added an event watcher for enter/leave based on signal emission hooks.

Mon Nov 30 06:20:36 1998  Tim Janik  <timj@gtk.org>

        * gtk/testgtk.c: added an event watcher for enter/leave based on
        signal emission hooks.

        * gtk/gtkobject.c (gtk_object_class_init): made GtkObject::destroy a
        GTK_RUN_NO_HOOKS signal.

        * gtk/gtksignal.h:
        * gtk/gtksignal.c: implemented emission hooks, new hooks can be added
        to a signal with gtk_signal_add_emission_hook or
        gtk_signal_add_emission_hook_full, and can be removed again with
        gtk_signal_remove_emission_hook.

        * gtk/gtkenums.h: remove GTK_RUN_MASK, since it doesn't represent
        an appropriate mask for signal runtypes for a long time now.
        added GTK_RUN_NO_HOOKS value, which is used to flag signals
        that do not allow the running of signal hooks.

13 files changed, 459 insertions, 20 deletions

diff --git a/ChangeLog b/ChangeLog
index ed39fe00e..05e15c24d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,22 @@
+Mon Nov 30 06:20:36 1998  Tim Janik  <timj@gtk.org>
+
+	* gtk/testgtk.c: added an event watcher for enter/leave based on
+	signal emission hooks.
+
+	* gtk/gtkobject.c (gtk_object_class_init): made GtkObject::destroy a
+	GTK_RUN_NO_HOOKS signal.
+
+	* gtk/gtksignal.h: 
+	* gtk/gtksignal.c: implemented emission hooks, new hooks can be added
+	to a signal with gtk_signal_add_emission_hook or
+	gtk_signal_add_emission_hook_full, and can be removed again with
+	gtk_signal_remove_emission_hook.
+
+	* gtk/gtkenums.h: remove GTK_RUN_MASK, since it doesn't represent
+	an appropriate mask for signal runtypes for a long time now.
+	added GTK_RUN_NO_HOOKS value, which is used to flag signals
+	that do not allow the running of signal hooks.
+
 1998-11-26  Michael Krause  <m.krause@tu-harburg.de>
 
         * gtk/gtknotebook.c (gtk_notebook_switch_page): made 'page_num'
diff --git a/ChangeLog.pre-2-0 b/ChangeLog.pre-2-0
index ed39fe00e..05e15c24d 100644
--- a/ChangeLog.pre-2-0
+++ b/ChangeLog.pre-2-0
@@ -1,3 +1,22 @@
+Mon Nov 30 06:20:36 1998  Tim Janik  <timj@gtk.org>
+
+	* gtk/testgtk.c: added an event watcher for enter/leave based on
+	signal emission hooks.
+
+	* gtk/gtkobject.c (gtk_object_class_init): made GtkObject::destroy a
+	GTK_RUN_NO_HOOKS signal.
+
+	* gtk/gtksignal.h: 
+	* gtk/gtksignal.c: implemented emission hooks, new hooks can be added
+	to a signal with gtk_signal_add_emission_hook or
+	gtk_signal_add_emission_hook_full, and can be removed again with
+	gtk_signal_remove_emission_hook.
+
+	* gtk/gtkenums.h: remove GTK_RUN_MASK, since it doesn't represent
+	an appropriate mask for signal runtypes for a long time now.
+	added GTK_RUN_NO_HOOKS value, which is used to flag signals
+	that do not allow the running of signal hooks.
+
 1998-11-26  Michael Krause  <m.krause@tu-harburg.de>
 
         * gtk/gtknotebook.c (gtk_notebook_switch_page): made 'page_num'
diff --git a/ChangeLog.pre-2-10 b/ChangeLog.pre-2-10
index ed39fe00e..05e15c24d 100644
--- a/ChangeLog.pre-2-10
+++ b/ChangeLog.pre-2-10
@@ -1,3 +1,22 @@
+Mon Nov 30 06:20:36 1998  Tim Janik  <timj@gtk.org>
+
+	* gtk/testgtk.c: added an event watcher for enter/leave based on
+	signal emission hooks.
+
+	* gtk/gtkobject.c (gtk_object_class_init): made GtkObject::destroy a
+	GTK_RUN_NO_HOOKS signal.
+
+	* gtk/gtksignal.h: 
+	* gtk/gtksignal.c: implemented emission hooks, new hooks can be added
+	to a signal with gtk_signal_add_emission_hook or
+	gtk_signal_add_emission_hook_full, and can be removed again with
+	gtk_signal_remove_emission_hook.
+
+	* gtk/gtkenums.h: remove GTK_RUN_MASK, since it doesn't represent
+	an appropriate mask for signal runtypes for a long time now.
+	added GTK_RUN_NO_HOOKS value, which is used to flag signals
+	that do not allow the running of signal hooks.
+
 1998-11-26  Michael Krause  <m.krause@tu-harburg.de>
 
