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.