wxWidgets

What is wxWidgets ? (formerly known as wxWindows)

wxWidgets gives you a single, easy-to-use API for writing GUI applications on multiple platforms. 

Link with the appropriate library for your platform (Windows/Unix/Mac) and compiler (almost any popular C++ compiler), and your application will adopt the look and feel appropriate to that platform. 

On top of great GUI functionality, wxWidgets gives you: online help, network programming, streams, clipboard and drag and drop, multithreading, image loading and saving in a variety of popular formats, database support, HTML viewing and printing, and much much more.

wxWidgets is a set of libraries that allows C++ applications to compile and run on several different types of computer, with minimal source code changes. There is one library per supported GUI (such as Windows, GTK+, Motif, and Mac). As well as providing a common API (Application Programming Interface) for GUI functionality, it provides functionality for accessing some commonly-used operating system facilities, from copying and deleting files to socket and thread support. wxWidgets is a 'framework' in the sense that it provides a lot of built-in functionality, which the application can use or replace as required, thus saving a great deal of coding effort. Basic data structures such as strings, arrays, linked lists and hash tables are also supported.

KOAN is 'wxWidgets evangelist' since year 2000 and provides fast and reliable technical support and consulting.

KOAN contributes to various Open Source projects and the wxWidgets cross platform library as first italian developer partner

This is a link to wxWidgets website