         * gtk/gtknotebook.c (gtk_notebook_switch_page): made 'page_num'
diff --git a/ChangeLog.pre-2-2 b/ChangeLog.pre-2-2
index ed39fe00e..05e15c24d 100644
--- a/ChangeLog.pre-2-2
+++ b/ChangeLog.pre-2-2
@@ -1,3 +1,22 @@
+Mon Nov 30 06:20:36 1998  Tim Janik  <timj@gtk.org>
+
+	* gtk/testgtk.c: added an event watcher for enter/leave based on
+	signal emission hooks.
+
+	* gtk/gtkobject.c (gtk_object_class_init): made GtkObject::destroy a
+	GTK_RUN_NO_HOOKS signal.
+
+	* gtk/gtksignal.h: 
+	* gtk/gtksignal.c: implemented emission hooks, new hooks can be added
+	to a signal with gtk_signal_add_emission_hook or
+	gtk_signal_add_emission_hook_full, and can be removed again with
+	gtk_signal_remove_emission_hook.
+
+	* gtk/gtkenums.h: remove GTK_RUN_MASK, since it doesn't represent
+	an appropriate mask for signal runtypes for a long time now.
+	added GTK_RUN_NO_HOOKS value, which is used to flag signals
+	that do not allow the running of signal hooks.
+
 1998-11-26  Michael Krause  <m.krause@tu-harburg.de>
 
         * gtk/gtknotebook.c (gtk_notebook_switch_page): made 'page_num'
diff --git a/ChangeLog.pre-2-4 b/ChangeLog.pre-2-4
index ed39fe00e..05e15c24d 100644
--- a/ChangeLog.pre-2-4
+++ b/ChangeLog.pre-2-4
@@ -1,3 +1,22 @@
+Mon Nov 30 06:20:36 1998  Tim Janik  <timj@gtk.org>
+
+	* gtk/testgtk.c: added an event watcher for enter/leave based on
+	signal emission hooks.
+
+	* gtk/gtkobject.c (gtk_object_class_init): made GtkObject::destroy a
+	GTK_RUN_NO_HOOKS signal.
+
+	* gtk/gtksignal.h: 
+	* gtk/gtksignal.c: implemented emission hooks, new hooks can be added
+	to a signal with gtk_signal_add_emission_hook or
+	gtk_signal_add_emission_hook_full, and can be removed again with
+	gtk_signal_remove_emission_hook.
+
+	* gtk/gtkenums.h: remove GTK_RUN_MASK, since it doesn't represent
+	an appropriate mask for signal runtypes for a long time now.
+	added GTK_RUN_NO_HOOKS value, which is used to flag signals
+	that do not allow the running of signal hooks.
+
 1998-11-26  Michael Krause  <m.krause@tu-harburg.de>
 
         * gtk/gtknotebook.c (gtk_notebook_switch_page): made 'page_num'
diff --git a/ChangeLog.pre-2-6 b/ChangeLog.pre-2-6
index ed39fe00e..05e15c24d 100644
--- a/ChangeLog.pre-2-6
+++ b/ChangeLog.pre-2-6
@@ -1,3 +1,22 @@
+Mon Nov 30 06:20:36 1998  Tim Janik  <timj@gtk.org>
+
+	* gtk/testgtk.c: added an event watcher for enter/leave based on
+	signal emission hooks.
+
+	* gtk/gtkobject.c (gtk_object_class_init): made GtkObject::destroy a
+	GTK_RUN_NO_HOOKS signal.
+
+	* gtk/gtksignal.h: 
+	* gtk/gtksignal.c: implemented emission hooks, new hooks can be added
+	to a signal with gtk_signal_add_emission_hook or
+	gtk_signal_add_emission_hook_full, and can be removed again with
+	gtk_signal_remove_emission_hook.
+
+	* gtk/gtkenums.h: remove GTK_RUN_MASK, since it doesn't represent
+	an appropriate mask for signal runtypes for a long time now.
+	added GTK_RUN_NO_HOOKS value, which is used to flag signals
+	that do not allow the running of signal hooks.
+
 1998-11-26  Michael Krause  <m.krause@tu-harburg.de>
 
