widget-factory: add an about dialog

This is a first step towards making widget-factory an installed
demo.

tests/widget-factory.c

@@ -22,6 +22,7 @@
  *
  */
 
+#include "config.h"
 #include <gtk/gtk.h>
 
 static void
@@ -35,6 +36,30 @@ dark_toggled (GtkCheckMenuItem *item, gpointer data)
                 NULL);
 }
 
+static void
+show_about (GtkMenuItem *item, GtkWidget *window)
+{
+  const gchar *authors[] = {
+    "Andrea Cimitan",
+    "Cosimo Cecchi"
+  };
+
+  gtk_show_about_dialog (GTK_WINDOW (window),
+                         "program-name", "GTK+ Widget Factory",
+                         "version", g_strdup_printf ("%s,\nRunning against GTK+ %d.%d.%d",
+                                                     PACKAGE_VERSION,
+                                                     gtk_get_major_version (),
+                                                     gtk_get_minor_version (),
+                                                     gtk_get_micro_version ()),
+                         "copyright", "(C) 1997-2009 The GTK+ Team",
+                         "license-type", GTK_LICENSE_LGPL_2_1,
+                         "website", "http://www.gtk.org",
+                         "comments", "Program to demonstrate GTK+ themes and widgets",
+                         "authors", authors,
+                         "title", "About GTK+ Widget Factory",
+                         NULL);
+}
+
 int
 main (int argc, char *argv[])
 {
@@ -58,6 +83,9 @@ main (int argc, char *argv[])
   g_signal_connect (widget, "toggled", G_CALLBACK (dark_toggled), NULL);
   gtk_check_menu_item_set_active (GTK_CHECK_MENU_ITEM (widget), dark);
 
+  widget = (GtkWidget*) gtk_builder_get_object (builder, "aboutmenuitem");
+  g_signal_connect (widget, "activate", G_CALLBACK (show_about), window);
+
   g_object_unref (G_OBJECT (builder));
 
   gtk_widget_show (window);

tests/widget-factory.ui

@@ -54,6 +54,7 @@ Suspendisse feugiat quam quis dolor accumsan cursus. </property>
   <object class="GtkAccelGroup" id="accelgroup1"/>
   <object class="GtkWindow" id="window">
     <property name="can_focus">False</property>
+    <property name="title">GTK+ Widget Factory</property>
     <signal name="destroy" handler="gtk_main_quit" swapped="no"/>
     <signal name="delete-event" handler="gtk_false" swapped="no"/>
     <child>
@@ -390,7 +391,7 @@ Suspendisse feugiat quam quis dolor accumsan cursus. </property>
                     <property name="visible">True</property>
                     <property name="can_focus">False</property>
                     <child>
-                      <object class="GtkImageMenuItem" id="imagemenuitem10">
+                      <object class="GtkImageMenuItem" id="aboutmenuitem">
                         <property name="label">gtk-about</property>
                         <property name="visible">True</property>
                         <property name="can_focus">False</property>