The Graphics Transformation Languages is a set of libraries for using and
integrating transformation algorithms (such as filter or color conversion) in
graphics applications.
The goal is to provide the tools, languages and libraries to create generic
transformation for graphics. Those transformations could then be used by
different programs (Krita, The Gimp, CinePaint, gegl...).

Currently the focus is on developing two languages, designed for two different
implementations.
- OpenCTL which is a GPL compatible of the Color Transformation Language, this
  language is dedicated at transforming the value of a single pixel (for
  instance brightness adjustement or desaturate). CTL is designed to be part of
  the Color Management process.
- OpenShiva is inspired by Adobe's Hydra language from the AIF Toolkit, Shiva
  is a language that apply a kernel-like transformations on an image, that means
  it works using more than one pixel.

WWW: http://opengtl.org