         * gtk/gtknotebook.c (gtk_notebook_switch_page): made 'page_num'
diff --git a/ChangeLog.pre-2-8 b/ChangeLog.pre-2-8
index ed39fe00e..05e15c24d 100644
--- a/ChangeLog.pre-2-8
+++ b/ChangeLog.pre-2-8
@@ -1,3 +1,22 @@
+Mon Nov 30 06:20:36 1998  Tim Janik  <timj@gtk.org>
+
+	* gtk/testgtk.c: added an event watcher for enter/leave based on
+	signal emission hooks.
+
+	* gtk/gtkobject.c (gtk_object_class_init): made GtkObject::destroy a
+	GTK_RUN_NO_HOOKS signal.
+
+	* gtk/gtksignal.h: 
+	* gtk/gtksignal.c: implemented emission hooks, new hooks can be added
+	to a signal with gtk_signal_add_emission_hook or
+	gtk_signal_add_emission_hook_full, and can be removed again with
+	gtk_signal_remove_emission_hook.
+
+	* gtk/gtkenums.h: remove GTK_RUN_MASK, since it doesn't represent
+	an appropriate mask for signal runtypes for a long time now.
+	added GTK_RUN_NO_HOOKS value, which is used to flag signals
+	that do not allow the running of signal hooks.
+
 1998-11-26  Michael Krause  <m.krause@tu-harburg.de>
 
         * gtk/gtknotebook.c (gtk_notebook_switch_page): made 'page_num'
diff --git a/gtk/gtkenums.h b/gtk/gtkenums.h
index d03eddd12..3dd9a8aa7 100644
--- a/gtk/gtkenums.h
+++ b/gtk/gtkenums.h
@@ -194,12 +194,12 @@ typedef enum
 /* signal run types */
 typedef enum			/*< flags >*/
 {
-  GTK_RUN_FIRST      = 0x1,
-  GTK_RUN_LAST       = 0x2,
-  GTK_RUN_BOTH       = 0x3,
-  GTK_RUN_MASK       = 0xF,
+  GTK_RUN_FIRST      = 0x01,
+  GTK_RUN_LAST       = 0x02,
+  GTK_RUN_BOTH       = (GTK_RUN_FIRST | GTK_RUN_LAST),
   GTK_RUN_NO_RECURSE = 0x10,
-  GTK_RUN_ACTION  = 0x20
+  GTK_RUN_ACTION     = 0x20,
+  GTK_RUN_NO_HOOKS   = 0x30
 } GtkSignalRunType;
 
 /* scrolling types */
diff --git a/gtk/gtkobject.c b/gtk/gtkobject.c
index 15dd70608..c8b727428 100644
--- a/gtk/gtkobject.c
+++ b/gtk/gtkobject.c
@@ -166,7 +166,7 @@ gtk_object_class_init (GtkObjectClass *class)
 
   object_signals[DESTROY] =
     gtk_signal_new ("destroy",
-                    GTK_RUN_LAST,
+                    GTK_RUN_LAST | GTK_RUN_NO_HOOKS,
                     class->type,
                     GTK_SIGNAL_OFFSET (GtkObjectClass, destroy),
                     gtk_marshal_NONE__NONE,
diff --git a/gtk/gtksignal.c b/gtk/gtksignal.c
index f9b3bec44..7bfd9ee17 100644
--- a/gtk/gtksignal.c
+++ b/gtk/gtksignal.c
@@ -36,7 +36,7 @@ enum
   EMISSION_DONE
 };
 
