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GTK+ Reference Manual | ![]() |
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Prior to GTK+ 2.4, some applications used the GnomeUIInfo
mechanism from
<libgnomeui/gnome-app-helper.h>
to
define their menus and toolbars. With it, a program decleres an
array of GnomeUIInfo structures, which
contain information for menu or toolbar items such as their
label, icon, and accelerator key. Then, one calls
gnome_app_fill_menu()
or gnome_app_fill_toolbar()
, or one of the
related functions, to create the appropriate widgets based on
these structures.
A downside of this API is that the same structures are used to
pass back pointers to the widgets that got created. This means
that the structures cannot simply be kept around if the program
requires multiple instances of the user interface (e.g. several
windows); each new invocation of gnome_app_fill_menu()
would
overwrite the widget fields of the structures.
Another disadvantage is that there is no automatic way to synchronize the state of related controls. If there are toolbar toogle buttons for "Bold", "Italic", "Underline", and also corresponding menu items under "Format/Bold", etc., one has to synchronize their toggled states by hand whenever the user selects any one of them.
Finally, there is no way to do menu and toolbar merging for applications that require embedded components.
To convert an application that uses GnomeUIInfo into the new GtkAction mechanism, you need to do several things:
Separate your existing GnomeUIInfo entries into normal actions, toggle actions, and radio actions, and then create a separate array of GtkActionEntry structures for each group. This will allow you to create the necessary GtkActionGroup objects. Note that this does not describe the actual "shape" that your menus and toolbars will have; it simply defines the set of commands that will appear in them.
Create an XML description of your menus and toolbars for use with GtkUIManager. This defines the actual shape of the menus and toolbars.
Port the code that uses gnome-app and gnome-app-helper to GtkAction and GtkUIManager.
If your GnomeUIInfo entries use GNOME_APP_PIXMAP_DATA or GNOME_APP_PIXMAP_FILENAME for pixmaps, you have to create a GtkIconFactory, add it to the list of default factories, then create a GtkIconSet for each of your own icons. Add the sets to the factory, and use the id in the GtkActionEntry like a regular GTK+ stock id.
Example 58. GnomeUIInfo Example
The following code shows a declaration of a simple menu bar to
be used with gnome_app_fill_menu()
or similar. The menu hierarchy i
looks like this:
static GnomeUIInfo file_menu_items[] = { { GNOME_APP_UI_ITEM, "_Open", "Open a file", open_callback, NULL, NULL, GNOME_APP_PIXMAP_STOCK, GTK_STOCK_OPEN, 'o', GDK_CONTROL_MASK, NULL }, { GNOME_APP_UI_SEPARATOR }, { GNOME_APP_UI_ITEM, "E_xit", "Exit the program", exit_callback, NULL, NULL, GNOME_APP_PIXMAP_STOCK, GTK_STOCK_QUIT, 'q', GDK_CONTROL_MASK, NULL}, { GNOME_APP_UI_ENDOFINFO } }; static GnomeUIInfo view_radio_items[] = { { GNOME_APP_UI_ITEM, "_High Quality", "Display images in high quality, slow mode", high_quality_callback, NULL, NULL, GNOME_APP_PIXMAP_FILENAME, "high-quality.png", 0, 0, NULL }, { GNOME_APP_UI_ITEM, "_Normal Quality", "Display images in normal quality", normal_quality_callback, NULL, NULL, GNOME_APP_PIXMAP_FILENAME, "normal-quality.png", 0, 0, NULL }, { GNOME_APP_UI_ITEM, "_Low Quality", "Display images in low quality, fast mode", low_quality_callback, NULL, NULL, GNOME_APP_PIXMAP_FILENAME, "low-quality.png", 0, 0, NULL }, { GNOME_APP_UI_ENDOFINFO } }; static GnomeUIInfo view_menu_items[] = { { GNOME_APP_UI_ITEM, "Zoom _In", "Zoom into the image", zoom_in_callback, NULL, NULL, GNOME_APP_PIXMAP_STOCK, GTK_STOCK_ZOOM_IN, GDK_PLUS, 0, NULL }, { GNOME_APP_UI_ITEM, "Zoom _Out", "Zoom away from the image", zoom_out_callback, NULL, NULL, GNOME_APP_PIXMAP_STOCK, GTK_STOCK_ZOOM_OUT, GDK_MINUS, 0, NULL }, { GNOME_APP_UI_SEPARATOR }, { GNOME_APP_UI_TOGGLEITEM, "_Full Screen", "Switch between full screen and windowed mode", full_screen_callback, NULL, NULL, GNOME_APP_PIXMAP_NONE, NULL, GDK_F11, 0, NULL }, { GNOME_APP_UI_SEPARATOR }, { GNOME_APP_UI_RADIOITEMS, NULL, NULL, view_radio_items }, { GNOME_APP_UI_ENDOFINFO } }; static GnomeUIInfo menubar[] = { { GNOME_APP_UI_SUBTREE, "_File", NULL, file_menu_items }, { GNOME_APP_UI_SUBTREE, "_View", NULL, view_menu_items }, { GNOME_APP_UI_ENDOFINFO } }
Example 59. GtkActionEntry Structures
The following code is the set of actions that are present in
the previous
example. Note that the toggle and radio entries are
separate from normal actions. Also, note that GtkActionEntry
structures take key names in the format of gtk_accelerator_parse()
rather than key values plus modifiers; you will have to convert these
values by hand. For example, GDK_F11
with no modifiers is equivalent
to a key name of "F11"
. Likewise, "o"
with GDK_CONTROL_MASK
is equivalent to "<ontrol>O"
.
