gtk2/gtk/gtkviewport.c
2016-12-20 18:01:10 +01:00

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/* 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, see <http://www.gnu.org/licenses/>.
*/
/*
* 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 "gtkadjustment.h"
#include "gtkcsscustomgadgetprivate.h"
#include "gtkintl.h"
#include "gtkmarshalers.h"
#include "gtkprivate.h"
#include "gtkrenderbackgroundprivate.h"
#include "gtkscrollable.h"
#include "gtksnapshot.h"
#include "gtkstylecontextprivate.h"
#include "gtktypebuiltins.h"
#include "gtkwidgetprivate.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
* #GtkGrid, #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.
* gtk_container_add() does this automatically if a child that does not
* implement #GtkScrollable is added to a #GtkScrolledWindow, so you can
* ignore the presence of the viewport.
*
* The GtkViewport will start scrolling content only if allocated less
* than the child widgets minimum size in a given orientation.
*
* # CSS nodes
*
* GtkViewport has a single CSS node with name viewport.
*/
struct _GtkViewportPrivate
{
GtkAdjustment *hadjustment;
GtkAdjustment *vadjustment;
GtkShadowType shadow_type;
GdkWindow *bin_window;
GdkWindow *view_window;
GtkCssGadget *gadget;
/* GtkScrollablePolicy needs to be checked when
* driving the scrollable adjustment values */
guint hscroll_policy : 1;
guint vscroll_policy : 1;
};
enum {
PROP_0,
PROP_HADJUSTMENT,
PROP_VADJUSTMENT,
PROP_HSCROLL_POLICY,
PROP_VSCROLL_POLICY,
PROP_SHADOW_TYPE
};
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_finalize (GObject *object);
static void gtk_viewport_destroy (GtkWidget *widget);
static void gtk_viewport_realize (GtkWidget *widget);
static void gtk_viewport_unrealize (GtkWidget *widget);
static void gtk_viewport_snapshot (GtkWidget *widget,
GtkSnapshot *snapshot);
static void gtk_viewport_add (GtkContainer *container,
GtkWidget *widget);
static void gtk_viewport_size_allocate (GtkWidget *widget,
GtkAllocation *allocation);
static void gtk_viewport_adjustment_value_changed (GtkAdjustment *adjustment,
gpointer data);
static void viewport_set_adjustment (GtkViewport *viewport,
GtkOrientation orientation,
GtkAdjustment *adjustment);
G_DEFINE_TYPE_WITH_CODE (GtkViewport, gtk_viewport, GTK_TYPE_BIN,
G_ADD_PRIVATE (GtkViewport)
G_IMPLEMENT_INTERFACE (GTK_TYPE_SCROLLABLE, NULL))
static void
gtk_viewport_measure (GtkCssGadget *gadget,
GtkOrientation orientation,
int for_size,
int *minimum,
int *natural,
int *minimum_baseline,
int *natural_baseline,
gpointer data)
{
GtkWidget *widget = gtk_css_gadget_get_owner (gadget);
GtkWidget *child;
*minimum = *natural = 0;
child = gtk_bin_get_child (GTK_BIN (widget));
if (child && gtk_widget_get_visible (child))
gtk_widget_measure (child,
orientation,
for_size,
minimum, natural,
NULL, NULL);
}
static void
viewport_set_adjustment_values (GtkViewport *viewport,
GtkOrientation orientation)
{
GtkBin *bin = GTK_BIN (viewport);
GtkViewportPrivate *priv = gtk_viewport_get_instance_private (viewport);
GtkAdjustment *adjustment;
GtkScrollablePolicy scroll_policy;
GtkScrollablePolicy other_scroll_policy;
GtkOrientation other_orientation;
GtkAllocation view_allocation;
GtkWidget *child;
gdouble upper, value;
int viewport_size, other_viewport_size;
gtk_css_gadget_get_content_allocation (viewport->priv->gadget,