-#define GTK_RUN_TYPE(x)	 ((x) & GTK_RUN_MASK)
+#define GTK_RUN_TYPE(x)	 ((x) & GTK_RUN_BOTH)
 
 
 typedef struct _GtkSignal		GtkSignal;
@@ -55,11 +55,12 @@ struct _GtkSignal
   GtkType	      object_type;
   gchar		     *name;
   guint		      function_offset;
-  GtkSignalRunType    signal_flags;
   GtkSignalMarshaller marshaller;
   GtkType	      return_val;
+  GtkSignalRunType    signal_flags : 16;
+  guint		      nparams : 16;
   GtkType	     *params;
-  guint		      nparams;
+  GHookList	     *hook_list;
 };
 
 struct _GtkSignalHash
@@ -145,7 +146,9 @@ static gint	    gtk_handlers_run	       (GtkHandler     *handlers,
 						GtkObject      *object,
 						GtkArg         *params,
 						gint		after);
-static gboolean	    gtk_signal_collect_params  (GtkArg	       *params,
+static gboolean gtk_emission_hook_marshaller   (GHook          *hook,
+						gpointer        data);
+static gboolean	gtk_signal_collect_params      (GtkArg	       *params,
 						guint		nparams,
 						GtkType	       *param_types,
 						GtkType		return_type,
@@ -303,10 +306,11 @@ gtk_signal_newv (const gchar	     *r_name,
   signal->object_type = object_type;
   signal->name = name;
   signal->function_offset = function_offset;
-  signal->signal_flags = signal_flags;
   signal->marshaller = marshaller;
   signal->return_val = return_val;
+  signal->signal_flags = signal_flags;
   signal->nparams = nparams;
+  signal->hook_list = NULL;
   
   if (nparams > 0)
     {
@@ -1419,7 +1423,17 @@ gtk_signal_real_emit (GtkObject *object,
 	    }
 	}
     }
-  
+
+  /* do *not* reorder this call! */
+  if (signal.hook_list)
+    {
+      gpointer data[2];
+
+      data[0] = &signal;
+      data[1] = object;
+      g_hook_list_marshal_check (signal.hook_list, TRUE, gtk_emission_hook_marshaller, &data);
+    }
+
  emission_done:
   
   gtk_emission_remove (&current_emissions, object, signal_id);
@@ -1517,6 +1531,90 @@ gtk_signal_handler_pending_by_func (GtkObject           *object,
   return handler_id;
 }
 
+guint
+gtk_signal_add_emission_hook (guint           signal_id,
+			      GtkEmissionHook hook_func,
+			      gpointer        data)
+{
+  return gtk_signal_add_emission_hook_full (signal_id, hook_func, data, NULL);
+}
+
+guint
+gtk_signal_add_emission_hook_full (guint           signal_id,
+				   GtkEmissionHook hook_func,
+				   gpointer        data,
+				   GDestroyNotify  destroy)
+{
+  static guint seq_hook_id = 1;
+  GtkSignal *signal;
+  GHook *hook;
+
+  g_return_val_if_fail (signal_id > 0, 0);
+  g_return_val_if_fail (hook_func != NULL, 0);
+  
+  signal = LOOKUP_SIGNAL_ID (signal_id);
+  g_return_val_if_fail (signal != NULL, 0);
+  if (signal->signal_flags & GTK_RUN_NO_HOOKS)
+    {
+      g_warning ("gtk_signal_add_emission_hook_full(): signal \"%s\" does not support emission hooks",
+		 signal->name);
+      return 0;
+    }
+
+  if (!signal->hook_list)
+    {
+      signal->hook_list = g_new (GHookList, 1);
+      g_hook_list_init (signal->hook_list, sizeof (GHook));
+    }
+
+  hook = g_hook_alloc (signal->hook_list);
+  hook->data = data;
+  hook->func = hook_func;
+  hook->destroy = destroy;
+
+  signal->hook_list->seq_id = seq_hook_id;
+  g_hook_prepend (signal->hook_list, hook);
+  seq_hook_id = signal->hook_list->seq_id;
+
+  return hook->hook_id;
+}
+
+void
+gtk_signal_remove_emission_hook (guint signal_id,
+				 guint hook_id)
+{
+  GtkSignal *signal;
+
+  g_return_if_fail (signal_id > 0);
+  g_return_if_fail (hook_id > 0);
+
+  signal = LOOKUP_SIGNAL_ID (signal_id);
+  g_return_if_fail (signal != NULL);
+
+  if (!signal->hook_list || !g_hook_destroy (signal->hook_list, hook_id))
+    g_warning ("gtk_signal_remove_emission_hook(): could not find hook (%u)", hook_id);
+  if (signal->hook_list && !signal->hook_list->hooks)
+    {
+      g_hook_list_clear (signal->hook_list);
+      g_free (signal->hook_list);
+      signal->hook_list = NULL;
+    }
+}
+
+static gboolean
+gtk_emission_hook_marshaller (GHook   *hook,
+			      gpointer data_p)
+{
+  gpointer *data = data_p;
+  GtkSignal *signal;
+  GtkEmissionHook func;
+
+  signal = data[0];
+  func = hook->func;
+
+  return func (data[1], signal->signal_id, hook->data);
+}
+
 static guint
 gtk_signal_connect_by_type (GtkObject	    *object,
 			    guint	     signal_id,
diff --git a/gtk/gtksignal.h b/gtk/gtksignal.h
index fa43c8c21..f9be8a870 100644
--- a/gtk/gtksignal.h
+++ b/gtk/gtksignal.h
@@ -33,13 +33,17 @@ extern "C" {
 #define GTK_SIGNAL_OFFSET(struct, field)	(GTK_STRUCT_OFFSET (struct, field))
   
