gtk2/gtk/gtktooltips.c

/* GTK - The GIMP Toolkit
 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/*
 * Modified by the GTK+ Team and others 1997-2000.  See the AUTHORS
 * file for a list of people on the GTK+ Team.  See the ChangeLog
 * files for a list of changes.  These files are distributed with
 * GTK+ at ftp://ftp.gtk.org/pub/gtk/. 
 */

#include <config.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>

#include "gtklabel.h"
#include "gtkmain.h"
#include "gtkmenuitem.h"
#include "gtkprivate.h"
#include "gtkwidget.h"
#include "gtkwindow.h"
#include "gtkstyle.h"
#include "gtktooltips.h"
#include "gtkintl.h"
#include "gtkalias.h"


#define DEFAULT_DELAY 500           /* Default delay in ms */
#define STICKY_DELAY 0              /* Delay before popping up next tip
                                     * if we're sticky
                                     */
#define STICKY_REVERT_DELAY 1000    /* Delay before sticky tooltips revert
				     * to normal
                                     */

static void gtk_tooltips_class_init        (GtkTooltipsClass *klass);
static void gtk_tooltips_init              (GtkTooltips      *tooltips);
static void gtk_tooltips_destroy           (GtkObject        *object);

static void gtk_tooltips_event_handler     (GtkWidget   *widget,
                                            GdkEvent    *event);
static void gtk_tooltips_widget_unmap      (GtkWidget   *widget,
                                            gpointer     data);
static void gtk_tooltips_widget_remove     (GtkWidget   *widget,
                                            gpointer     data);
static void gtk_tooltips_set_active_widget (GtkTooltips *tooltips,
                                            GtkWidget   *widget);
static gint gtk_tooltips_timeout           (gpointer     data);

static gint gtk_tooltips_paint_window      (GtkTooltips *tooltips);
static void gtk_tooltips_draw_tips         (GtkTooltips *tooltips);
static void gtk_tooltips_unset_tip_window  (GtkTooltips *tooltips);

static gboolean get_keyboard_mode          (GtkWidget   *widget);

static GtkObjectClass *parent_class;
static const gchar  tooltips_data_key[] = "_GtkTooltipsData";
static const gchar  tooltips_info_key[] = "_GtkTooltipsInfo";

GType
gtk_tooltips_get_type (void)
{
  static GType tooltips_type = 0;

  if (!tooltips_type)
    {
      static const GTypeInfo tooltips_info =
      {
	sizeof (GtkTooltipsClass),
	NULL,		/* base_init */
	NULL,		/* base_finalize */
	(GClassInitFunc) gtk_tooltips_class_init,
	NULL,		/* class_finalize */
	NULL,		/* class_data */
	sizeof (GtkTooltips),
	0,		/* n_preallocs */
	(GInstanceInitFunc) gtk_tooltips_init,
      };

      tooltips_type = g_type_register_static (GTK_TYPE_OBJECT, I_("GtkTooltips"),
					      &tooltips_info, 0);
    }

  return tooltips_type;
}

static void
gtk_tooltips_class_init (GtkTooltipsClass *class)
{
  GtkObjectClass *object_class;

  object_class = (GtkObjectClass*) class;

  parent_class = g_type_class_peek_parent (class);

  object_class->destroy = gtk_tooltips_destroy;
}

static void
gtk_tooltips_init (GtkTooltips *tooltips)
{
  tooltips->tip_window = NULL;
  tooltips->active_tips_data = NULL;
  tooltips->tips_data_list = NULL;
  
  tooltips->delay = DEFAULT_DELAY;
  tooltips->enabled = TRUE;
  tooltips->timer_tag = 0;
  tooltips->use_sticky_delay = FALSE;
  tooltips->last_popdown.tv_sec = -1;
  tooltips->last_popdown.tv_usec = -1;
}

