VRR is a vector image editor designed especially (but not only) for making illustrations of mathematical articles. Its main features are many types of geometric objects and keeping of their dependencies, cooperation with TeX, scripting in Scheme, real-size dimensions, support for a wide range of file formats (including PS, EPS, PDF, and SVG).
batchgimp is a batch processor for rendering of images. It uses a command-line interface, and supports JPEG, GIF, PNG, and PSD file formats. It accesses the GNU Image Manipulation Program (GIMP) plug-in structure to provide image processing functions. Images are processed in a batch for an entire directory. batchgimp is written in Perl and interfaces with the Scheme scripting engine provided by the GIMP.
Fluxus is a graphical live coding environment for Scheme. Fluxus reads live audio or OSC network messages which can be used as a source of animation data for real-time performances or installations. Keyboard or mouse input can also be read for simple game development, and a physics engine is included for realtime simulations of rigid body dynamics. The built in scheme code editor runs on top of the renderer, which means you can edit the scripts while they are running.
TextureOps is a set of plug-ins for the GIMP related to texture. Compositing a feathered layer on top of another layer slightly reduces the contrast in the the feathered region, noticably modifying the texture. TextureOps contains a "Sharpen Feathering" plug-in to counteract this effect. Also in TextureOps is a modified version of the standard "Make Seamless" plug-in that produces a more uniform result, based on similar principals. Finally, TextureOps provides a simple script for synthesizing a tilable texture of arbitrary size from a sample using the Sharpen Feathering plug-in.
sr-convert is a sample-rate conversion utility for WAV files. It supports a wide variety of sampling rates and can convert from any of the supported rates to any other. It runs under either x86 Linux or Windows and uses SSE instructions if they are available. Great pains have been taken to make sure that the sound quality of the conversion is excellent.
jMax is a visual programming environment for building interactive real-time musical and multimedia applications by allowing the user to interactively design dataflow circuits. The basic data types that can go through are integers, symbols, lists, etc. It is an event-driven system and has been used for MIDI processing. A second part of the system (DSP) allows a continuous signal to flow through a circuit, which is most useful for PCM sound (ie. microphone, sound files, etc.). The system is extensible by using shared libraries, you may add data processor types, data types, GUI elements, device types, and more. Data processors may also be designed as circuits and reused.
GLAME (GNU/Linux Audio Mechanics) is meant to be the GIMP of audio processing. It is designed to be a powerful, fast, stable, and easily extensible sound editor for Linux and compatible systems. It has full support for non-destructive editing including undo/redo and applying LADSPA effects. Its supported platforms are Linux, BSD, IRIX, and OS X. It uses guile and libxml, and the GNOME libs available is highly recommended. MP3 and Ogg files can be processed if libmad and libvorbisfile are installed.