github.com/wjakob/nanogui) |  A minimalistic cross-platform widget library for OpenGL 3.x or higher ( [ Doc ](https://nanogui.readthedocs.io/en/latest/) )  |  |   
[ OWLNext ](http://sourceforge.net/projects/owlnext/) |  Modern update to [ OWL ](https://en.wikipedia.org/wiki/Object_Windows_Library) for writing GUI applications in standard C++ on Windows  |  |   
[ Slint ](https://slint.dev) |  A declarative GUI toolkit to build native user interfaces for desktop, embedded, and microcontrollers. ( [ Src ](https://github.com/slint-ui/slint) ), ( [ Doc ](https://slint.dev/docs/cpp) )  |  GPL 3, [ Royalty-free ](https://github.com/slint-ui/slint/blob/master/LICENSES/LicenseRef-Slint-Royalty-free-1.1.md) , or Commercial  |  cmake   
[ tiny file dialogs ](http://tinyfiledialogs.sourceforge.net) |  A set of C/C++ cross-platform file dialogs (no init, no main loop, 6 modal function calls)  |  |  header-only   
[ U++ ](https://www.ultimatepp.org) |  A cross-platform (Windows, GNU/Linux, macOS) rapid application development framework with bundled IDE. C++17 Compatible. ( [ Doc ](https://www.ultimatepp.org/www$uppweb$documentation$en-us.html) ) ( [ Src ](https://github.com/ultimatepp/ultimatepp) )  |  BSD-3-Clause  |  make   
[ WxWidgets ](https://wxwidgets.org/) |  A free and open-source cross-platform (Windows, GNU/Linux, macOS) C++ framework for writing advanced GUI applications using native controls. ( [ Doc ](https://docs.wxwidgets.org) )  |  Modified LGPL  |  cmake, make   
[ xtd ](https://gammasoft71.github.io/xtd/) |  A modern C++17/20 framework to create console, GUI and unit tests applications on Windows, macOS, Linux, iOS, and Android. ( [ Src ](https://github.com/gammasoft71/xtd) ) ( [ Doc ](https://gammasoft71.github.io/xtd/reference_guides/latest/index.html) )  |  MIT  |  cmake   
  
CopperSpice

Library  |  Description  |  License  |  Configuration   
---|---|---|---  
[ CopperSpice ](https://www.copperspice.com/) |  A set of C++ libraries used to develop cross-platform software applications. It uses modern idiomatic C++ and integrates seamlessly with the STL. CopperSpice was derived from the Qt framework. ( [ Doc ](https://www.copperspice.com/documentation-copperspice.html) ) ( [ Src ](https://github.com/copperspice/copperspice) )  |  LGPL-2.1  |  cmake   
[ CsSignal ](https://github.com/copperspice/cs_signal) |  A standalone C++ thread aware signal/slot library  |  LGPL-2.1  |  cmake   
[ CsString ](https://github.com/copperspice/cs_string) |  A standalone C++ Unicode aware string library  |  LGPL-2.1  |  cmake   
[ libGuarded ](https://github.com/copperspice/libguarded) |  A standalone C++ multithreading library for managing access to shared data  |  LGPL-2.1  |  cmake   
  
GTK+

Library  |  Description  |  License  |  Configuration   
---|---|---|---  
[ evince ](https://wiki.gnome.org/Apps/Evince) |  |  |   
[ flowcanvas ](https://drobilla.net/software/flowcanvas.html) |  |  |   
[ glibmm ](https://www.gtkmm.org/) |  |  |   
[ goocanvasmm ](https://live.gnome.org/GooCanvas) |  |  |   
[ gtkmm ](https://gtkmm.org) |  A cross-platform C++ interface for the [ GTK+ ](https://www.gtk.org/) GUI library.  |  [ LGPL ](https://gtkmm.org/en/license.shtml) |   
[ libglademm ](https://www.gtkmm.org/) |  |  |   
[ libgnomecanvasmm ](https://www.gtkmm.org/) |  |  |   
[ webkitgtk ](https://webkitgtk.org/) |  |  |   
  
Qt

Library  |  Description  |  License  |  Configuration   
---|---|---|---  
[ libdbusmenu-qt ](https://launchpad.net/libdbusmenu-qt) |  A small library designed to make sharing and displaying of menu structures over DBus simple and easy to use. It works for both QT and GTK+ and makes building menus simple.  |  |   
[ Qt ](https://qt.io/) |  ( [ Doc ](https://doc.qt.io/) ) ( [ Src ](https://qt.io/download) )  |  |   
[ QuickQanava ](https://github.com/cneben/QuickQanava) |  A C++14 network/graph visualization library / Qt node editor.  |  BSD 2.0  |  cmake   
[ qwt5 ](http://qwt.sourceforge.net) |  Qt Widgets for