Rendera is an open-source painting program. The tools, shapes, blenders, edge-wrapping, and cloning may all be combined to suit a particular need. The program is different in that brushstrokes are computed and rendered after being drawn. Some uses for Rendera include photo restoration, colorizing, making seamless tiles, etc.
Currently being rewritten from scratch using C++/FLTK. The new code base is easier to deal with and will allow for more platforms (Linux for now, Windows support coming soon).
Latest Source Code on GitHub
Rendera on SourceForge Page