GtkTooltips *
gtk_tooltips_new (void)
{
  return g_object_new (GTK_TYPE_TOOLTIPS, NULL);
}

static void
gtk_tooltips_destroy_data (GtkTooltipsData *tooltipsdata)
{
  g_free (tooltipsdata->tip_text);
  g_free (tooltipsdata->tip_private);

  g_signal_handlers_disconnect_by_func (tooltipsdata->widget,
					gtk_tooltips_event_handler,
					tooltipsdata);
  g_signal_handlers_disconnect_by_func (tooltipsdata->widget,
					gtk_tooltips_widget_unmap,
					tooltipsdata);
  g_signal_handlers_disconnect_by_func (tooltipsdata->widget,
					gtk_tooltips_widget_remove,
					tooltipsdata);

  g_object_set_data (G_OBJECT (tooltipsdata->widget), I_(tooltips_data_key), NULL);
  g_object_unref (tooltipsdata->widget);
  g_free (tooltipsdata);
}

static void
tip_window_display_closed (GdkDisplay  *display,
			   gboolean     was_error,
			   GtkTooltips *tooltips)
{
  gtk_tooltips_unset_tip_window (tooltips);
}

static void
disconnect_tip_window_display_closed (GtkTooltips *tooltips)
{
  g_signal_handlers_disconnect_by_func (gtk_widget_get_display (tooltips->tip_window),
					(gpointer) tip_window_display_closed,
					tooltips);
}

static void
gtk_tooltips_unset_tip_window (GtkTooltips *tooltips)
{
  if (tooltips->tip_window)
    {
      disconnect_tip_window_display_closed (tooltips);
      
      gtk_widget_destroy (tooltips->tip_window);
      tooltips->tip_window = NULL;
    }
}

static void
gtk_tooltips_destroy (GtkObject *object)
{
  GtkTooltips *tooltips = GTK_TOOLTIPS (object);
  GList *current;
  GtkTooltipsData *tooltipsdata;

  g_return_if_fail (tooltips != NULL);

  if (tooltips->timer_tag)
    {
      g_source_remove (tooltips->timer_tag);
      tooltips->timer_tag = 0;
    }

  if (tooltips->tips_data_list != NULL)
    {
      current = g_list_first (tooltips->tips_data_list);
      while (current != NULL)
	{
	  tooltipsdata = (GtkTooltipsData*) current->data;
	  current = current->next;
	  gtk_tooltips_widget_remove (tooltipsdata->widget, tooltipsdata);
	}
    }

  gtk_tooltips_unset_tip_window (tooltips);

  GTK_OBJECT_CLASS (parent_class)->destroy (object);
}

static void
gtk_tooltips_update_screen (GtkTooltips *tooltips,
			    gboolean     new_window)
{
  gboolean screen_changed = FALSE;
  
  if (tooltips->active_tips_data &&
      tooltips->active_tips_data->widget)
    {
      GdkScreen *screen = gtk_widget_get_screen (tooltips->active_tips_data->widget);

      screen_changed = (screen != gtk_widget_get_screen (tooltips->tip_window));

      if (screen_changed)
	{
	  if (!new_window)
	    disconnect_tip_window_display_closed (tooltips);
      
	  gtk_window_set_screen (GTK_WINDOW (tooltips->tip_window), screen);
	}
    }

  if (screen_changed || new_window)
    g_signal_connect (gtk_widget_get_display (tooltips->tip_window), "closed",
		      G_CALLBACK (tip_window_display_closed), tooltips);

}

void
gtk_tooltips_force_window (GtkTooltips *tooltips)
{
  g_return_if_fail (GTK_IS_TOOLTIPS (tooltips));

  if (!tooltips->tip_window)
    {
      tooltips->tip_window = gtk_window_new (GTK_WINDOW_POPUP);
      gtk_tooltips_update_screen (tooltips, TRUE);
      gtk_widget_set_app_paintable (tooltips->tip_window, TRUE);
      gtk_window_set_resizable (GTK_WINDOW (tooltips->tip_window), FALSE);
      gtk_widget_set_name (tooltips->tip_window, "gtk-tooltips");
      gtk_container_set_border_width (GTK_CONTAINER (tooltips->tip_window), 4);

      g_signal_connect_swapped (tooltips->tip_window,
				"expose_event",
				G_CALLBACK (gtk_tooltips_paint_window), 
				tooltips);

      tooltips->tip_label = gtk_label_new (NULL);
      gtk_label_set_line_wrap (GTK_LABEL (tooltips->tip_label), TRUE);
      gtk_misc_set_alignment (GTK_MISC (tooltips->tip_label), 0.5, 0.5);
      gtk_widget_show (tooltips->tip_label);
      
      gtk_container_add (GTK_CONTAINER (tooltips->tip_window), tooltips->tip_label);

      g_signal_connect (tooltips->tip_window,
			"destroy",
			G_CALLBACK (gtk_widget_destroyed),
			&tooltips->tip_window);
    }
}

