## XfcePanelPlugin XfcePanelPlugin — Panel plugin interface. |

## Synopsis

    #include <libxfce4panel/libxfce4panel.h>

                        XfcePanelPlugin;
    void                (*XfcePanelPluginFunc)              (XfcePanelPlugin *plugin);
    gboolean            (*XfcePanelPluginCheck)             (GdkScreen *screen);
    gboolean            (*XfcePanelPluginPreInit)           (int argc,
                                                             char **argv);
    gchar *             xfce_panel_plugin_get_name          (XfcePanelPlugin *plugin);
    gchar *             xfce_panel_plugin_get_id            (XfcePanelPlugin *plugin);
    gchar *             xfce_panel_plugin_get_display_name  (XfcePanelPlugin *plugin);
    gint                xfce_panel_plugin_get_size          (XfcePanelPlugin *plugin);
    XfceScreenPosition  xfce_panel_plugin_get_screen_position
                                                            (XfcePanelPlugin *plugin);
    void                xfce_panel_plugin_set_expand        (XfcePanelPlugin *plugin,
                                                             gboolean expand);
    gboolean            xfce_panel_plugin_get_expand        (XfcePanelPlugin *plugin);
    GtkOrientation      xfce_panel_plugin_get_orientation   (XfcePanelPlugin *plugin);
    void                xfce_panel_plugin_add_action_widget (XfcePanelPlugin *plugin,
                                                             GtkWidget *widget);
    void                xfce_panel_plugin_menu_insert_item  (XfcePanelPlugin *plugin,
                                                             GtkMenuItem *item);
    void                xfce_panel_plugin_menu_show_about   (XfcePanelPlugin *plugin);
    void                xfce_panel_plugin_menu_show_configure
                                                            (XfcePanelPlugin *plugin);
    void                xfce_panel_plugin_block_menu        (XfcePanelPlugin *plugin);
    void                xfce_panel_plugin_unblock_menu      (XfcePanelPlugin *plugin);
    void                xfce_panel_plugin_register_menu     (XfcePanelPlugin *plugin,
                                                             GtkMenu *menu);
    gchar *             xfce_panel_plugin_lookup_rc_file    (XfcePanelPlugin *plugin);
    gchar *             xfce_panel_plugin_save_location     (XfcePanelPlugin *plugin,
                                                             gboolean create);
    void                xfce_panel_plugin_focus_widget      (XfcePanelPlugin *plugin,
                                                             GtkWidget *widget);
    void                xfce_panel_plugin_set_panel_hidden  (XfcePanelPlugin *plugin,
                                                             gboolean hidden);

## Object Hierarchy

      GInterface
       +----XfcePanelPlugin

## Prerequisites

XfcePanelPlugin requires GtkContainer.

## Known Implementations

XfcePanelPlugin is implemented by XfceExternalPanelPlugin and XfceInternalPanelPlugin.

## Properties

      "display-name"             gchar*                : Read
      "expand"                   gboolean              : Read / Write
      "id"                       gchar*                : Read
      "name"                     gchar*                : Read
      "screen-position"          XfceScreenPosition    : Read
      "size"                     gint                  : Read

## Signals

      "about"                                          : Run Last / No Recursion / No Hooks
      "configure-plugin"                               : Run Last / No Recursion / No Hooks
      "free-data"                                      : Run Last / No Recursion / No Hooks
      "orientation-changed"                            : Run Last / No Recursion / No Hooks
      "save"                                           : Run Last / No Recursion / No Hooks
      "screen-position-changed"                        : Run Last / No Recursion / No Hooks
      "size-changed"                                   : Run Last / No Recursion / No Hooks

## Description

The interface implemented by both internal and external plugins. Plugin writers may use the functions described below to interact with the plugin widget.

## Details

### XfcePanelPlugin

    typedef struct _XfcePanelPlugin XfcePanelPlugin;

The XfcePanelPlugin is a purely virtual object to describe an instance of a widget implementing the panel plugin interface.

### XfcePanelPluginFunc ()

    void                (*XfcePanelPluginFunc)              (XfcePanelPlugin *plugin);

Callback function to create the plugin contents. It should be given as the argument to the registration macros.

