asp.net mvc qr code generator CONTAINER WIDGETS in Font

Create ECC200 in Font CONTAINER WIDGETS

There are three methods provided for changing the current page. If you know the specific index of the page you want to view, you can use gtk_notebook_set_current_page() to move to that page. void gtk_notebook_set_current_page (GtkNotebook *notebook, gint page_number); At times, you may also want switch to the next or previous tab, which can be done with call gtk_notebook_next_page() or gtk_notebook_prev_page(). If a call to either of these functions would cause the current tab to drop below zero or go above the current number of tabs, nothing will occur; the call will be ignored. When deciding what page to move to, it is often useful to know the current page and the total number of tabs. These values can be obtained with gtk_notebook_get_current_page() and gtk_notebook_get_n_pages() respectively.

Various widgets including GtkLabel do not respond to GDK events, because they do not have an associated GDK window. To fix this, GTK+ provides a container widget called GtkEventBox. Event boxes catch events for the child widget by providing a GDK window for the object. Listing 3-9 connects the button-press-event signal to a GtkLabel by using an event box. The text in the label is changed based on its current state when the label is double-clicked. Nothing visible happens when a single click occurs, although the signal is still emitted in that case. Listing 3-9. Adding Events to a GtkLabel (eventboxes.c) #include <gtk/gtk.h> static gboolean button_pressed (GtkWidget*, GdkEventButton*, GtkLabel*); int main (int argc, char *argv[]) { GtkWidget *window, *eventbox, *label; gtk_init (&argc, &argv); window = gtk_window_new (GTK_WINDOW_TOPLEVEL); gtk_window_set_title (GTK_WINDOW (window), "Event Box"); gtk_container_set_border_width (GTK_CONTAINER (window), 10); gtk_widget_set_size_request (window, 200, 50);

eventbox = gtk_event_box_new (); label = gtk_label_new ("Double-Click Me!"); /* Set the order in which widgets will receive notification of events. */ gtk_event_box_set_above_child (GTK_EVENT_BOX (eventbox), FALSE); g_signal_connect (G_OBJECT (eventbox), "button_press_event", G_CALLBACK (button_pressed), (gpointer) label); gtk_container_add (GTK_CONTAINER (eventbox), label); gtk_container_add (GTK_CONTAINER (window), eventbox); /* Allow the event box to catch button presses, realize the widget, and set the * cursor that will be displayed when the mouse is over the event box. */ gtk_widget_set_events (eventbox, GDK_BUTTON_PRESS_MASK); gtk_widget_realize (eventbox); gdk_window_set_cursor (eventbox->window, gdk_cursor_new (GDK_HAND1)); gtk_widget_show_all (window); gtk_main (); return 0; } /* This is called every time a button-press event occurs on the GtkEventBox. */ static gboolean button_pressed (GtkWidget *eventbox, GdkEventButton *event, GtkLabel *label) { if (event->type == GDK_2BUTTON_PRESS) { const gchar *text = gtk_label_get_text (label); if (text[0] == 'D') gtk_label_set_text (label, "I Was Double-Clicked!"); else gtk_label_set_text (label, "Double-Click Me Again!"); } return FALSE; }

When using an event box, you need to decide whether the event box s GdkWindow should be positioned above the windows of its child or below them. If the event box window is above, all events inside the event box will go to the event box. If the window is below, events in windows of child widgets will first go to that widget and then to its parents.

Note If you set the window s position as below, events do go to child widgets first. However, this is only the case for widgets that have associated GDK windows. If the child is a GtkLabel widget, it does not have the ability to detect events on its own. Therefore, it does not matter whether you set the window s position as above or below in Listing 3-9.

The location of the event box window can be moved above or below its children with gtk_event_box_set_above_child(). By default, this property is set to FALSE for all event boxes. This means that all events will be handled by the widget for which the signal was first emitted. The event will then be passed to its parent after the widget is finished. void gtk_event_box_set_above_child (GtkEventBox *event_box, gboolean above_child); Next, you need to add an event mask to the event box so that it knows what type of events the widget will receive. Values for the GdkEventMask enumeration that specify event masks are shown in Table 3-3. A bitwise list of GdkEventMask values can be passed to gtk_widget_set_events() if you need to set more than one. Table 3-3. GdkEventMask Values