wxWidgets

Home: http://wxwidgets.org/
Media: https://en.wikipedia.org/wiki/WxWidgets
State: mature
Download: http://wxwidgets.org/downloads/
Keyword: library, gui toolkit
Code repository: https://github.com/wxWidgets/wxWidgets.git (@created 2011, @stars 3444, @forks 1190)
Code language: C++, Objective-C
Code license: Custom

C++ library that lets developers create applications for Windows, Mac OS X, Linux and other platforms.

Building