Crimson Editor is a freeware text editor. It is typically used as a source code editor, and HTML editor, for Microsoft Windows. The author was Ingyu Kang.
The last formal release was in September 2004. On December 30, 2006, Ingyu Kang posted a message announcing Crimson Editor as an open source project. Crimson Editor is now being maintained and modified by the members of the Emerald Editor community.
Crimson Editor features Windows shell integration, tabbed document interface, syntax highlighting, multiple undo/redo, column mode editing, bracket matching, auto-indentation, spell checking, direct editing of text files in FTP and the integration with compilers. Unicode (although only for the characters within the default character set of Windows) and various newlines are supported. Crimson Editor also supports the use of macros. The built-in calculator can evaluate simple expressions. Basic mathematics functions, and date functions are also available.
Crimson Editor has been extensively reviewed and well received. It has been described as a very good editor and pseudo-IDE interface for programmers to use. It has been highlighted that it has a good set of features, syntax highlighting for lots of formats, and includes integrated FTP. However there are some memory issues with several (full project) files, and it sometimes crashes.
Emerald Editor is a text editor, that is under development, that has been substantially influenced by Crimson Editor. Available under the GNU General Public License, it will be an open-source, multi-purpose, functional text editor.