/* 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 "gtkviewport.h"

#include "gtkintl.h"

#include "gtkmarshalers.h"

#include "gtkprivate.h"

#include "gtkalias.h"

/**

 * SECTION:gtkviewport

 * @Short_description: An adapter which makes widgets scrollable

 * @Title: GtkViewport

 * @See_also:#GtkScrolledWindow, #GtkAdjustment

 *

 * The #GtkViewport widget acts as an adaptor class, implementing

 * scrollability for child widgets that lack their own scrolling

 * capabilities. Use #GtkViewport to scroll child widgets such as

 * #GtkTable, #GtkBox, and so on.

 *

 * If a widget has native scrolling abilities, such as #GtkTextView,

 * #GtkTreeView or #GtkIconview, it can be added to a #GtkScrolledWindow

 * with gtk_container_add(). If a widget does not, you must first add the

 * widget to a #GtkViewport, then add the viewport to the scrolled window.

 * The convenience function gtk_scrolled_window_add_with_viewport() does

 * exactly this, so you can ignore the presence of the viewport.

 */

enum {

  PROP_0,

  PROP_HADJUSTMENT,

  PROP_VADJUSTMENT,

  PROP_SHADOW_TYPE

};

static void gtk_viewport_finalize                 (GObject          *object);

static void gtk_viewport_destroy                  (GtkObject        *object);

static void gtk_viewport_set_property             (GObject         *object,

						   guint            prop_id,

						   const GValue    *value,

						   GParamSpec      *pspec);

static void gtk_viewport_get_property             (GObject         *object,

						   guint            prop_id,

						   GValue          *value,

						   GParamSpec      *pspec);

static void gtk_viewport_set_scroll_adjustments	  (GtkViewport	    *viewport,

						   GtkAdjustment    *hadjustment,

						   GtkAdjustment    *vadjustment);

static void gtk_viewport_realize                  (GtkWidget        *widget);

static void gtk_viewport_unrealize                (GtkWidget        *widget);

static void gtk_viewport_paint                    (GtkWidget        *widget,

						   GdkRectangle     *area);

static gint gtk_viewport_expose                   (GtkWidget        *widget,

						   GdkEventExpose   *event);

static void gtk_viewport_add                      (GtkContainer     *container,

						   GtkWidget        *widget);

static void gtk_viewport_size_request             (GtkWidget        *widget,

						   GtkRequisition   *requisition);

static void gtk_viewport_size_allocate            (GtkWidget        *widget,

						   GtkAllocation    *allocation);

static void gtk_viewport_adjustment_value_changed (GtkAdjustment    *adjustment,

						   gpointer          data);

static void gtk_viewport_style_set                (GtkWidget *widget,

			                           GtkStyle  *previous_style);

G_DEFINE_TYPE (GtkViewport, gtk_viewport, GTK_TYPE_BIN)

static void

gtk_viewport_class_init (GtkViewportClass *class)

{

  GtkObjectClass *object_class;

  GObjectClass   *gobject_class;

  GtkWidgetClass *widget_class;

  GtkContainerClass *container_class;

  object_class = (GtkObjectClass*) class;

  gobject_class = G_OBJECT_CLASS (class);

  widget_class = (GtkWidgetClass*) class;

  container_class = (GtkContainerClass*) class;

  gobject_class->finalize = gtk_viewport_finalize;

  gobject_class->set_property = gtk_viewport_set_property;

  gobject_class->get_property = gtk_viewport_get_property;

  object_class->destroy = gtk_viewport_destroy;

  widget_class->realize = gtk_viewport_realize;

  widget_class->unrealize = gtk_viewport_unrealize;

  widget_class->expose_event = gtk_viewport_expose;

  widget_class->size_request = gtk_viewport_size_request;

  widget_class->size_allocate = gtk_viewport_size_allocate;

  widget_class->style_set = gtk_viewport_style_set;

  container_class->add = gtk_viewport_add;

  class->set_scroll_adjustments = gtk_viewport_set_scroll_adjustments;

  g_object_class_install_property (gobject_class,

                                   PROP_HADJUSTMENT,

                                   g_param_spec_object ("hadjustment",

							P_("Horizontal adjustment"),

							P_("The GtkAdjustment that determines the values of the horizontal position for this viewport"),

