS X: nothing else specific, so long as you can build Cocoa programs

Building

libui uses only the standard Meson build options, so a libui build can be set up just like any other:

$ # you must be in the top-level libui directory, otherwise this won't work
$ meson setup build [options]
$ ninja -C build

Once this completes, everything will be under build/meson-out/. (Note that unlike the previous build processes, everything is built by default, including tests and examples.)

The most important options are:

--buildtype=(debug|release|...) controls the type of build made; the default is debug. For a full list of valid values, consult the Meson documentation.
--default-library=(shared|static) controls whether libui is built as a shared library or a static library; the default is shared. You currently cannot specify both, as the build process changes depending on the target type (though I am willing to look into changing things if at all possible).
-Db_sanitize=which allows enabling the chosen sanitizer on a system that supports sanitizers. The list of supported values is in the Meson documentation.
--backend=backend allows using the specified backend for builds instead of ninja (the default). A list of supported values is in the Meson documentation.

Most other built-in options will work, though keep in mind there are a handful of options that cannot be overridden because libui depends on them holding a specific value; if you do override these, though, libui will warn you when you run meson.

The Meson website and documentation has more in-depth usage instructions.

For the sake of completeness, I should note that the default value of --layout is flat, not the usual mirror. This is done both to make creating the release archives easier as well as to reduce the chance that shared library builds will fail to start on Windows because the DLL is in another directory. You can always specify this manually if you want.

Backends other than ninja should work, but are untested by me.

Installation

Meson also supports installing from source; if you use Ninja, just do

$ ninja -C build install

When running meson, the --prefix option will set the installation prefix. The Meson documentation has more information, and even lists more fine-grained options that you can use to control the installation.

Arch Linux

Can be built from AUR: https://aur.archlinux.org/packages/libui-git/

Documentation

Needs to be written. Consult ui.h and the examples for details for now.

Language Bindings

libui was originally written as part of my package ui for Go. Now that libui is separate, package ui has become a binding to libui. As such, package ui is the only official binding.

Other people have made bindings to other languages:

Language	Bindings
C++	libui-cpp, cpp-libui-qtlike
C# / .NET Framework	LibUI.Binding
C# / .NET Core	DevZH.UI, SharpUI, SimplexiDev.UI
CHICKEN Scheme	wasamasa/libui
Common Lisp	jinwoo/cl-ui
Crystal	libui.cr, hedron
D	DerelictLibui (flat API), libuid (object-oriented)
Euphoria	libui-euphoria
Harbour	hbui
Haskell	haskell-libui
Janet	JanetUI
JavaScript/Node.js	libui-node, libui.js (merged into libui-node?), proton-native, vuido
Julia	Libui.jl
Kotlin	kotlin-libui
Lua	libuilua, libui-lua, lui, lui
Nim	ui
Perl6	perl6-libui
PHP	ui
Python	pylibui
Ruby	libui-ruby, LibUI, Glimmer DSL for LibUI
Rust	libui-rs
Scala	scalaui
Swift	libui-swift

Frequently Asked Questions

Why does my program start in the background on OS X if I run from the command line?

OS X normally does not start program executables directly; instead, it uses Launch Services to coordinate the launching of the program between the various parts of the system and the loading of info from an .app bundle. One of these coordination tasks is responsible for bringing a newly launched app into the foreground. This is called "activation".

When you run a binary directly from the Terminal, however, you are running it directly, not through Launch Services. Therefore, the program starts in the background, because no one told it to activate! Now, it turns out there is an API that we can use to force our app to be activated. But if we use it, then we'd be trampling over Launch Services, which already knows whether it should activate or not. Therefore, libui does not step over Launch Services, at the cost of requiring an extra user step if running directly from the command line.