The core aims of OpenFX were established early on, these are…

• to develop a standard for writing visual effects plug-ins,
• to develop that standard with a broad consensus within the industry,
• have that standard be vendor and operating system neutral,
• have that standard be sufficiently flexible that it supports a wide range of visual effects systems, from editors to compositors.

Subsidiary aims are,

• have the standard be expandable to other areas in the future, for example sound plug-ins or image i/o plug-ins,
• have any expansion of the standard be done in such a manner so that hosts can easily support plug-ins using differerent versions of the API,
• have plug-ins written to the standard be tunable to the host system they are running on,
• allow hosts to provide extra custom functionality to plugins that wish to use it.

Home Page: http://openfx.sourceforge.net/
Project Page: http://sourceforge.net/projects/openfx/
Language: c++
Platform: Linux, OS X, Windows
License: BSD
Sponsor: The Foundry, Autodesk, Gen-Arts, FilmLight, Assimilate, Re-Vision Effects

Home Page: http://danbethell.github.com/rmanconnect/
Project Page: http://github.com/danbethell/rmanconnect
License: New BSD

Imagemagick provides a rich feature set including:

• Format conversion: convert an image from one format to another (e.g. PNG to JPEG).
• Transform: resize, rotate, crop, flip or trim an image.
• Transparency: render portions of an image invisible.
• Draw: add shapes or text to an image.
• Decorate: add a border or frame to an image.
• Special effects: blur, sharpen, threshold, or tint an image.
• Animation: create a GIF animation sequence from a group of images.
• Text & comments: insert descriptive or artistic text in an image.
• Image identification: describe the format and properties of an image.
• Composite: overlap one image over another.
• Montage: juxtapose image thumbnails on an image canvas.
• Motion picture support: read and write the common image formats used in digital film work.
• Image calculator: apply a mathematical expression to an image or image channels.
• Discrete Fourier transform: implements the forward and inverse DFT.
• High dynamic-range images: accurately represent the wide range of intensity levels found in real scenes ranging from the brightest direct sunlight to the deepest darkest shadows.
• Encipher or decipher an image: convert ordinary images into unintelligible gibberish and back again.
• Virtual pixel support: convenient access to pixels outside the image region.
• Large image support: read, process, or write mega-, giga-, or tera-pixel image sizes.
• Threads of execution support: ImageMagick is thread safe and most internal algorithms are OpenMP-enabled to take advantage of speed-ups offered by the dual and quad-core processor technologies.
• Heterogeneous distributed processing: certain algorithms are OpenCL-enabled to take advantage of speed-ups offered by executing in concert across heterogeneous platforms consisting of CPUs, GPUs, and other processors.

Home Page: http://www.imagemagick.org/
Language: C with API's provided for C++ and Perl
Platform: Windows, Linux, OSX
License: Custom open source license that requires attribution. Free for commercial use. GPL compatible.

pyshake is being developed by Rising Sun Pictures.

Home Page: http://open.rsp.com.au
Project Page: http://open.rsp.com.au/projects/pyshake
Language: C++
Platform: Linux, Windows, OS X
License: LGPLv2.1.
Sponsor: Rising Sun Pictures