                                                        GTK_TYPE_ADJUSTMENT,

                                                        GTK_PARAM_READWRITE | G_PARAM_CONSTRUCT));

  g_object_class_install_property (gobject_class,

                                   PROP_VADJUSTMENT,

                                   g_param_spec_object ("vadjustment",

							P_("Vertical adjustment"),

							P_("The GtkAdjustment that determines the values of the vertical position for this viewport"),

                                                        GTK_TYPE_ADJUSTMENT,

                                                        GTK_PARAM_READWRITE | G_PARAM_CONSTRUCT));

  g_object_class_install_property (gobject_class,

                                   PROP_SHADOW_TYPE,

                                   g_param_spec_enum ("shadow-type",

						      P_("Shadow type"),

						      P_("Determines how the shadowed box around the viewport is drawn"),

						      GTK_TYPE_SHADOW_TYPE,

						      GTK_SHADOW_IN,

						      GTK_PARAM_READWRITE));

  /**

   * GtkViewport::set-scroll-adjustments

   * @horizontal: the horizontal #GtkAdjustment

   * @vertical: the vertical #GtkAdjustment

   *

   * Set the scroll adjustments for the viewport. Usually scrolled containers

   * like #GtkScrolledWindow will emit this signal to connect two instances

   * of #GtkScrollbar to the scroll directions of the #GtkViewport.

   */

  widget_class->set_scroll_adjustments_signal =

    g_signal_new (I_("set-scroll-adjustments"),

		  G_OBJECT_CLASS_TYPE (gobject_class),

		  G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION,

		  G_STRUCT_OFFSET (GtkViewportClass, set_scroll_adjustments),

		  NULL, NULL,

		  _gtk_marshal_VOID__OBJECT_OBJECT,

		  G_TYPE_NONE, 2,

		  GTK_TYPE_ADJUSTMENT,

		  GTK_TYPE_ADJUSTMENT);

}

static void

gtk_viewport_set_property (GObject         *object,

			   guint            prop_id,

			   const GValue    *value,

			   GParamSpec      *pspec)

{

  GtkViewport *viewport;

  viewport = GTK_VIEWPORT (object);

  switch (prop_id)

    {

    case PROP_HADJUSTMENT:

      gtk_viewport_set_hadjustment (viewport, g_value_get_object (value));

      break;

    case PROP_VADJUSTMENT:

      gtk_viewport_set_vadjustment (viewport, g_value_get_object (value));

      break;

    case PROP_SHADOW_TYPE:

      gtk_viewport_set_shadow_type (viewport, g_value_get_enum (value));

      break;

    default:

      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);

      break;

    }

}

static void

gtk_viewport_get_property (GObject         *object,

			   guint            prop_id,

			   GValue          *value,

			   GParamSpec      *pspec)

{

  GtkViewport *viewport;

  viewport = GTK_VIEWPORT (object);

  switch (prop_id)

    {

    case PROP_HADJUSTMENT:

      g_value_set_object (value, viewport->hadjustment);

      break;

    case PROP_VADJUSTMENT:

      g_value_set_object (value, viewport->vadjustment);

      break;

    case PROP_SHADOW_TYPE:

      g_value_set_enum (value, viewport->shadow_type);

      break;

    default:

      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);

      break;

    }

}

static void

gtk_viewport_init (GtkViewport *viewport)

{

  gtk_widget_set_has_window (GTK_WIDGET (viewport), TRUE);

  gtk_widget_set_redraw_on_allocate (GTK_WIDGET (viewport), FALSE);

  gtk_container_set_resize_mode (GTK_CONTAINER (viewport), GTK_RESIZE_QUEUE);

  viewport->shadow_type = GTK_SHADOW_IN;

  viewport->view_window = NULL;

  viewport->bin_window = NULL;

  viewport->hadjustment = NULL;

  viewport->vadjustment = NULL;

}

/**

 * gtk_viewport_new:

 * @hadjustment: horizontal adjustment.

 * @vadjustment: vertical adjustment.

 * @returns: a new #GtkViewport.

 *

 * Creates a new #GtkViewport with the given adjustments.

