The Code Format plugin allows simple and precise formatting of C, C++ and Objective-C source code using the excellent utility clang-format provided as part of the ClangTools.

• Accurate lexical code formatting using Clang frontend.
• Runs clang-format as an external process so you can swap out and upgrade versions at will without touching the plugin.
• Auto-formatting; never worry about formatting again, let the plugin do all the work!
• Can format current line, current selection, current document, or auto-format the entire document based on specified trigger characters.

Activate the plugin using Geany's Plugin Manager dialog. Once activated it will place a new Code Format item in the Tools menu inside the main menu. You can access basic functionality from here. The items and submenu's will automatically become enabled or disabled as certain features cannot be used (ex. trying to format with no open documents or documents with unsupported filetypes).

There are two keybindings available, one to format the current selection (or current line if there is no selection), the other to format the entire document. You can set the keybindings through Geany's main Preferences dialog in the Keybindings tab.

The preferences are broken into two parts. The first is a regular .conf file containing your settings for the Code Format plugin itself, like where to find the clang-format utility, or whether auto-formatting is enabled. The second type of preferences are those sepcified in YAML files and are read by the clang-format utility to control how the code is formatted. This section discusses the former.

The user preferences are stored in a file named code-format.conf found in under the Geany configuration directory inside the plugins directory. The project-specific settings are stored inside the actual Geany project file (usally ends with .geany).

If a project is open, the project-specific preferences take effect and can be changed using the Project Preferences dialog accessible through Geany's Project menu. If no project is opened, then the user preferences are used and can be changed using the Plugin Preferences dialog accessible through Geany's Edit menu. If you change the user preferences while a project is open, the changes made won't take effect until there is no project open.

In the configuration files, Code Format settings are stored in the [code-format] group.

This setting specifies the path to the clang-format utility that is part of ClangTools. If the executable is found in the PATH environment variable, you can just put clang-format otherwise, you can choose the full path to the binary. When a valid executable file is found, an "OK" icon will appear in the text box, otherwise an "error" icon will appear. It only means that the file is found and is executable, not that it's actually clang-format.

In the configuration file, this setting is known as clang-format-path.

This setting controls whether to use one of the preset code formatting styles available from clang-format or whether to use a Custom .clang-format file to control the code formatting style. If you select one of the presets, you can click on the Create button to open a new YAML document in Geany containing the code formatting settings based on the selected item that you can tailor to suit your specific code formatting style.

In the configuration file, this setting is known as style and can be (at present) one of llvm, google, chromium, mozilla or custom.

This setting controls whether the active document will be formatted just before Geany saves it. This is especially useful if you don't like to enable the auto-formatting option but still want mostly-automatic formatting of the code.

In the configuration file, this setting is known as format-on-save.

This setting controls whether the current document is formatted automatically when one of a specific set of trigger characters are typed. Even though it is not on by default, it is recommended that you use this feature, and only turn if off if you find it annoying or it gets too slow on large documents.

In the configuration file, this setting is known as auto-format.

When auto-format is enabled, this setting controls the characters which when typed will cause the document to be re-formatted. The default set ")}];" seems to work well but you might like to customize these a bit. You probably don't want to use "\n" (newline) or similar.

In the configuration file, this setting is known as auto-format-trigger-chars.

ClangFormat is part of the ClangTools set of utilities. You must install the clang-format utility in order to use the Code Format plugin for Geany. You can configure which clang-format executable gets used in the Preferences (see above). It is HIGHLY recommended that you read the documentation for clang-format (at the above link) before using the Code Format plugin, in order to have any clue how it works.

It's important to note that various features documented or available through the user interface may not actually be supported by your version of clang-format. It is recommended to always use the latest version although it seems to handle unknown options and such gracefully.

If you're using one of the preset code formatting styles (see Preferences), you basically don't have to configure anything for clang-format. The presets are equivalent to running:

$ clang-format -style=<NAME_OF_STYLE> ...

Where <NAME_OF_STYLE> is not equal to file.

If you're using a custom .clang-format file, you should configure it as per ClangFormat's documentation. It's a YAML file with readable names and you should be able to figure it out while referencing the ClangFormat documentation (at the above link). The custom configuration is equivalent to running:

$ clang-format -style=file ...

The special name file tells clang-format to read .clang-format files instead of using a preset.

To get started, you can base your custom configuration on one of the presets by using the "Create" button in the preferences dialog with the desired preset selected in the list (see Preferences). The "Create" button is equivalent to running:

$ clang-format -style=<SELECTED_PRESET> -dump-config

Where <SELECTED_PRESET> is the preset chosen in the Style list when the button is pressed. The output of the command is placed into a new unsaved document named .clang-format. You should then save it in a directory (see below) and customize it according to your needs.

The .clang-format file should be saved at or above the document(s) you want formatting to work for. For example you can put it straight into the source directory or you can put it at the root of your project directory and it will affect all subdirectories (unless a certain subdirectory has a .clang-format file as well). Because of this functionality, it is required that a document has been saved on disk before so that the plugin can determine in which directory to start looking for .clang-format files. If you try and use the plugin on a new, never before saved document, the plugin simply won't function and it will print some message to Geany's standard output.

The Code Format plugin was written by and is maintained by Matthew Brush <matt(at)geany(dot)org>. You can report any issues on the Github Issues page (TODO link) or provide any improvement by making a Pull Request on Github.