void
gtk_tooltips_enable (GtkTooltips *tooltips)
{
  g_return_if_fail (tooltips != NULL);

  tooltips->enabled = TRUE;
}

void
gtk_tooltips_disable (GtkTooltips *tooltips)
{
  g_return_if_fail (tooltips != NULL);

  gtk_tooltips_set_active_widget (tooltips, NULL);

  tooltips->enabled = FALSE;
}

void
gtk_tooltips_set_delay (GtkTooltips *tooltips,
                        guint         delay)
{
  g_return_if_fail (tooltips != NULL);

  tooltips->delay = delay;
}

GtkTooltipsData*
gtk_tooltips_data_get (GtkWidget       *widget)
{
  g_return_val_if_fail (widget != NULL, NULL);

  return g_object_get_data (G_OBJECT (widget), tooltips_data_key);
}

void
gtk_tooltips_set_tip (GtkTooltips *tooltips,
		      GtkWidget   *widget,
		      const gchar *tip_text,
		      const gchar *tip_private)
{
  GtkTooltipsData *tooltipsdata;

  g_return_if_fail (GTK_IS_TOOLTIPS (tooltips));
  g_return_if_fail (widget != NULL);

  tooltipsdata = gtk_tooltips_data_get (widget);

  if (!tip_text)
    {
      if (tooltipsdata)
	gtk_tooltips_widget_remove (tooltipsdata->widget, tooltipsdata);
      return;
    }
  
  if (tooltips->active_tips_data 
      && tooltips->active_tips_data->widget == widget
      && GTK_WIDGET_DRAWABLE (tooltips->active_tips_data->widget))
    {
      g_free (tooltipsdata->tip_text);
      g_free (tooltipsdata->tip_private);

      tooltipsdata->tip_text = g_strdup (tip_text);
      tooltipsdata->tip_private = g_strdup (tip_private);
      
      gtk_tooltips_draw_tips (tooltips);
    }
  else 
    {
      g_object_ref (widget);
      
      if (tooltipsdata)
        gtk_tooltips_widget_remove (tooltipsdata->widget, tooltipsdata);
      
      tooltipsdata = g_new0 (GtkTooltipsData, 1);
      
      tooltipsdata->tooltips = tooltips;
      tooltipsdata->widget = widget;

      tooltipsdata->tip_text = g_strdup (tip_text);
      tooltipsdata->tip_private = g_strdup (tip_private);

      tooltips->tips_data_list = g_list_append (tooltips->tips_data_list,
                                                tooltipsdata);
      g_signal_connect_after (widget, "event-after",
                              G_CALLBACK (gtk_tooltips_event_handler),
			      tooltipsdata);

      g_object_set_data (G_OBJECT (widget), I_(tooltips_data_key),
                         tooltipsdata);

      g_signal_connect (widget, "unmap",
			G_CALLBACK (gtk_tooltips_widget_unmap),
			tooltipsdata);

      g_signal_connect (widget, "unrealize",
			G_CALLBACK (gtk_tooltips_widget_unmap),
			tooltipsdata);

      g_signal_connect (widget, "destroy",
                        G_CALLBACK (gtk_tooltips_widget_remove),
			tooltipsdata);
    }
}

static gint
gtk_tooltips_paint_window (GtkTooltips *tooltips)
{
  GtkRequisition req;

  gtk_widget_size_request (tooltips->tip_window, &req);
  gtk_paint_flat_box (tooltips->tip_window->style, tooltips->tip_window->window,
		      GTK_STATE_NORMAL, GTK_SHADOW_OUT, 
		      NULL, GTK_WIDGET(tooltips->tip_window), "tooltip",
		      0, 0, req.width, req.height);

  return FALSE;
}

static void
gtk_tooltips_draw_tips (GtkTooltips *tooltips)
{
  GtkRequisition requisition;
  GtkWidget *widget;
  gint x, y, w, h;
  GtkTooltipsData *data;
  gboolean keyboard_mode;
  GdkScreen *screen;
  GdkScreen *pointer_screen;
  gint monitor_num, px, py;
  GdkRectangle monitor;

  if (!tooltips->tip_window)
    gtk_tooltips_force_window (tooltips);
  else if (GTK_WIDGET_VISIBLE (tooltips->tip_window))
    g_get_current_time (&tooltips->last_popdown);