See also: `XFCE_PANEL_PLUGIN_REGISTER_EXTERNAL()` and `XFCE_PANEL_PLUGIN_REGISTER_INTERNAL()`

`plugin` : | The XfcePanelPlugin

### XfcePanelPluginCheck ()

    gboolean            (*XfcePanelPluginCheck)             (GdkScreen *screen);

Callback function that is run before creating a plugin. It should return `FALSE` if the plugin is not available for whatever reason. The function can be given as argument to one of the registration macros.

`screen` : | the GdkScreen the panel is running on
Returns : | `TRUE` if the plugin can be started, `FALSE` otherwise. See also: `XFCE_PANEL_PLUGIN_REGISTER_EXTERNAL_WITH_CHECK()`, `XFCE_PANEL_PLUGIN_REGISTER_INTERNAL_WITH_CHECK()` and `XFCE_PANEL_PLUGIN_REGISTER_EXTERNAL_FULL()`

### XfcePanelPluginPreInit ()

    gboolean            (*XfcePanelPluginPreInit)           (int argc,
                                                             char **argv);

Callback function that is run in an external plugin before `gtk_init()`. It should return `FALSE` if the plugin is not available for whatever reason. The function can be given as argument to one of the registration macros.

The main purpose of this callback is to allow multithreaded plugins to call `g_thread_init()`.

`argc` : | number of arguments to the plugin
`argv` : | argument array
Returns : | `TRUE` on success, `FALSE` otherwise. See also: `XFCE_PANEL_PLUGIN_REGISTER_EXTERNAL_FULL()`

Since 4.5

### xfce_panel_plugin_get_name ()

    gchar *             xfce_panel_plugin_get_name          (XfcePanelPlugin *plugin);

The plugin name identifies a plugin type and therefore must be unique.

`plugin` : | a XfcePanelPlugin
Returns : | the plugin name.

### xfce_panel_plugin_get_id ()

    gchar *             xfce_panel_plugin_get_id            (XfcePanelPlugin *plugin);

The plugin id is a unique identifier string that is given to every instance of a panel plugin. The returned string must be free using `g_free()`.

`plugin` : | a XfcePanelPlugin
Returns : | the plugin id.

### xfce_panel_plugin_get_display_name ()

    gchar *             xfce_panel_plugin_get_display_name  (XfcePanelPlugin *plugin);

The display name is the (translated) plugin name that can be used in a user interface, e.g. a dialog or a menu.

`plugin` : | a XfcePanelPlugin
Returns : | the display name of `plugin`.

### xfce_panel_plugin_get_size ()

    gint                xfce_panel_plugin_get_size          (XfcePanelPlugin *plugin);

The size of the panel that the plugin is part of.

`plugin` : | a XfcePanelPlugin
Returns : | the current panel size.

### xfce_panel_plugin_get_screen_position ()

    XfceScreenPosition  xfce_panel_plugin_get_screen_position
                                                            (XfcePanelPlugin *plugin);

The XfceScreenPosition of the panel that the plugin is part of.

`plugin` : | a XfcePanelPlugin
Returns : | the current XfceScreenPosition of the panel.

### xfce_panel_plugin_set_expand ()

    void                xfce_panel_plugin_set_expand        (XfcePanelPlugin *plugin,
                                                             gboolean expand);

Sets whether to expand the plugin when the width of the panel increases.

`plugin` : | a XfcePanelPlugin
`expand` : | whether to expand the plugin

### xfce_panel_plugin_get_expand ()

    gboolean            xfce_panel_plugin_get_expand        (XfcePanelPlugin *plugin);

Return if this plugin will expand when the panel width increases.

`plugin` : | a XfcePanelPlugin
Returns : | `TRUE` when it will expand.

### xfce_panel_plugin_get_orientation ()

    GtkOrientation      xfce_panel_plugin_get_orientation   (XfcePanelPlugin *plugin);

Return the GtkOrientation of the panel that the plugin is part of.

`plugin` : | a XfcePanelPlugin
Returns : | the current GtkOrientation of the panel.

### xfce_panel_plugin_add_action_widget ()

    void                xfce_panel_plugin_add_action_widget (XfcePanelPlugin *plugin,
                                                             GtkWidget *widget);

Attach the plugin menu to this widget. Plugin writers should call this for every widget that can receive mouse events. If you forget to call this the plugin will not have a right-click menu and the user won't be able to remove it.