&view_allocation, NULL);
if (orientation == GTK_ORIENTATION_HORIZONTAL)
{
adjustment = priv->hadjustment;
other_orientation = GTK_ORIENTATION_VERTICAL;
viewport_size = view_allocation.width;
other_viewport_size = view_allocation.height;
scroll_policy = priv->hscroll_policy;
other_scroll_policy = priv->vscroll_policy;
}
else /* VERTICAL */
{
adjustment = priv->vadjustment;
other_orientation = GTK_ORIENTATION_HORIZONTAL;
viewport_size = view_allocation.height;
other_viewport_size = view_allocation.width;
scroll_policy = priv->vscroll_policy;
other_scroll_policy = priv->hscroll_policy;
}
child = gtk_bin_get_child (bin);
if (child && gtk_widget_get_visible (child))
{
int min_size, nat_size;
int scroll_size;
if (other_scroll_policy == GTK_SCROLL_MINIMUM)
gtk_widget_measure (child, other_orientation, -1,
&scroll_size, NULL, NULL, NULL);
else
gtk_widget_measure (child, other_orientation, -1,
NULL, &scroll_size, NULL, NULL);
gtk_widget_measure (child, orientation,
MAX (other_viewport_size, scroll_size),
&min_size, &nat_size, NULL, NULL);
if (scroll_policy == GTK_SCROLL_MINIMUM)
upper = MAX (min_size, viewport_size);
else
upper = MAX (nat_size, viewport_size);
}
else
{
upper = viewport_size;
}
value = gtk_adjustment_get_value (adjustment);
/* We clamp to the left in RTL mode */
if (orientation == GTK_ORIENTATION_HORIZONTAL &&
gtk_widget_get_direction (GTK_WIDGET (viewport)) == GTK_TEXT_DIR_RTL)
{
gdouble dist = gtk_adjustment_get_upper (adjustment)
- value
- gtk_adjustment_get_page_size (adjustment);
value = upper - dist - viewport_size;
}
gtk_adjustment_configure (adjustment,
value,
0,
upper,
viewport_size * 0.1,
viewport_size * 0.9,
viewport_size);
}
static void
gtk_viewport_allocate (GtkCssGadget *gadget,
const GtkAllocation *allocation,
int baseline,
GtkAllocation *out_clip,
gpointer data)
{
GtkWidget *widget = gtk_css_gadget_get_owner (gadget);
GtkViewport *viewport = GTK_VIEWPORT (widget);
GtkViewportPrivate *priv = viewport->priv;
GtkAdjustment *hadjustment = priv->hadjustment;
GtkAdjustment *vadjustment = priv->vadjustment;
GtkWidget *child;
g_object_freeze_notify (G_OBJECT (hadjustment));
g_object_freeze_notify (G_OBJECT (vadjustment));
viewport_set_adjustment_values (viewport, GTK_ORIENTATION_HORIZONTAL);
viewport_set_adjustment_values (viewport, GTK_ORIENTATION_VERTICAL);
if (gtk_widget_get_realized (widget))
{
gdk_window_move_resize (priv->view_window,
allocation->x,
allocation->y,
allocation->width,
allocation->height);
gdk_window_move_resize (priv->bin_window,
- gtk_adjustment_get_value (hadjustment),
- gtk_adjustment_get_value (vadjustment),
gtk_adjustment_get_upper (hadjustment),
gtk_adjustment_get_upper (vadjustment));
}
child = gtk_bin_get_child (GTK_BIN (widget));
if (child && gtk_widget_get_visible (child))
{
GtkAllocation child_allocation;
child_allocation.x = 0;
child_allocation.y = 0;
child_allocation.width = gtk_adjustment_get_upper (hadjustment);
child_allocation.height = gtk_adjustment_get_upper (vadjustment);
gtk_widget_size_allocate (child, &child_allocation);
}
g_object_thaw_notify (G_OBJECT (hadjustment));
g_object_thaw_notify (G_OBJECT (vadjustment));
}
static gboolean
gtk_viewport_render (GtkCssGadget *gadget,
GtkSnapshot *snapshot,
int x,
int y,
int width,
int height,
gpointer data)
{
GtkWidget *widget = gtk_css_gadget_get_owner (gadget);