  gtk_widget_ensure_style (tooltips->tip_window);
  
  widget = tooltips->active_tips_data->widget;
  g_object_set_data (G_OBJECT (tooltips->tip_window), I_(tooltips_info_key),
                     tooltips);

  keyboard_mode = get_keyboard_mode (widget);

  gtk_tooltips_update_screen (tooltips, FALSE);
  
  screen = gtk_widget_get_screen (widget);

  data = tooltips->active_tips_data;

  gtk_label_set_text (GTK_LABEL (tooltips->tip_label), data->tip_text);

  gtk_widget_size_request (tooltips->tip_window, &requisition);
  w = requisition.width;
  h = requisition.height;

  gdk_window_get_origin (widget->window, &x, &y);
  if (GTK_WIDGET_NO_WINDOW (widget))
    {
      x += widget->allocation.x;
      y += widget->allocation.y;
    }

  x += widget->allocation.width / 2;
    
  if (!keyboard_mode)
    gdk_window_get_pointer (gdk_screen_get_root_window (screen),
			    &x, NULL, NULL);

  x -= (w / 2 + 4);

  gdk_display_get_pointer (gdk_screen_get_display (screen),
			   &pointer_screen, &px, &py, NULL);
  if (pointer_screen != screen) 
    {
      px = x;
      py = y;
    }
  monitor_num = gdk_screen_get_monitor_at_point (screen, px, py);
  gdk_screen_get_monitor_geometry (screen, monitor_num, &monitor);

  if ((x + w) > monitor.x + monitor.width)
    x -= (x + w) - (monitor.x + monitor.width);
  else if (x < monitor.x)
    x = monitor.x;

  if ((y + h + widget->allocation.height + 4) > monitor.y + monitor.height)
    y = y - h - 4;
  else
    y = y + widget->allocation.height + 4;

  gtk_window_move (GTK_WINDOW (tooltips->tip_window), x, y);
  gtk_widget_show (tooltips->tip_window);
}

static gint
gtk_tooltips_timeout (gpointer data)
{
  GtkTooltips *tooltips = (GtkTooltips *) data;

  GDK_THREADS_ENTER ();
  
  if (tooltips->active_tips_data != NULL &&
      GTK_WIDGET_DRAWABLE (tooltips->active_tips_data->widget))
    gtk_tooltips_draw_tips (tooltips);

  tooltips->timer_tag = 0;

  GDK_THREADS_LEAVE ();

  return FALSE;
}

static void
gtk_tooltips_set_active_widget (GtkTooltips *tooltips,
                                GtkWidget   *widget)
{
  if (tooltips->tip_window)
    {
      if (GTK_WIDGET_VISIBLE (tooltips->tip_window))
	g_get_current_time (&tooltips->last_popdown);
      gtk_widget_hide (tooltips->tip_window);
    }
  if (tooltips->timer_tag)
    {
      g_source_remove (tooltips->timer_tag);
      tooltips->timer_tag = 0;
    }
  
  tooltips->active_tips_data = NULL;
  
  if (widget)
    {
      GList *list;
      
      for (list = tooltips->tips_data_list; list; list = list->next)
	{
	  GtkTooltipsData *tooltipsdata;
	  
	  tooltipsdata = list->data;
	  
	  if (tooltipsdata->widget == widget &&
	      GTK_WIDGET_DRAWABLE (widget))
	    {
	      tooltips->active_tips_data = tooltipsdata;
	      break;
	    }
	}
    }
  else
    {
      tooltips->use_sticky_delay = FALSE;
    }
}

static void
gtk_tooltips_show_tip (GtkWidget *widget)
{
  GtkTooltipsData *tooltipsdata;

  tooltipsdata = gtk_tooltips_data_get (widget);

  if (tooltipsdata &&
      (!tooltipsdata->tooltips->active_tips_data ||
       tooltipsdata->tooltips->active_tips_data->widget != widget))
    {
      gtk_tooltips_set_active_widget (tooltipsdata->tooltips, widget);
      gtk_tooltips_draw_tips (tooltipsdata->tooltips);
    }
}

static void
gtk_tooltips_hide_tip (GtkWidget *widget)
{
  GtkTooltipsData *tooltipsdata;

  tooltipsdata = gtk_tooltips_data_get (widget);

