We've almost seen all there is to see of the button widget. It's pretty simple. There are however two ways to create a button. You can use the gtk_button_new_with_label() to create a button with a label, or use gtk_button_new() to create a blank button. It's then up to you to pack a label or pixmap into this new button. To do this, create a new box, and then pack your objects into this box using the usual gtk_box_pack_start, and then use gtk_container_add to pack the box into the button.
Here's an example of using gtk_button_new to create a button with a picture and a label in it. I've broken up the code to create a box from the rest so you can use it in your programs. There are further examples of using pixmaps later in the tutorial.
/* example-start buttons buttons.c */ #include <gtk/gtk.h> /* Create a new hbox with an image and a label packed into it * and return the box. */ GtkWidget *xpm_label_box( GtkWidget *parent, gchar *xpm_filename, gchar *label_text ) { GtkWidget *box1; GtkWidget *label; GtkWidget *pixmapwid; GdkPixmap *pixmap; GdkBitmap *mask; GtkStyle *style; /* Create box for xpm and label */ box1 = gtk_hbox_new (FALSE, 0); gtk_container_set_border_width (GTK_CONTAINER (box1), 2); /* Get the style of the button to get the * background color. */ style = gtk_widget_get_style(parent); /* Now on to the xpm stuff */ pixmap = gdk_pixmap_create_from_xpm (parent->window, &mask, &style->bg[GTK_STATE_NORMAL], xpm_filename); pixmapwid = gtk_pixmap_new (pixmap, mask); /* Create a label for the button */ label = gtk_label_new (label_text); /* Pack the pixmap and label into the box */ gtk_box_pack_start (GTK_BOX (box1), pixmapwid, FALSE, FALSE, 3); gtk_box_pack_start (GTK_BOX (box1), label, FALSE, FALSE, 3); gtk_widget_show(pixmapwid); gtk_widget_show(label); return(box1); } /* Our usual callback function */ void callback( GtkWidget *widget, gpointer data ) { g_print ("Hello again - %s was pressed\n", (char *) data); } int main( int argc, char *argv[] ) { /* GtkWidget is the storage type for widgets */ GtkWidget *window; GtkWidget *button; GtkWidget *box1; gtk_init (&argc, &argv); /* Create a new window */ window = gtk_window_new (GTK_WINDOW_TOPLEVEL); gtk_window_set_title (GTK_WINDOW (window), "Pixmap'd Buttons!"); /* It's a good idea to do this for all windows. */ gtk_signal_connect (GTK_OBJECT (window), "destroy", GTK_SIGNAL_FUNC (gtk_exit), NULL); gtk_signal_connect (GTK_OBJECT (window), "delete_event", GTK_SIGNAL_FUNC (gtk_exit), NULL); /* Sets the border width of the window. */ gtk_container_set_border_width (GTK_CONTAINER (window), 10); gtk_widget_realize(window); /* Create a new button */ button = gtk_button_new (); /* Connect the "clicked" signal of the button to our callback */ gtk_signal_connect (GTK_OBJECT (button), "clicked", GTK_SIGNAL_FUNC (callback), (gpointer) "cool button"); /* This calls our box creating function */ box1 = xpm_label_box(window, "info.xpm", "cool button"); /* Pack and show all our widgets */ gtk_widget_show(box1); gtk_container_add (GTK_CONTAINER (button), box1); gtk_widget_show(button); gtk_container_add (GTK_CONTAINER (window), button); gtk_widget_show (window); /* Rest in gtk_main and wait for the fun to begin! */ gtk_main (); return(0); } /* example-end */ |
The xpm_label_box function could be used to pack xpm's and labels into any widget that can be a container.
Notice in xpm_label_box how there is a call to gtk_widget_get_style. Every widget has a "style", consisting of foreground and background colors for a variety of situations, font selection, and other graphics data relevant to a widget. These style values are defaulted in each widget, and are required by many GDK function calls, such as gdk_pixmap_create_from_xpm, which here is given the "normal" background color. The style data of widgets may be customized, using GTK's rc files.
Also notice the call to gtk_widget_realize after setting the window's border width. This function uses GDK to create the X windows related to the widget. The function is automatically called when you invoke gtk_widget_show for a widget, and so has not been shown in earlier examples. But the call to gdk_pixmap_create_from_xpm requires that its window argument refer to a real X window, so it is necessary to realize the widget before this GDK call.
The Button widget has the following signals:
pressed - emitted when pointer button is pressed within Button widget
released - emitted when pointer button is released within Button widget
clicked - emitted when pointer button is pressed and then released within Button widget
enter - emitted when pointer enters Button widget
leave - emitted when pointer leaves Button widget