The OpenGL Extension Wrangler Library is a simple tool that helps C/C++ developers initialize extensions and write portable applications. GLEW currently supports a variety of operating systems, including Windows, Linux, Darwin, Irix, and Solaris.
A Free Experimental System for Image Processing
ImLab is a free open source graphical application for Scientific Image Processing that runs in Windows, Linux and many other UNIX systems. It supports multiple windows, data types including 32 bit integers, 32 bit real numbers and complex numbers.