  if (tooltipsdata &&
      (tooltipsdata->tooltips->active_tips_data &&
       tooltipsdata->tooltips->active_tips_data->widget == widget))
    gtk_tooltips_set_active_widget (tooltipsdata->tooltips, NULL);
}

static gboolean
gtk_tooltips_recently_shown (GtkTooltips *tooltips)
{
  GTimeVal now;
  glong msec;
  
  g_get_current_time (&now);
  msec = (now.tv_sec  - tooltips->last_popdown.tv_sec) * 1000 +
	  (now.tv_usec - tooltips->last_popdown.tv_usec) / 1000;
  return (msec < STICKY_REVERT_DELAY);
}

static gboolean
get_keyboard_mode (GtkWidget *widget)
{
  GtkWidget *toplevel = gtk_widget_get_toplevel (widget);
  if (GTK_IS_WINDOW (toplevel))
    return GPOINTER_TO_UINT (g_object_get_data (G_OBJECT (toplevel), "gtk-tooltips-keyboard-mode"));
  else
    return FALSE;
}

static void
start_keyboard_mode (GtkWidget *widget)
{
  GtkWidget *toplevel = gtk_widget_get_toplevel (widget);
  if (GTK_IS_WINDOW (toplevel))
    {
      GtkWidget *focus = GTK_WINDOW (toplevel)->focus_widget;

      g_object_set_data (G_OBJECT (toplevel), I_("gtk-tooltips-keyboard-mode"), GUINT_TO_POINTER (TRUE));

      if (focus)
	gtk_tooltips_show_tip (focus);
    }
}

static void
stop_keyboard_mode (GtkWidget *widget)
{
  GtkWidget *toplevel = gtk_widget_get_toplevel (widget);
  if (GTK_IS_WINDOW (toplevel))
    {
      GtkWidget *focus = GTK_WINDOW (toplevel)->focus_widget;
      if (focus)
	gtk_tooltips_hide_tip (focus);
      
      g_object_set_data (G_OBJECT (toplevel), I_("gtk-tooltips-keyboard-mode"), GUINT_TO_POINTER (FALSE));
    }
}

static gboolean
tooltips_enabled (GtkTooltips *tooltips, GtkWidget *w)
{
  GtkSettings *settings;
  gboolean touchscreen;

  if (!tooltips->enabled)
    return FALSE;

  settings = gtk_widget_get_settings (w);
  g_object_get (settings, "gtk-touchscreen-mode", &touchscreen, NULL);
  
  return !touchscreen;
}

static void
gtk_tooltips_start_delay (GtkTooltips *tooltips,
			  GtkWidget   *widget)
{
  GtkTooltipsData *old_tips_data;
  
  old_tips_data = tooltips->active_tips_data;
  if (tooltips_enabled (tooltips, widget) &&
      (!old_tips_data || old_tips_data->widget != widget))
    {
      guint delay;
      
      gtk_tooltips_set_active_widget (tooltips, widget);
      
      if (tooltips->use_sticky_delay &&
	  gtk_tooltips_recently_shown (tooltips))
	delay = STICKY_DELAY;
      else
	delay = tooltips->delay;
      tooltips->timer_tag = g_timeout_add (delay,
					   gtk_tooltips_timeout,
					   (gpointer) tooltips);
    }
}

static void
gtk_tooltips_event_handler (GtkWidget *widget,
                            GdkEvent  *event)
{
  GtkTooltips *tooltips;
  GtkTooltipsData *old_tips_data;
  GtkWidget *event_widget;
  gboolean keyboard_mode = get_keyboard_mode (widget);

  if ((event->type == GDK_LEAVE_NOTIFY || event->type == GDK_ENTER_NOTIFY) &&
      event->crossing.detail == GDK_NOTIFY_INFERIOR)
    return;

  old_tips_data = gtk_tooltips_data_get (widget);
  tooltips = old_tips_data->tooltips;

  if (keyboard_mode)
    {
      switch (event->type)
	{
	case GDK_FOCUS_CHANGE:
	  if (event->focus_change.in)
	    gtk_tooltips_show_tip (widget);
	  else
	    gtk_tooltips_hide_tip (widget);
	  break;
	default:
	  break;
	}
    }
  else
    {
      if (event->type != GDK_KEY_PRESS && event->type != GDK_KEY_RELEASE)
	{
	  event_widget = gtk_get_event_widget (event);
	  if (event_widget != widget)
	    return;
	}
  
