The richtext mode of jedit is intended for editing text with fancier formatting than is possible in plain ASCII, including multiple fonts and colours and underlining. By default, jedit opens files whose names end in .jrt in richtext mode; you'll probably find it most convenient to give such files names ending in .jrt.
The ability to work with rich text is not unique to richtext mode; it's built into jedit and described under Working with Fonts and Colours in the jedit documentation. (However, most modes don't display the `Format' menu by default.)
This document describes the richext mode available with version 3.6/3.0 of jedit.
The Format Menu
The main visible difference between richtext mode and plain mode is that the `Format' menu is available by default. (Of course, you can change which menus are available with the Mode¡Specific Preferences panel, as with any mode.)
Saving and Loading Files
In richtext mode, files are saved in a special format. The first part of the file contains the actual text of the file, and should be reasonably legible if you look directly at the file contents (with another editor, for example). This is followed by information about stretches of text with various styles - e.g., where all the sequences of boldface text start and end, and by information about special positions in the file, such as where the insert point is or where the last search started from. (This last information isn't normally used.)
(This format is implemented by the j:tag:archive_text_widget and j:tag:restore_text_widget procedures in the jtexttags.tcl library, which see for more information.)
