GUI development

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Almost everything in NavIt works as a plugin, and so do the guis.

Initializing your gui[edit]

You have to provide a function plugin_init in your plugin.

This function should call

plugin_register_gui_type("gui-name", function);

The function has the following parameters: struct gui_methods *meth, int w, int h

  • meth is a structure with gui-functions you have to fill
  • w is the expected width
  • h is the expected height of the gui.

But you might ignore w and h, they are only recommendations.

meth should be filled with the following data:

  • menubar_new
  • toolbar_new
  • statusbar_new
  • popup_new
  • set_graphics

You can probably implement menubar_new, toolbar_new, statusbar_new and popup_new as a dummy, since it is rather GTK-specific, but set_graphics is required. It connects the graphics to the gui.

 struct gui_methods gui_<plugin>_methods = {

Here is a code sample :

 	dbg(1,"registering <your plugin>\n");
 	plugin_register_gui_type("<your plugin>", <your init function>);

Now, here is a sample of the init function :

 static struct gui_priv *
 gui_<plugin>_new(struct navit *nav, struct gui_methods *meth, struct attr **attrs) 
 	dbg(1,"Begin initialization of <your plugin>\n");
 	struct gui_priv *this_;
 	this_=g_new0(struct gui_priv, 1);
 	// Perform initializations specific to your gui
 	// ...
 	// If you want to register a callback function for the vehicle, you can do it so:
 	struct callback *cb=callback_new_0(callback_cast(vehicle_callback_handler));
 	return this_;

And you plugin (gui) should initialize. Now, you need somme dummy functions (for now). Thoses are requested for GTK.

 static struct menu_priv *
 gui_<plugin>_toolbar_new(struct gui_priv *this_, struct menu_methods *meth)
 	return NULL;
 static struct statusbar_priv *
 gui_<plugin>_statusbar_new(struct gui_priv *gui, struct statusbar_methods *meth)
 	return NULL;
 static struct menu_priv *
 gui_<plugin>_popup_new(struct gui_priv *this_, struct menu_methods *meth)
 	return NULL;

The following function allows to get menu entries for bookmarks

 static struct menu_priv *
 gui_<plugin>_menubar_new(struct gui_priv *this_, struct menu_methods *meth)
 	return (struct menu_priv *) 1;

The plugin main()[edit]

And, last but not least :

 static int gui_run_main_loop(struct gui_priv *this_)
        // Whatever needs to be done right before beginning the navigation
        // Define your viewport
 	struct map_selection sel;
 	memset(&sel, 0, sizeof(sel));
 	transform_set_screen_selection(navit_get_trans(this_->nav), &sel);
        // Register the callback to handle navigation instructions updates
 	struct navigation *navig;
 		callback_new_0((void (*)())update_roadbook)
 	timeout = g_timeout_source_new(100);
 	g_source_set_callback(timeout, gui_timeout_cb, NULL, NULL);
 	g_source_attach(timeout, NULL);
 	while (!must_quit)
        //Poll event, process them
        // Call update of gps
        g_main_context_iteration (NULL, TRUE);
        // Any other task you may need