   
-typedef void (*GtkSignalMarshal)    (GtkObject	    *object,
+typedef void    (*GtkSignalMarshal) (GtkObject	    *object,
 				     gpointer	     data,
 				     guint	     nparams,
 				     GtkArg	    *args,
 				     GtkType	    *arg_types,
 				     GtkType	     return_type);
-typedef void (*GtkSignalDestroy)    (gpointer	     data);
+typedef void    (*GtkSignalDestroy) (gpointer	     data);
+typedef gboolean (*GtkEmissionHook) (GtkObject	    *object,
+				     guint           signal_id,
+				     gpointer        data);
+
 
 typedef struct _GtkSignalQuery		GtkSignalQuery;
 
@@ -166,6 +170,16 @@ guint  gtk_signal_handler_pending_by_func (GtkObject	       *object,
 					   GtkSignalFunc	func,
 					   gpointer		data);
 void   gtk_signal_handlers_destroy	  (GtkObject	       *object);
+guint  gtk_signal_add_emission_hook	  (guint		signal_id,
+					   GtkEmissionHook	hook_func,
+					   gpointer       	data);
+guint  gtk_signal_add_emission_hook_full  (guint		signal_id,
+					   GtkEmissionHook	hook_func,
+					   gpointer       	data,
+					   GDestroyNotify	destroy);
+void   gtk_signal_remove_emission_hook	  (guint		signal_id,
+					   guint		hook_id);
+
 void   gtk_signal_set_funcs		  (GtkSignalMarshal	marshal_func,
 					   GtkSignalDestroy	destroy_func);
 
diff --git a/gtk/testgtk.c b/gtk/testgtk.c
index 1c23d15f9..57e6147eb 100644
--- a/gtk/testgtk.c
+++ b/gtk/testgtk.c
@@ -5261,7 +5261,7 @@ create_font_selection (void)
 
 static GtkWidget *dialog_window = NULL;
 
-void
+static void
 label_toggle (GtkWidget  *widget,
 	      GtkWidget **label)
 {
@@ -5281,7 +5281,7 @@ label_toggle (GtkWidget  *widget,
     gtk_widget_destroy (*label);
 }
 
-void
+static void
 create_dialog (void)
 {
   static GtkWidget *label;
@@ -5324,11 +5324,107 @@ create_dialog (void)
     gtk_widget_destroy (dialog_window);
 }
 