 *

 **/

GtkWidget*

gtk_viewport_new (GtkAdjustment *hadjustment,

		  GtkAdjustment *vadjustment)

{

  GtkWidget *viewport;

  viewport = g_object_new (GTK_TYPE_VIEWPORT,

			     "hadjustment", hadjustment,

			     "vadjustment", vadjustment,

			     NULL);

  return viewport;

}

#define ADJUSTMENT_POINTER(viewport, orientation)         \

  (((orientation) == GTK_ORIENTATION_HORIZONTAL) ?        \

     &(viewport)->hadjustment : &(viewport)->vadjustment)

static void

viewport_disconnect_adjustment (GtkViewport    *viewport,

				GtkOrientation  orientation)

{

  GtkAdjustment **adjustmentp = ADJUSTMENT_POINTER (viewport, orientation);

  if (*adjustmentp)

    {

      g_signal_handlers_disconnect_by_func (*adjustmentp,

					    gtk_viewport_adjustment_value_changed,

					    viewport);

      g_object_unref (*adjustmentp);

      *adjustmentp = NULL;

    }

}

static void

gtk_viewport_finalize (GObject *object)

{

  GtkViewport *viewport = GTK_VIEWPORT (object);

  viewport_disconnect_adjustment (viewport, GTK_ORIENTATION_HORIZONTAL);

  viewport_disconnect_adjustment (viewport, GTK_ORIENTATION_VERTICAL);

  G_OBJECT_CLASS (gtk_viewport_parent_class)->finalize (object);

}

static void

gtk_viewport_destroy (GtkObject *object)

{

  GtkViewport *viewport = GTK_VIEWPORT (object);

  viewport_disconnect_adjustment (viewport, GTK_ORIENTATION_HORIZONTAL);

  viewport_disconnect_adjustment (viewport, GTK_ORIENTATION_VERTICAL);

  GTK_OBJECT_CLASS (gtk_viewport_parent_class)->destroy (object);

}

/**

 * gtk_viewport_get_hadjustment:

 * @viewport: a #GtkViewport.

 *

 * Returns the horizontal adjustment of the viewport.

 *

 * Return value: (transfer none): the horizontal adjustment of @viewport.

 **/

GtkAdjustment*

gtk_viewport_get_hadjustment (GtkViewport *viewport)

{

  g_return_val_if_fail (GTK_IS_VIEWPORT (viewport), NULL);

  if (!viewport->hadjustment)

    gtk_viewport_set_hadjustment (viewport, NULL);

  return viewport->hadjustment;

}

/**

 * gtk_viewport_get_vadjustment:

 * @viewport: a #GtkViewport.

 * 

 * Returns the vertical adjustment of the viewport.

 *

 * Return value: (transfer none): the vertical adjustment of @viewport.

 **/

GtkAdjustment*

gtk_viewport_get_vadjustment (GtkViewport *viewport)

{

  g_return_val_if_fail (GTK_IS_VIEWPORT (viewport), NULL);

  if (!viewport->vadjustment)

    gtk_viewport_set_vadjustment (viewport, NULL);

  return viewport->vadjustment;

}

static void

viewport_get_view_allocation (GtkViewport   *viewport,

			      GtkAllocation *view_allocation)

{

  GtkWidget *widget = GTK_WIDGET (viewport);

  GtkAllocation *allocation = &widget->allocation;

  gint border_width = GTK_CONTAINER (viewport)->border_width;

  view_allocation->x = 0;

  view_allocation->y = 0;

  if (viewport->shadow_type != GTK_SHADOW_NONE)

    {

      view_allocation->x = widget->style->xthickness;

      view_allocation->y = widget->style->ythickness;

    }

  view_allocation->width = MAX (1, allocation->width - view_allocation->x * 2 - border_width * 2);

  view_allocation->height = MAX (1, allocation->height - view_allocation->y * 2 - border_width * 2);

}

static void

viewport_reclamp_adjustment (GtkAdjustment *adjustment,

			     gboolean      *value_changed)

{

  gdouble value = adjustment->value;

  value = CLAMP (value, 0, adjustment->upper - adjustment->page_size);

  if (value != adjustment->value)

    {

      adjustment->value = value;

      if (value_changed)

	*value_changed = TRUE;

    }

  else if (value_changed)

    *value_changed = FALSE;

}

static void

viewport_set_hadjustment_values (GtkViewport *viewport,

				 gboolean    *value_changed)

{

  GtkBin *bin = GTK_BIN (viewport);

  GtkAllocation view_allocation;