gtk_snapshot_push_clip (snapshot, &GRAPHENE_RECT_INIT(x, y, width, height), "Viewport");
GTK_WIDGET_CLASS (gtk_viewport_parent_class)->snapshot (widget, snapshot);
gtk_snapshot_pop_and_append (snapshot);
return FALSE;
}
static void
gtk_viewport_measure_ (GtkWidget *widget,
GtkOrientation orientation,
int for_size,
int *minimum,
int *natural,
int *minimum_baseline,
int *natural_baseline)
{
gtk_css_gadget_get_preferred_size (GTK_VIEWPORT (widget)->priv->gadget,
orientation,
for_size,
minimum, natural,
minimum_baseline, natural_baseline);
}
static void
gtk_viewport_class_init (GtkViewportClass *class)
{
GObjectClass *gobject_class;
GtkWidgetClass *widget_class;
GtkContainerClass *container_class;
gobject_class = G_OBJECT_CLASS (class);
widget_class = (GtkWidgetClass*) class;
container_class = (GtkContainerClass*) class;
gobject_class->set_property = gtk_viewport_set_property;
gobject_class->get_property = gtk_viewport_get_property;
gobject_class->finalize = gtk_viewport_finalize;
widget_class->destroy = gtk_viewport_destroy;
widget_class->realize = gtk_viewport_realize;
widget_class->unrealize = gtk_viewport_unrealize;
widget_class->snapshot = gtk_viewport_snapshot;
widget_class->size_allocate = gtk_viewport_size_allocate;
widget_class->measure = gtk_viewport_measure_;
gtk_widget_class_set_accessible_role (widget_class, ATK_ROLE_VIEWPORT);
container_class->add = gtk_viewport_add;
/* GtkScrollable implementation */
g_object_class_override_property (gobject_class, PROP_HADJUSTMENT, "hadjustment");
g_object_class_override_property (gobject_class, PROP_VADJUSTMENT, "vadjustment");
g_object_class_override_property (gobject_class, PROP_HSCROLL_POLICY, "hscroll-policy");
g_object_class_override_property (gobject_class, PROP_VSCROLL_POLICY, "vscroll-policy");
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|G_PARAM_EXPLICIT_NOTIFY));
gtk_widget_class_set_css_name (widget_class, "viewport");
}
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:
viewport_set_adjustment (viewport, GTK_ORIENTATION_HORIZONTAL, g_value_get_object (value));
break;
case PROP_VADJUSTMENT:
viewport_set_adjustment (viewport, GTK_ORIENTATION_VERTICAL, g_value_get_object (value));
break;
case PROP_HSCROLL_POLICY:
if (viewport->priv->hscroll_policy != g_value_get_enum (value))
{
viewport->priv->hscroll_policy = g_value_get_enum (value);
gtk_widget_queue_resize (GTK_WIDGET (viewport));
g_object_notify_by_pspec (object, pspec);
}
break;
case PROP_VSCROLL_POLICY:
if (viewport->priv->vscroll_policy != g_value_get_enum (value))
{
viewport->priv->vscroll_policy = g_value_get_enum (value);
gtk_widget_queue_resize (GTK_WIDGET (viewport));
g_object_notify_by_pspec (object, pspec);
}
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 = GTK_VIEWPORT (object);
GtkViewportPrivate *priv = viewport->priv;
switch (prop_id)
{
case PROP_HADJUSTMENT:
g_value_set_object (value, priv->hadjustment);
break;
case PROP_VADJUSTMENT:
g_value_set_object (value, priv->vadjustment);
break;
case PROP_HSCROLL_POLICY:
g_value_set_enum (value, priv->hscroll_policy);
break;
case PROP_VSCROLL_POLICY:
g_value_set_enum (value, priv->vscroll_policy);
break;
case PROP_SHADOW_TYPE:
g_value_set_enum (value, priv->shadow_type);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gtk_viewport_init (GtkViewport *viewport)
{
GtkWidget *widget;
GtkViewportPrivate *priv;