+/* Event Watcher
+ */
+static gboolean event_watcher_enter_id = 0;
+static gboolean event_watcher_leave_id = 0;
+
+static gboolean
+event_watcher (GtkObject      *object,
+	       guint           signal_id,
+	       gpointer        data)
+{
+  g_print ("Watch: \"%s\" emitted for %s\n",
+	   gtk_signal_name (signal_id),
+	   gtk_type_name (GTK_OBJECT_TYPE (object)));
+
+  return TRUE;
+}
+
+static void
+event_watcher_down (void)
+{
+  if (event_watcher_enter_id)
+    {
+      guint signal_id;
+
+      signal_id = gtk_signal_lookup ("enter_notify_event", GTK_TYPE_WIDGET);
+      gtk_signal_remove_emission_hook (signal_id, event_watcher_enter_id);
+      event_watcher_enter_id = 0;
+      signal_id = gtk_signal_lookup ("leave_notify_event", GTK_TYPE_WIDGET);
+      gtk_signal_remove_emission_hook (signal_id, event_watcher_leave_id);
+      event_watcher_leave_id = 0;
+    }
+}
+
+static void
+event_watcher_toggle (void)
+{
+  if (event_watcher_enter_id)
+    event_watcher_down ();
+  else
+    {
+      guint signal_id;
+
+      signal_id = gtk_signal_lookup ("enter_notify_event", GTK_TYPE_WIDGET);
+      event_watcher_enter_id = gtk_signal_add_emission_hook (signal_id, event_watcher, NULL);
+      signal_id = gtk_signal_lookup ("leave_notify_event", GTK_TYPE_WIDGET);
+      event_watcher_leave_id = gtk_signal_add_emission_hook (signal_id, event_watcher, NULL);
+    }
+}
+
+static void
+create_event_watcher (void)
+{
+  GtkWidget *button;
+
+  if (!dialog_window)
+    {
+      dialog_window = gtk_dialog_new ();
+
+      gtk_signal_connect (GTK_OBJECT (dialog_window), "destroy",
+			  GTK_SIGNAL_FUNC (gtk_widget_destroyed),
+			  &dialog_window);
+      gtk_signal_connect (GTK_OBJECT (dialog_window),
+			  "destroy",
+			  GTK_SIGNAL_FUNC (event_watcher_down),
+			  NULL);
+
+      gtk_window_set_title (GTK_WINDOW (dialog_window), "Event Watcher");
+      gtk_container_set_border_width (GTK_CONTAINER (dialog_window), 0);
+      gtk_widget_set_usize (dialog_window, 200, 110);
+
+      button = gtk_toggle_button_new_with_label ("Activate Watch");
+      gtk_signal_connect (GTK_OBJECT (button), "clicked",
+			  GTK_SIGNAL_FUNC (event_watcher_toggle),
+			  NULL);
+      gtk_container_set_border_width (GTK_CONTAINER (button), 10);
+      gtk_box_pack_start (GTK_BOX (GTK_DIALOG (dialog_window)->vbox), 
+			  button, TRUE, TRUE, 0);
+      gtk_widget_show (button);
+
+      button = gtk_button_new_with_label ("Close");
+      gtk_signal_connect (GTK_OBJECT (button), "clicked",
+			  GTK_SIGNAL_FUNC (gtk_widget_destroy),
+			  dialog_window);
+      GTK_WIDGET_SET_FLAGS (button, GTK_CAN_DEFAULT);
+      gtk_box_pack_start (GTK_BOX (GTK_DIALOG (dialog_window)->action_area),
+			  button, TRUE, TRUE, 0);
+      gtk_widget_grab_default (button);
+      gtk_widget_show (button);
+    }
+
+  if (!GTK_WIDGET_VISIBLE (dialog_window))
+    gtk_widget_show (dialog_window);
+  else
+    gtk_widget_destroy (dialog_window);
+}
+
 /*
  * GtkRange
  */
 
-void
+static void
 create_range_controls (void)
 {
   static GtkWidget *window = NULL;
@@ -8067,6 +8163,7 @@ create_main_window (void)
       { "dialog", create_dialog },
       /*      { "dnd", create_dnd }, */
       { "entry", create_entry },
+      { "event watcher", create_event_watcher },
       { "file selection", create_file_selection },
       { "font selection", create_font_selection },
       { "gamma curve", create_gamma_curve },
diff --git a/tests/testgtk.c b/tests/testgtk.c
index 1c23d15f9..57e6147eb 100644
--- a/tests/testgtk.c
+++ b/tests/testgtk.c
@@ -5261,7 +5261,7 @@ create_font_selection (void)
 
 static GtkWidget *dialog_window = NULL;
 
-void
+static void
 label_toggle (GtkWidget  *widget,
 	      GtkWidget **label)
 {
@@ -5281,7 +5281,7 @@ label_toggle (GtkWidget  *widget,
     gtk_widget_destroy (*label);
 }
 
-void
+static void
 create_dialog (void)
 {
   static GtkWidget *label;
@@ -5324,11 +5324,107 @@ create_dialog (void)
     gtk_widget_destroy (dialog_window);
 }
 
