Version Qt -Free and Open-Source Widget Toolkit 

Qt is a free and open-source widget toolkit for creating graphical user interfaces as well as cross-platform applications that run on various software and hardware platforms with little or no change in the underlying codebase while still being a native application with native capabilities and speed (Wikipedia). Qt gives everything you need for your entire software development life cycle. Qt is the fastest and smartest way to produce industry-leading software that users love. We use Qt for the SmartTomo user interface and the Qt development tools for the whole product development process.