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Chapter 7. The Button Widget

7.1. Normal Buttons

We've almost seen all there is to see of the button widget. It's pretty simple. There is however more than one way to create a button. You can use the gtk_button_new_with_label() or gtk_button_new_with_mnemonic() to create a button with a label, use gtk_button_new_from_stock() to create a button containing the image and text from a stock item 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 image 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 images later in the tutorial.


#include <stdlib.h>
#include <gtk/gtk.h>

/* Create a new hbox with an image and a label packed into it
 * and return the box. */

static GtkWidget *xpm_label_box( gchar     *xpm_filename,
                                 gchar     *label_text )
{
    GtkWidget *box;
    GtkWidget *label;
    GtkWidget *image;

    /* Create box for image and label */
    box = gtk_hbox_new (FALSE, 0);
    gtk_container_set_border_width (GTK_CONTAINER (box), 2);

    /* Now on to the image stuff */
    image = gtk_image_new_from_file (xpm_filename);

    /* Create a label for the button */
    label = gtk_label_new (label_text);

    /* Pack the image and label into the box */
    gtk_box_pack_start (GTK_BOX (box), image, FALSE, FALSE, 3);
    gtk_box_pack_start (GTK_BOX (box), label, FALSE, FALSE, 3);

    gtk_widget_show (image);
    gtk_widget_show (label);

    return box;
}

/* Our usual callback function */
static 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 *box;

    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. */
    g_signal_connect (G_OBJECT (window), "destroy",
	              G_CALLBACK (gtk_main_quit), NULL);

    g_signal_connect (G_OBJECT (window), "delete_event",
	 	      G_CALLBACK (gtk_main_quit), NULL);

    /* Sets the border width of the window. */
    gtk_container_set_border_width (GTK_CONTAINER (window), 10);

    /* Create a new button */
    button = gtk_button_new ();

    /* Connect the "clicked" signal of the button to our callback */
    g_signal_connect (G_OBJECT (button), "clicked",
		      G_CALLBACK (callback), (gpointer) "cool button");

    /* This calls our box creating function */
    box = xpm_label_box ("info.xpm", "cool button");

    /* Pack and show all our widgets */
    gtk_widget_show (box);

    gtk_container_add (GTK_CONTAINER (button), box);

    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;
}

The xpm_label_box() function could be used to pack images and labels into any widget that can be a container.

The Button widget has the following signals: