This is a text (into image) distortion library. It is useful if you want to create a site which wants to keep out the various bots and ensure that a human is reading your page. The library is written in C and is based on various distortion modules, completely independent of the actual library (and easily programmable).
The program is under the GNU GPL and you can download it here.
A few test pictures follow. Note that in these are random generated images with 8 digit numbers. The library itself is able to render any desired text or random text with numerals or lower and upper case characters.
A live demonstration of the library can be seen here