  GtkAdjustment *hadjustment = gtk_viewport_get_hadjustment (viewport);

  gdouble old_page_size;

  gdouble old_upper;

  gdouble old_value;

  viewport_get_view_allocation (viewport, &view_allocation);  

  old_page_size = hadjustment->page_size;

  old_upper = hadjustment->upper;

  old_value = hadjustment->value;

  hadjustment->page_size = view_allocation.width;

  hadjustment->step_increment = view_allocation.width * 0.1;

  hadjustment->page_increment = view_allocation.width * 0.9;

  hadjustment->lower = 0;

  if (bin->child && gtk_widget_get_visible (bin->child))

    {

      GtkRequisition child_requisition;

      gtk_widget_get_child_requisition (bin->child, &child_requisition);

      hadjustment->upper = MAX (child_requisition.width, view_allocation.width);

    }

  else

    hadjustment->upper = view_allocation.width;

  if (gtk_widget_get_direction (GTK_WIDGET (viewport)) == GTK_TEXT_DIR_RTL) 

    {

      gdouble dist = old_upper - (old_value + old_page_size);

      hadjustment->value = hadjustment->upper - dist - hadjustment->page_size;

      viewport_reclamp_adjustment (hadjustment, value_changed);

      *value_changed = (old_value != hadjustment->value);

    }

  else

    viewport_reclamp_adjustment (hadjustment, value_changed);

}

static void

viewport_set_vadjustment_values (GtkViewport *viewport,

				 gboolean    *value_changed)

{

  GtkBin *bin = GTK_BIN (viewport);

  GtkAllocation view_allocation;

  GtkAdjustment *vadjustment = gtk_viewport_get_vadjustment (viewport);

  viewport_get_view_allocation (viewport, &view_allocation);  

  vadjustment->page_size = view_allocation.height;

  vadjustment->step_increment = view_allocation.height * 0.1;

  vadjustment->page_increment = view_allocation.height * 0.9;

  vadjustment->lower = 0;

  if (bin->child && gtk_widget_get_visible (bin->child))

    {

      GtkRequisition child_requisition;

      gtk_widget_get_child_requisition (bin->child, &child_requisition);

      vadjustment->upper = MAX (child_requisition.height, view_allocation.height);

    }

  else

    vadjustment->upper = view_allocation.height;

  viewport_reclamp_adjustment (vadjustment, value_changed);

}

static void

viewport_set_adjustment (GtkViewport    *viewport,

			 GtkOrientation  orientation,

			 GtkAdjustment  *adjustment)

{

  GtkAdjustment **adjustmentp = ADJUSTMENT_POINTER (viewport, orientation);

  gboolean value_changed;

  if (adjustment && adjustment == *adjustmentp)

    return;

  if (!adjustment)

    adjustment = GTK_ADJUSTMENT (gtk_adjustment_new (0.0, 0.0, 0.0,

						     0.0, 0.0, 0.0));

  viewport_disconnect_adjustment (viewport, orientation);

  *adjustmentp = adjustment;

  g_object_ref_sink (adjustment);

  if (orientation == GTK_ORIENTATION_HORIZONTAL)

    viewport_set_hadjustment_values (viewport, &value_changed);

  else

    viewport_set_vadjustment_values (viewport, &value_changed);

  g_signal_connect (adjustment, "value-changed",

		    G_CALLBACK (gtk_viewport_adjustment_value_changed),

		    viewport);

  gtk_adjustment_changed (adjustment);

  if (value_changed)

    gtk_adjustment_value_changed (adjustment);

  else

    gtk_viewport_adjustment_value_changed (adjustment, viewport);

}

/**

 * gtk_viewport_set_hadjustment:

 * @viewport: a #GtkViewport.

 * @adjustment: (allow-none): a #GtkAdjustment.

 *

 * Sets the horizontal adjustment of the viewport.

 **/

void

gtk_viewport_set_hadjustment (GtkViewport   *viewport,

			      GtkAdjustment *adjustment)

{

  g_return_if_fail (GTK_IS_VIEWPORT (viewport));

  if (adjustment)

    g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));

  viewport_set_adjustment (viewport, GTK_ORIENTATION_HORIZONTAL, adjustment);

  g_object_notify (G_OBJECT (viewport), "hadjustment");

}

/**

 * gtk_viewport_set_vadjustment:

 * @viewport: a #GtkViewport.

 * @adjustment: (allow-none): a #GtkAdjustment.

 *

 * Sets the vertical adjustment of the viewport.