`plugin` : | a XfcePanelPlugin
`widget` : | a GtkWidget that receives mouse events

### xfce_panel_plugin_menu_insert_item ()

    void                xfce_panel_plugin_menu_insert_item  (XfcePanelPlugin *plugin,
                                                             GtkMenuItem *item);

Insert custom menu item.

`plugin` : | a XfcePanelPlugin
`item` : | the menu item to add

### xfce_panel_plugin_menu_show_about ()

    void                xfce_panel_plugin_menu_show_about   (XfcePanelPlugin *plugin);

Show the 'About' item in the menu. Clicking on the menu item will emit the "about" signal.

`plugin` : | a XfcePanelPlugin

### xfce_panel_plugin_menu_show_configure ()

    void                xfce_panel_plugin_menu_show_configure
                                                            (XfcePanelPlugin *plugin);

Show the 'Configure' item in the menu. Clicking on the menu item will emit the "configure-plugin" signal.

`plugin` : | a XfcePanelPlugin

### xfce_panel_plugin_block_menu ()

    void                xfce_panel_plugin_block_menu        (XfcePanelPlugin *plugin);

Temporarily block the menu from being shown. This can be used by plugin writers when the configuration dialog is active.

See also: `xfce_panel_plugin_unblock_menu()`

`plugin` : | a XfcePanelPlugin

### xfce_panel_plugin_unblock_menu ()

    void                xfce_panel_plugin_unblock_menu      (XfcePanelPlugin *plugin);

Don't block the menu from being shown.

See also: `xfce_panel_plugin_block_menu()`

`plugin` : | a XfcePanelPlugin

### xfce_panel_plugin_register_menu ()

    void                xfce_panel_plugin_register_menu     (XfcePanelPlugin *plugin,
                                                             GtkMenu *menu);

Register an open menu. This will make sure the panel will properly handle its autohide behaviour. You have to call this function every time the menu is opened (e.g. using `gtk_popup_menu()`).

If you want to open the menu aligned to the side of the panel (and the plugin), you should use `xfce_panel_plugin_position_menu()` as GtkMenuPositionFunc. This callback function will take care of calling `xfce_panel_plugin_register_menu()` as well.

See also: `xfce_panel_plugin_position_menu()`.

`plugin` : | a XfcePanelPlugin
`menu` : | a GtkMenu that will be opened

### xfce_panel_plugin_lookup_rc_file ()

    gchar *             xfce_panel_plugin_lookup_rc_file    (XfcePanelPlugin *plugin);

Looks up unique filename associated with `plugin` in standard configuration locations. Only use this function when you want the read location of the configuration file, since the path might point to a not writable file (for example the default- or kiosk-configuration).

See also: `xfce_panel_plugin_save_location()` and #`xfce_resource_lookup()`

`plugin` : | a XfcePanelPlugin
Returns : | path to configuration file or `NULL` if none was found. The returned string must be freed using `g_free()`.

### xfce_panel_plugin_save_location ()

    gchar *             xfce_panel_plugin_save_location     (XfcePanelPlugin *plugin,
                                                             gboolean create);

Returns the path that can be used to store configuration information. Don't use this function when you want to read the configuration file, then use xfce_panel_plugin_lookup_rc_file.

See also `xfce_panel_plugin_lookup_rc_file()` and #`xfce_resource_save_location()`.

`plugin` : | a XfcePanelPlugin
`create` : | whether the file should be created
Returns : | path to configuration file or `NULL` is the file could not be created. The returned string must be freed using `g_free()`.

### xfce_panel_plugin_focus_widget ()

    void                xfce_panel_plugin_focus_widget      (XfcePanelPlugin *plugin,
                                                             GtkWidget *widget);

Grab the focus on `widget`. Asks the panel to allow focus on its items and set the focus to the requested widget.

`plugin` : | a XfcePanelPlugin
`widget` : | widget to focus

### xfce_panel_plugin_set_panel_hidden ()

    void                xfce_panel_plugin_set_panel_hidden  (XfcePanelPlugin *plugin,
                                                             gboolean hidden);

Ask the panel to hide or unhide. This only has effect when autohide is enabled.

