crypt++.el is a package of Lisp functions that recognize automatically encrypted and encoded (i.e., compressed) files when they are first visited or written. The BUFFER corresponding to the file is decoded and/or decrypted before it is presented to the user. The file itself is unchanged on the disk. When the buffer is subsequently saved to disk, a hook function re-encodes the buffer before the actual disk write takes place.
ctGUI is the window system abstraction and associated widget sets in the Coral Tree Library Set. The window system abstraction currently supports X/OpenGL, X/Xlib, Win32/OpenGL, and Win32/GDI (window & event system/drawing mechanism). ctGUI (aka LEWDS and EW/WDS/IWS) provides yet another approach in addition to the approaches taken by Qt, gtk, MFC, etc.
cthumb allows you to create Web albums of digital pictures with thumbnails, captions, and several different views of the collection, including (optionally) several languages and resolutions. An album is composed of a series of pages, each composed of a collection of pictures. You can have several annotations per picture, and can customize almost everything in the way the albums look on the screen.
ctm.pl is a Perl script which generates Apache type maps for use with mod_negotiation. Useful if you have a lot of images available in different formats you need type maps for, especially if you don't want to use MultiViews to decide which of them will be sent back to the requesting browser.
CwMtx is a library written in C++ that provides the matrix and vector operations that are used extensively in engineering and science problems. A special feature of this library is the quaternion class which implements quaternion math. Quaternions are very useful for attitude determination in 3D space because they do not suffer from singularities. Furthermore, successive rotations and transformations of vectors can be accomplished by simple quaternion multiplication. Attitude dynamics can be expressed in a very compact form using quaternions