 **/

void

gtk_viewport_set_vadjustment (GtkViewport   *viewport,

			      GtkAdjustment *adjustment)

{

  g_return_if_fail (GTK_IS_VIEWPORT (viewport));

  if (adjustment)

    g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));

  viewport_set_adjustment (viewport, GTK_ORIENTATION_VERTICAL, adjustment);

  g_object_notify (G_OBJECT (viewport), "vadjustment");

}

static void

gtk_viewport_set_scroll_adjustments (GtkViewport      *viewport,

				     GtkAdjustment    *hadjustment,

				     GtkAdjustment    *vadjustment)

{

  gtk_viewport_set_hadjustment (viewport, hadjustment);

  gtk_viewport_set_vadjustment (viewport, vadjustment);

}

/** 

 * gtk_viewport_set_shadow_type:

 * @viewport: a #GtkViewport.

 * @type: the new shadow type.

 *

 * Sets the shadow type of the viewport.

 **/ 

void

gtk_viewport_set_shadow_type (GtkViewport   *viewport,

			      GtkShadowType  type)

{

  g_return_if_fail (GTK_IS_VIEWPORT (viewport));

  if ((GtkShadowType) viewport->shadow_type != type)

    {

      viewport->shadow_type = type;

      if (gtk_widget_get_visible (GTK_WIDGET (viewport)))

	{

	  gtk_widget_size_allocate (GTK_WIDGET (viewport), &(GTK_WIDGET (viewport)->allocation));

	  gtk_widget_queue_draw (GTK_WIDGET (viewport));

	}

      g_object_notify (G_OBJECT (viewport), "shadow-type");

    }

}

/**

 * gtk_viewport_get_shadow_type:

 * @viewport: a #GtkViewport

 *

 * Gets the shadow type of the #GtkViewport. See

 * gtk_viewport_set_shadow_type().

 * Return value: the shadow type 

 **/

GtkShadowType

gtk_viewport_get_shadow_type (GtkViewport *viewport)

{

  g_return_val_if_fail (GTK_IS_VIEWPORT (viewport), GTK_SHADOW_NONE);

  return viewport->shadow_type;

}

/**

 * gtk_viewport_get_bin_window:

 * @viewport: a #GtkViewport

 *

 * Gets the bin window of the #GtkViewport.

 *

 * Return value: (transfer none): a #GdkWindow

 *

 * Since: 2.20

 **/

GdkWindow*

gtk_viewport_get_bin_window (GtkViewport *viewport)

{

  g_return_val_if_fail (GTK_IS_VIEWPORT (viewport), NULL);

  return viewport->bin_window;

}

/**

 * gtk_viewport_get_view_window:

 * @viewport: a #GtkViewport

 *

 * Gets the view window of the #GtkViewport.

 *

 * Return value: (transfer none): a #GdkWindow

 *

 * Since: 2.22

 **/

GdkWindow*

gtk_viewport_get_view_window (GtkViewport *viewport)

{

  g_return_val_if_fail (GTK_IS_VIEWPORT (viewport), NULL);

  return viewport->view_window;

}

static void

gtk_viewport_realize (GtkWidget *widget)

{

  GtkViewport *viewport = GTK_VIEWPORT (widget);

  GtkBin *bin = GTK_BIN (widget);

  GtkAdjustment *hadjustment = gtk_viewport_get_hadjustment (viewport);

  GtkAdjustment *vadjustment = gtk_viewport_get_vadjustment (viewport);

  gint border_width = GTK_CONTAINER (widget)->border_width;

  GtkAllocation view_allocation;

  GdkWindowAttr attributes;

  gint attributes_mask;

  gint event_mask;

  gtk_widget_set_realized (widget, TRUE);

  attributes.x = widget->allocation.x + border_width;

  attributes.y = widget->allocation.y + border_width;

  attributes.width = widget->allocation.width - border_width * 2;

  attributes.height = widget->allocation.height - border_width * 2;

  attributes.window_type = GDK_WINDOW_CHILD;

  attributes.wclass = GDK_INPUT_OUTPUT;

  attributes.visual = gtk_widget_get_visual (widget);

  attributes.colormap = gtk_widget_get_colormap (widget);

  event_mask = gtk_widget_get_events (widget) | GDK_EXPOSURE_MASK;

  /* We select on button_press_mask so that button 4-5 scrolls are trapped.