+/* Event Watcher
+ */
+static gboolean event_watcher_enter_id = 0;
+static gboolean event_watcher_leave_id = 0;
+
+static gboolean
+event_watcher (GtkObject      *object,
+	       guint           signal_id,
+	       gpointer        data)
+{
+  g_print ("Watch: \"%s\" emitted for %s\n",
+	   gtk_signal_name (signal_id),
+	   gtk_type_name (GTK_OBJECT_TYPE (object)));
+
+  return TRUE;
+}
+
+static void
+event_watcher_down (void)
+{
+  if (event_watcher_enter_id)
+    {
+      guint signal_id;
+
+      signal_id = gtk_signal_lookup ("enter_notify_event", GTK_TYPE_WIDGET);
+      gtk_signal_remove_emission_hook (signal_id, event_watcher_enter_id);
+      event_watcher_enter_id = 0;
+      signal_id = gtk_signal_lookup ("leave_notify_event", GTK_TYPE_WIDGET);
+      gtk_signal_remove_emission_hook (signal_id, event_watcher_leave_id);
+      event_watcher_leave_id = 0;
+    }
+}
+
+static void
+event_watcher_toggle (void)
+{
+  if (event_watcher_enter_id)
+    event_watcher_down ();
+  else
+    {
+      guint signal_id;
+
+      signal_id = gtk_signal_lookup ("enter_notify_event", GTK_TYPE_WIDGET);
+      event_watcher_enter_id = gtk_signal_add_emission_hook (signal_id, event_watcher, NULL);
+      signal_id = gtk_signal_lookup ("leave_notify_event", GTK_TYPE_WIDGET);
+      event_watcher_leave_id = gtk_signal_add_emission_hook (signal_id, event_watcher, NULL);
+    }
+}
+
+static void
+create_event_watcher (void)
+{
+  GtkWidget *button;
+
+  if (!dialog_window)
+    {
+      dialog_window = gtk_dialog_new ();
+
+      gtk_signal_connect (GTK_OBJECT (dialog_window), "destroy",
+			  GTK_SIGNAL_FUNC (gtk_widget_destroyed),
+			  &dialog_window);
+      gtk_signal_connect (GTK_OBJECT (dialog_window),
+			  "destroy",
+			  GTK_SIGNAL_FUNC (event_watcher_down),
+			  NULL);
+
+      gtk_window_set_title (GTK_WINDOW (dialog_window), "Event Watcher");
+      gtk_container_set_border_width (GTK_CONTAINER (dialog_window), 0);
+      gtk_widget_set_usize (dialog_window, 200, 110);
+
+      button = gtk_toggle_button_new_with_label ("Activate Watch");
+      gtk_signal_connect (GTK_OBJECT (button), "clicked",
+			  GTK_SIGNAL_FUNC (event_watcher_toggle),
+			  NULL);
+      gtk_container_set_border_width (GTK_CONTAINER (button), 10);
+      gtk_box_pack_start (GTK_BOX (GTK_DIALOG (dialog_window)->vbox), 
+			  button, TRUE, TRUE, 0);
+      gtk_widget_show (button);
+
+      button = gtk_button_new_with_label ("Close");
+      gtk_signal_connect (GTK_OBJECT (button), "clicked",
+			  GTK_SIGNAL_FUNC (gtk_widget_destroy),
+			  dialog_window);
+      GTK_WIDGET_SET_FLAGS (button, GTK_CAN_DEFAULT);
+      gtk_box_pack_start (GTK_BOX (GTK_DIALOG (dialog_window)->action_area),
+			  button, TRUE, TRUE, 0);
+      gtk_widget_grab_default (button);
+      gtk_widget_show (button);
+    }
+
+  if (!GTK_WIDGET_VISIBLE (dialog_window))
+    gtk_widget_show (dialog_window);
+  else
+    gtk_widget_destroy (dialog_window);
+}
+
 /*
  * GtkRange
  */
 
-void
+static void
 create_range_controls (void)
 {
   static GtkWidget *window = NULL;
@@ -8067,6 +8163,7 @@ create_main_window (void)
       { "dialog", create_dialog },
       /*      { "dnd", create_dnd }, */
       { "entry", create_entry },
+      { "event watcher", create_event_watcher },
       { "file selection", create_file_selection },
       { "font selection", create_font_selection },
       { "gamma curve", create_gamma_curve },