U++ is a C++ cross-platform rapid application development suite focused on programmers' productivity without sacrificing runtime performance. Based on strictly deterministic design, it provides a viable alternative to garbage-collected platforms, even for business logic oriented problems.
DEMUX Framework enables Java developers to build modular, cross-platform applications which can run on desktop, Web, and mobile and embedded devices. It is based on OSGI and supports creating JavaFX desktop applications, mobiles apps (Android, iOS, Windows), and Web applications.
wxPython is a Python extension module that wraps the wxWidgets cross-platform GUI library and provides an alternative to Tkinter and PythonWin. It attempts to mirror the class hierarchy of wxWidgets as closely as possible and is very versatile. It can be used to create standalone GUI applications or can be used in situations in which Python is embedded in a wxWidgets C++ application as an internal scripting or macro language. The currently supported GUIs are Win32, GTK/X-Windows, and Mac OS X.
Coin is an implementation of Open Inventor. Open Inventor is the de facto standard API for retained-mode 3D graphics programming. Open Inventor has a highly extensible design, and has been designed to allow for rapid development of highly interactive 3D graphics applications in the fields of CAD, engineering, scientific computing, simulation, VRML, and visualization.
The C++ Portable Types Library (PTypes) is a simple alternative to the STL that includes multithreading and networking. It defines dynamic strings, character sets, variants, lists and other basic data types along with threads, synchronization primitives and IP sockets. It is portable across modern Unix and Windows systems and includes a sample HTTP daemon showing the full power of the library.
The Ecere SDK is a cross-platform toolkit for building software applications. It currently runs on Windows, Linux, Mac OS X (through X11), FreeBSD, and the Android OS. It should run on other Unix platforms with minor testing/tweaking. With the Ecere SDK, you can develop applications once and deploy them on all supported platforms alongside a lightweight runtime environment. It introduces eC, an object oriented language derived from and fully compatible with C, compromising neither runtime performance nor ease of use. A built-in 3D engine supporting both Direct3D and OpenGL is fully integrated.
OpenGUI is a high-level multi-platform, thread-safe C/C++ windowing and graphics library built upon a fast, low-level graphics kernel. It provides 2D drawing primitives and an event-driven windowing API for easy application development. The benefit of this library is speed, power, and a well-designed API with a narrow learning curve. It supports the BMP, JPG, TGA, PNG, TIFF, and PCX image file formats, color gradients, and TTF fonts. There is also basic XML file support and a smart persistence wrapper. OpenGUI supports the keyboard and mouse as event sources, the Linux framebuffer, SVGAlib, and XFree86/DGA2 (HW accelerated) as drawing backends, Mesa3D under Linux, and 8, 15, 16, and 32-bpp color modes.