   */

  attributes.event_mask = event_mask | GDK_BUTTON_PRESS_MASK;

  attributes_mask = GDK_WA_X | GDK_WA_Y | GDK_WA_VISUAL | GDK_WA_COLORMAP;

  widget->window = gdk_window_new (gtk_widget_get_parent_window (widget),

				   &attributes, attributes_mask);

  gdk_window_set_user_data (widget->window, viewport);

  viewport_get_view_allocation (viewport, &view_allocation);

  attributes.x = view_allocation.x;

  attributes.y = view_allocation.y;

  attributes.width = view_allocation.width;

  attributes.height = view_allocation.height;

  attributes.event_mask = 0;

  viewport->view_window = gdk_window_new (widget->window, &attributes, attributes_mask);

  gdk_window_set_user_data (viewport->view_window, viewport);

  gdk_window_set_back_pixmap (viewport->view_window, NULL, FALSE);

  attributes.x = - hadjustment->value;

  attributes.y = - vadjustment->value;

  attributes.width = hadjustment->upper;

  attributes.height = vadjustment->upper;

  attributes.event_mask = event_mask;

  viewport->bin_window = gdk_window_new (viewport->view_window, &attributes, attributes_mask);

  gdk_window_set_user_data (viewport->bin_window, viewport);

  if (bin->child)

    gtk_widget_set_parent_window (bin->child, viewport->bin_window);

  widget->style = gtk_style_attach (widget->style, widget->window);

  gtk_style_set_background (widget->style, widget->window, GTK_STATE_NORMAL);

  gtk_style_set_background (widget->style, viewport->bin_window, GTK_STATE_NORMAL);

  /* Call paint here to allow a theme to set the background without flashing

   */

  gtk_paint_flat_box(widget->style, viewport->bin_window, GTK_STATE_NORMAL,

		     GTK_SHADOW_NONE,

		     NULL, widget, "viewportbin",

		     0, 0, -1, -1);

  gdk_window_show (viewport->bin_window);

  gdk_window_show (viewport->view_window);

}

static void

gtk_viewport_unrealize (GtkWidget *widget)

{

  GtkViewport *viewport = GTK_VIEWPORT (widget);

  gdk_window_set_user_data (viewport->view_window, NULL);

  gdk_window_destroy (viewport->view_window);

  viewport->view_window = NULL;

  gdk_window_set_user_data (viewport->bin_window, NULL);

  gdk_window_destroy (viewport->bin_window);

  viewport->bin_window = NULL;

  GTK_WIDGET_CLASS (gtk_viewport_parent_class)->unrealize (widget);

}

static void

gtk_viewport_paint (GtkWidget    *widget,

		    GdkRectangle *area)

{

  if (gtk_widget_is_drawable (widget))

    {

      GtkViewport *viewport = GTK_VIEWPORT (widget);

      gtk_paint_shadow (widget->style, widget->window,

			GTK_STATE_NORMAL, viewport->shadow_type,

			area, widget, "viewport",

			0, 0, -1, -1);

    }

}

static gint

gtk_viewport_expose (GtkWidget      *widget,

		     GdkEventExpose *event)

{

  GtkViewport *viewport;

  if (gtk_widget_is_drawable (widget))

    {

      viewport = GTK_VIEWPORT (widget);

      if (event->window == widget->window)

	gtk_viewport_paint (widget, &event->area);

      else if (event->window == viewport->bin_window)

	{

	  gtk_paint_flat_box(widget->style, viewport->bin_window, 

			     GTK_STATE_NORMAL, GTK_SHADOW_NONE,

			     &event->area, widget, "viewportbin",

			     0, 0, -1, -1);

	  GTK_WIDGET_CLASS (gtk_viewport_parent_class)->expose_event (widget, event);

	}

    }

  return FALSE;

}

static void

gtk_viewport_add (GtkContainer *container,

		  GtkWidget    *child)

{

  GtkBin *bin = GTK_BIN (container);

  g_return_if_fail (bin->child == NULL);

  gtk_widget_set_parent_window (child, GTK_VIEWPORT (bin)->bin_window);

  GTK_CONTAINER_CLASS (gtk_viewport_parent_class)->add (container, child);

}

static void

gtk_viewport_size_request (GtkWidget      *widget,

			   GtkRequisition *requisition)

{

  GtkBin *bin = GTK_BIN (widget);