      switch (event->type)
	{
	case GDK_EXPOSE:
	  /* do nothing */
	  break;
	case GDK_ENTER_NOTIFY:
	  if (!(GTK_IS_MENU_ITEM (widget) && GTK_MENU_ITEM (widget)->submenu))
	    gtk_tooltips_start_delay (tooltips, widget);
	  break;
	  
	case GDK_LEAVE_NOTIFY:
	  {
	    gboolean use_sticky_delay;
	    
	    use_sticky_delay = tooltips->tip_window &&
	      GTK_WIDGET_VISIBLE (tooltips->tip_window);
	    gtk_tooltips_set_active_widget (tooltips, NULL);
	    tooltips->use_sticky_delay = use_sticky_delay;
	  }
	  break;

	case GDK_MOTION_NOTIFY:
	  /* Handle menu items specially ... pend popup for each motion
	   * on other widgets, we ignore motion.
	   */
	  if (GTK_IS_MENU_ITEM (widget) && !GTK_MENU_ITEM (widget)->submenu)
	    {
	      /* Completely evil hack to make sure we get the LEAVE_NOTIFY
	       */
	      GTK_PRIVATE_SET_FLAG (widget, GTK_LEAVE_PENDING);
	      gtk_tooltips_set_active_widget (tooltips, NULL);
	      gtk_tooltips_start_delay (tooltips, widget);
	      break;
	    }
	  break;		/* ignore */
	case GDK_BUTTON_PRESS:
	case GDK_BUTTON_RELEASE:
	case GDK_KEY_PRESS:
	case GDK_KEY_RELEASE:
	case GDK_PROXIMITY_IN:
	case GDK_SCROLL:
	  gtk_tooltips_set_active_widget (tooltips, NULL);
	  break;
	default:
	  break;
	}
    }
}

static void
gtk_tooltips_widget_unmap (GtkWidget *widget,
			   gpointer   data)
{
  GtkTooltipsData *tooltipsdata = (GtkTooltipsData *)data;
  GtkTooltips *tooltips = tooltipsdata->tooltips;
  
  if (tooltips->active_tips_data &&
      (tooltips->active_tips_data->widget == widget))
    gtk_tooltips_set_active_widget (tooltips, NULL);
}

static void
gtk_tooltips_widget_remove (GtkWidget *widget,
			    gpointer   data)
{
  GtkTooltipsData *tooltipsdata = (GtkTooltipsData*) data;
  GtkTooltips *tooltips = tooltipsdata->tooltips;

  gtk_tooltips_widget_unmap (widget, data);
  tooltips->tips_data_list = g_list_remove (tooltips->tips_data_list,
					    tooltipsdata);
  gtk_tooltips_destroy_data (tooltipsdata);
}

void
_gtk_tooltips_toggle_keyboard_mode (GtkWidget *widget)
{
  if (get_keyboard_mode (widget))
    stop_keyboard_mode (widget);
  else
    start_keyboard_mode (widget);
}

/**
 * gtk_tooltips_get_info_from_tip_window:
 * @tip_window: a #GtkWindow 
 * @tooltips: the return location for the tooltips which are displayed 
 *    in @tip_window, or %NULL
 * @current_widget: the return location for the widget whose tooltips 
 *    are displayed, or %NULL
 * 
 * Determines the tooltips and the widget they belong to from the window in 
 * which they are displayed. 
 *
 * This function is mostly intended for use by accessibility technologies;
 * applications should have little use for it.
 * 
 * Return value: %TRUE if @tip_window is displaying tooltips, otherwise %FALSE.
 *
 * Since: 2.4
 **/
gboolean
gtk_tooltips_get_info_from_tip_window (GtkWindow    *tip_window,
                                       GtkTooltips **tooltips,
                                       GtkWidget   **current_widget)
{
  GtkTooltips  *current_tooltips;  
  gboolean has_tips;

  g_return_val_if_fail (GTK_IS_WINDOW (tip_window), FALSE);

  current_tooltips = g_object_get_data (G_OBJECT (tip_window), tooltips_info_key);

  has_tips = current_tooltips != NULL;

  if (tooltips)
    *tooltips = current_tooltips;
  if (current_widget)
    *current_widget = has_tips ? current_tooltips->active_tips_data->widget : NULL;

  return has_tips;
}

#define __GTK_TOOLTIPS_C__
#include "gtkaliasdef.c"