/* Normal items */ static const GtkActionEntry entries[] = { { "FileMenu", NULL, "_File" }, { "ViewMenu", NULL, "_View" }, { "Open", GTK_STOCK_OPEN, "_Open", "<control>O", "Open a file", open_action_callback }, { "Exit", GTK_STOCK_QUIT, "E_xit", "<control>Q", "Exit the program", exit_action_callback }, { "ZoomIn", GTK_STOCK_ZOOM_IN, "Zoom _In", "plus", "Zoom into the image", zoom_in_action_callback }, { "ZoomOut", GTK_STOCK_ZOOM_OUT, "Zoom _Out", "minus", "Zoom away from the image", zoom_out_action_callback }, }; /* Toggle items */ static const GtkToggleActionEntry toggle_entries[] = { { "FullScreen", NULL, "_Full Screen", "F11", "Switch between full screen and windowed mode", full_screen_action_callback, FALSE } }; /* Radio items */ static const GtkRadioActionEntry radio_entries[] = { { "HighQuality", "my-stock-high-quality", "_High Quality", NULL, "Display images in high quality, slow mode", 0 }, { "NormalQuality", "my-stock-normal-quality", "_Normal Quality", NULL, "Display images in normal quality", 1 }, { "LowQuality", "my-stock-low-quality", "_Low Quality", NULL, "Display images in low quality, fast mode", 2 } };
Example 60. XML Description
After extracting the actions, you will need to create an XML description of the actual layout of your menus and toolbars for use with GtkUIManager. The following code shows a simple menu bar that corresponds to the previous example. Note that the and menus have their names specified in the action entries, not in the XML itself. This is because the XML description only contains identifiers for the items in the GUI, rather than human-readable names.
static const char *ui_description = "<ui>" " <menubar name='MainMenu'>" " <menu action='FileMenu'>" " <menuitem action='Open'/>" " <menuitem action='Exit'/>" " </menu>" " <menu action='ViewMenu'>" " <menuitem action='ZoomIn'/>" " <menuitem action='ZoomOut'/>" " <separator/>" " <menuitem action='FullScreen'/>" " <separator/>" " <menuitem action='HighQuality'/>" " <menuitem action='NormalQuality'/>" " <menuitem action='LowQuality'/>" " </menu>" " </menubar>" "</ui>";
Example 61. Creating the Menu Bar
In this last example, we will create a GtkActionGroup based on the action entries we created above. We will then create a GtkUIManager with the XML description of the menu layout. We will also extract the accelerator group and the widgets from the GtkUIManager put them into a window.
GtkWidget *window; GtkWidget *vbox; GtkWidget *menubar; GtkActionGroup *action_group; GtkUIManager *ui_manager; GtkAccelGroup *accel_group; GError *error; register_my_stock_icons (); window = gtk_window_new (GTK_WINDOW_TOPLEVEL); vbox = gtk_vbox_new (FALSE, 0); gtk_container_add (GTK_CONTAINER (window), vbox); action_group = gtk_action_group_new ("MenuActions"); gtk_action_group_add_actions (action_group, entries, G_N_ELEMENTS (entries), window); gtk_action_group_add_toggle_actions (action_group, toggle_entries, G_N_ELEMENTS (toggle_entries), window); gtk_action_group_add_radio_actions (action_group, radio_entries, G_N_ELEMENTS (radio_entries), 0, radio_action_callback, window); ui_manager = gtk_ui_manager_new (); gtk_ui_manager_insert_action_group (ui_manager, action_group, 0); accel_group = gtk_ui_manager_get_accel_group (ui_manager); gtk_window_add_accel_group (GTK_WINDOW (window), accel_group); error = NULL; if (!gtk_ui_manager_add_ui_from_string (ui_manager, ui_description, -1, &error)) { g_message ("building menus failed: %s", error->message); g_error_free (error); exit (EXIT_FAILURE); } menubar = gtk_ui_manager_get_widget (ui_manager, "/MainMenu"); gtk_box_pack_start (GTK_BOX (vbox), menubar, FALSE, FALSE, 0); gtk_widget_show_all (window);
Example 62. Registering the icons
Here we show how the register_my_stock_icons()
function
used in the previous example could look like.
static struct { gchar *filename; gchar *stock_id; } stock_icons[] = { { "high-quality.png", "my-stock-high-quality" }, { "normal-quality.png", "my-stock-normal-quality" }, { "low-quality.png", "my-stock-low-quality" }, }; static gint n_stock_icons = G_N_ELEMENTS (stock_icons); static void register_my_stock_icons (void) { GtkIconFactory *icon_factory; GtkIconSet *icon_set; GtkIconSource *icon_source; gint i; icon_factory = gtk_icon_factory_new (); for (i = 0; i < n_stock_icons; i++) { icon_set = gtk_icon_set_new (); icon_source = gtk_icon_source_new (); gtk_icon_source_set_filename (icon_source, stock_icons[i].filename); gtk_icon_set_add_source (icon_set, icon_source); gtk_icon_source_free (icon_source); gtk_icon_factory_add (icon_factory, stock_icons[i].stock_id, icon_set); gtk_icon_set_unref (icon_set); } gtk_icon_factory_add_default (icon_factory); g_object_unref (icon_factory); }