  GtkRequisition child_requisition;

  requisition->width = GTK_CONTAINER (widget)->border_width;

  requisition->height = GTK_CONTAINER (widget)->border_width;

  if (GTK_VIEWPORT (widget)->shadow_type != GTK_SHADOW_NONE)

    {

      requisition->width += 2 * widget->style->xthickness;

      requisition->height += 2 * widget->style->ythickness;

    }

  if (bin->child && gtk_widget_get_visible (bin->child))

    {

      gtk_widget_size_request (bin->child, &child_requisition);

      requisition->width += child_requisition.width;

      requisition->height += child_requisition.height;

    }

}

static void

gtk_viewport_size_allocate (GtkWidget     *widget,

			    GtkAllocation *allocation)

{

  GtkViewport *viewport = GTK_VIEWPORT (widget);

  GtkBin *bin = GTK_BIN (widget);

  gint border_width = GTK_CONTAINER (widget)->border_width;

  gboolean hadjustment_value_changed, vadjustment_value_changed;

  GtkAdjustment *hadjustment = gtk_viewport_get_hadjustment (viewport);

  GtkAdjustment *vadjustment = gtk_viewport_get_vadjustment (viewport);

  GtkAllocation child_allocation;

  /* If our size changed, and we have a shadow, queue a redraw on widget->window to

   * redraw the shadow correctly.

   */

  if (gtk_widget_get_mapped (widget) &&

      viewport->shadow_type != GTK_SHADOW_NONE &&

      (widget->allocation.width != allocation->width ||

       widget->allocation.height != allocation->height))

    gdk_window_invalidate_rect (widget->window, NULL, FALSE);

  widget->allocation = *allocation;

  viewport_set_hadjustment_values (viewport, &hadjustment_value_changed);

  viewport_set_vadjustment_values (viewport, &vadjustment_value_changed);

  child_allocation.x = 0;

  child_allocation.y = 0;

  child_allocation.width = hadjustment->upper;

  child_allocation.height = vadjustment->upper;

  if (gtk_widget_get_realized (widget))

    {

      GtkAllocation view_allocation;

      gdk_window_move_resize (widget->window,

			      allocation->x + border_width,

			      allocation->y + border_width,

			      allocation->width - border_width * 2,

			      allocation->height - border_width * 2);

      viewport_get_view_allocation (viewport, &view_allocation);

      gdk_window_move_resize (viewport->view_window,

			      view_allocation.x,

			      view_allocation.y,

			      view_allocation.width,

			      view_allocation.height);

      gdk_window_move_resize (viewport->bin_window,

                              - hadjustment->value,

                              - vadjustment->value,

                              child_allocation.width,

                              child_allocation.height);

    }

  if (bin->child && gtk_widget_get_visible (bin->child))

    gtk_widget_size_allocate (bin->child, &child_allocation);

  gtk_adjustment_changed (hadjustment);

  gtk_adjustment_changed (vadjustment);

  if (hadjustment_value_changed)

    gtk_adjustment_value_changed (hadjustment);

  if (vadjustment_value_changed)

    gtk_adjustment_value_changed (vadjustment);

}

static void

gtk_viewport_adjustment_value_changed (GtkAdjustment *adjustment,

				       gpointer       data)

{

  GtkViewport *viewport = GTK_VIEWPORT (data);

  GtkBin *bin = GTK_BIN (data);

  if (bin->child && gtk_widget_get_visible (bin->child) &&

      gtk_widget_get_realized (GTK_WIDGET (viewport)))

    {

      GtkAdjustment *hadjustment = gtk_viewport_get_hadjustment (viewport);

      GtkAdjustment *vadjustment = gtk_viewport_get_vadjustment (viewport);

      gint old_x, old_y;

      gint new_x, new_y;

      gdk_window_get_position (viewport->bin_window, &old_x, &old_y);

      new_x = - hadjustment->value;

      new_y = - vadjustment->value;

      if (new_x != old_x || new_y != old_y)

	{

	  gdk_window_move (viewport->bin_window, new_x, new_y);

	  gdk_window_process_updates (viewport->bin_window, TRUE);

	}

    }

}

static void

gtk_viewport_style_set (GtkWidget *widget,

			GtkStyle  *previous_style)

{

   if (gtk_widget_get_realized (widget) &&

       gtk_widget_get_has_window (widget))