gedit/docs/gedit-development-getting-started.md

gedit development - getting started

The following explanations can be improved over time, if you see something missing, a feedback is welcome.

Programming languages and paradigms

gedit is mostly written in C, with some plugins in Python. The Meson build system is used.

The code is object-oriented and event-driven. In C, it's thanks to the use of the GObject library (see next section). If you open some *.c or *.h files, you may be frightened but – don't panic – it's just some C/GObject boilerplate code, and that boilerplate can be generated by a tool. So once you've learned GObject, you will no longer be afraid ;-)

Libraries used

As every GNOME application, gedit uses the GLib, GObject and GTK libraries. To modify the gedit source code, you should be familiar with those libraries. See the GTK website and The GLib/GTK Development Platform – A Getting Started Guide.

The main "text area" in gedit is a GtkTextView widget. This widget is part of GTK. You can learn it with the GtkTextView tutorial. The tutorial is a bit old but the GtkTextView API has not changed a lot. (By the way, contributing to update the tutorial would be a useful task!).

GtkTextView provides the basis, and is extended by other libraries to add more features. See Gedit Technology.

For its plugin system, gedit uses libpeas.

Plugins may have other dependencies, for example the spell-checking plugin uses gspell.

gedit architecture

The gedit git repository contains:

• The "gedit core" in the gedit/ directory.
• The default plugins in plugins/.

There is also the gedit-plugins git repository for additional official plugins.

The gedit core provides:

• A basic text editor.
• The integration of libpeas, with an API for plugins.

There is a class diagram of gedit core in the file class-diagram.dia (but it may be outdated, see the Git log for that file).

Build/Installation

See the file build.md.

Suggestions

A good way to learn a lot of things is to write a new plugin (it can be a third-party plugin at first).

Improving the API reference of the gedit core would be useful, because some parts lack proper documentation.

A potentially easy task is to fix compilation warnings, for example when a deprecated function is used. If you encounter a runtime warning or critical message, it is also a good idea to fix it.

Note that gedit is an old piece of software. Some parts are legacy code and would benefit from some refactoring.