GNU TeXmacs is a free wysiwyw (what you see is what you want) editing platform with special features for scientists. The software aims to provide a unified and user friendly framework for editing structured documents with different types of content: text, mathematics, graphics, interactive content. TeXmacs can also be used as an interface to many external systems for computer algebra, numerical analysis, and statistics. New presentation styles can be written by the user and new features can be added to the editor using Scheme.
Univert is a Universal Unicode Converter, at least as universal as the Unicode implementation in Tcl 8.1 or later can manage on your computer. Univert will convert interchangably between the following formats: native Tcl unicode, hex bytes or words separated by spaces, decimal bytes or words separated by spaces, HTML entities, UTF-8/URL encoding, quoted printable with whatever the current encoding is, and C string with whatever the current encoding is.
libtholoura is a text-image distortion library, which is useful for sites that want to ensure that a human (and not a bot) is viewing pages. It is optimized to produce images of strings distorted in a way that makes it impossible for an OCR to read, but humans can. The library takes a string (preferably ASCII) string and is able to dynamically produce PNG indexed images. The distortion filters are external plugins.