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