`plugin` : | a XfcePanelPlugin
`hidden` : | `FALSE` to unhide, `TRUE` to hide the panel

## Property Details

### The `"display-name"` property

      "display-name"             gchar*                : Read

Translated plugin name. This is the name that can be presented to the user, e.g. in dialogs or menus.

Default value: NULL

### The `"expand"` property

      "expand"                   gboolean              : Read / Write

Whether to expand the plugin when the panel width increases.

Default value: FALSE

### The `"id"` property

      "id"                       gchar*                : Read

Unique identifier string created for every XfcePanelPlugin instance.

Default value: NULL

### The `"name"` property

      "name"                     gchar*                : Read

Untranslated plugin name. This identifies the plugin type and therefore has to be unique.

Default value: NULL

### The `"screen-position"` property

      "screen-position"          XfceScreenPosition    : Read

The current XfceScreenPosition of the panel.

Default value: XFCE_SCREEN_POSITION_S

### The `"size"` property

      "size"                     gint                  : Read

The current panel size.

Allowed values: [10,128]

Default value: 32

## Signal Details

### The `"about"` signal

    void                user_function                      (XfcePanelPlugin *plugin,
                                                            gpointer         user_data)      : Run Last / No Recursion / No Hooks

Emitted when the 'About' menu item is clicked. Plugin writers should connect to this signal to show information about their plugin (and its authors).

See also: `xfce_panel_plugin_menu_show_about()`

`plugin` : | a XfcePanelPlugin widget
`user_data` : | user data set when the signal handler was connected.

### The `"configure-plugin"` signal

    void                user_function                      (XfcePanelPlugin *plugin,
                                                            gpointer         user_data)      : Run Last / No Recursion / No Hooks

Emitted when the 'Configure' menu item is clicked. Plugin writers should connect to this signal to show a settings dialog.

See also: `xfce_panel_plugin_menu_show_configure()`

`plugin` : | a XfcePanelPlugin widget
`user_data` : | user data set when the signal handler was connected.

### The `"free-data"` signal

    void                user_function                      (XfcePanelPlugin *plugin,
                                                            gpointer         user_data)      : Run Last / No Recursion / No Hooks

Emitted when the panel is closing. Plugin writers should connect to this signal to free any allocated resources.

See also: "save"

`plugin` : | a XfcePanelPlugin widget
`user_data` : | user data set when the signal handler was connected.

### The `"orientation-changed"` signal

    void                user_function                      (XfcePanelPlugin *plugin,
                                                            GtkOrientation   orientation,
                                                            gpointer         user_data)        : Run Last / No Recursion / No Hooks

Emitted when the panel orientation changes.

`plugin` : | a XfcePanelPlugin widget
`orientation` : | new GtkOrientation of the panel
`user_data` : | user data set when the signal handler was connected.

### The `"save"` signal

    void                user_function                      (XfcePanelPlugin *plugin,
                                                            gpointer         user_data)      : Run Last / No Recursion / No Hooks

Emitted before the panel is closing. May be called more than once while the panel is running. Plugin writers should connect to this signal to save the plugins configuration.

See also: `xfce_panel_plugin_get_rc_file()`

`plugin` : | a XfcePanelPlugin widget
`user_data` : | user data set when the signal handler was connected.

### The `"screen-position-changed"` signal

    void                user_function                      (XfcePanelPlugin   *plugin,
                                                            XfceScreenPosition position,
                                                            gpointer           user_data)      : Run Last / No Recursion / No Hooks

Emitted when the screen position changes. Most plugins will be more interested in the "orientation-changed" signal.

`plugin` : | a XfcePanelPlugin widget
`position` : | new XfceScreenPosition of the panel
`user_data` : | user data set when the signal handler was connected.

### The `"size-changed"` signal

    gboolean            user_function                      (XfcePanelPlugin *plugin,
                                                            gint             size,
                                                            gpointer         user_data)      : Run Last / No Recursion / No Hooks

Emitted when the panel size changes.

`plugin` : | a XfcePanelPlugin widget
`size` : | new panel size
`user_data` : | user data set when the signal handler was connected.
Returns : | `TRUE` when handled, `FALSE` otherwise.

## See Also

Register Plugins