Difference between revisions of "GUI development"

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Revision as of 20:55, 3 December 2012


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

Initializing your gui

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()

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