GtkCssNode *widget_node;
viewport->priv = gtk_viewport_get_instance_private (viewport);
priv = viewport->priv;
widget = GTK_WIDGET (viewport);
gtk_widget_set_has_window (widget, FALSE);
gtk_widget_set_redraw_on_allocate (widget, FALSE);
priv->shadow_type = GTK_SHADOW_IN;
priv->view_window = NULL;
priv->bin_window = NULL;
priv->hadjustment = NULL;
priv->vadjustment = NULL;
widget_node = gtk_widget_get_css_node (widget);
priv->gadget = gtk_css_custom_gadget_new_for_node (widget_node,
widget,
gtk_viewport_measure,
gtk_viewport_allocate,
NULL,
gtk_viewport_render,
NULL, NULL);
gtk_css_gadget_add_class (priv->gadget, GTK_STYLE_CLASS_FRAME);
viewport_set_adjustment (viewport, GTK_ORIENTATION_HORIZONTAL, NULL);
viewport_set_adjustment (viewport, GTK_ORIENTATION_VERTICAL, NULL);
}
/**
* gtk_viewport_new:
* @hadjustment: (allow-none): horizontal adjustment
* @vadjustment: (allow-none): vertical adjustment
*
* Creates a new #GtkViewport with the given adjustments, or with default
* adjustments if none are given.
*
* Returns: a new #GtkViewport
*/
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)->priv->hadjustment : &(viewport)->priv->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_destroy (GtkWidget *widget)
{
GtkViewport *viewport = GTK_VIEWPORT (widget);
viewport_disconnect_adjustment (viewport, GTK_ORIENTATION_HORIZONTAL);
viewport_disconnect_adjustment (viewport, GTK_ORIENTATION_VERTICAL);
GTK_WIDGET_CLASS (gtk_viewport_parent_class)->destroy (widget);
}
static void
gtk_viewport_finalize (GObject *object)
{
GtkViewport *viewport = GTK_VIEWPORT (object);
GtkViewportPrivate *priv = viewport->priv;
g_clear_object (&priv->gadget);
G_OBJECT_CLASS (gtk_viewport_parent_class)->finalize (object);
}
static void
viewport_set_adjustment (GtkViewport *viewport,
GtkOrientation orientation,
GtkAdjustment *adjustment)
{
GtkAdjustment **adjustmentp = ADJUSTMENT_POINTER (viewport, orientation);
if (adjustment && adjustment == *adjustmentp)
return;
if (!adjustment)
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);
viewport_set_adjustment_values (viewport, orientation);
g_signal_connect (adjustment, "value-changed",
G_CALLBACK (gtk_viewport_adjustment_value_changed),
viewport);
gtk_viewport_adjustment_value_changed (adjustment, viewport);
}
/**
* 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)
{
GtkViewportPrivate *priv;
GtkWidget *widget;
GtkStyleContext *context;
g_return_if_fail (GTK_IS_VIEWPORT (viewport));
widget = GTK_WIDGET (viewport);
priv = viewport->priv;
if ((GtkShadowType) priv->shadow_type != type)
{
priv->shadow_type = type;
context = gtk_widget_get_style_context (widget);
if (type != GTK_SHADOW_NONE)
gtk_style_context_add_class (context, GTK_STYLE_CLASS_FRAME);
else
gtk_style_context_remove_class (context, GTK_STYLE_CLASS_FRAME);
gtk_widget_queue_resize (widget);
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().
*
* Returns: 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->priv->shadow_type;
}
/**
* gtk_viewport_get_bin_window:
* @viewport: a #GtkViewport
*
* Gets the bin window of the #GtkViewport.
*
* Returns: (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->priv->bin_window;
}
/**
* gtk_viewport_get_view_window:
* @viewport: a #GtkViewport
*
* Gets the view window of the #GtkViewport.
*
* Returns: (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->priv->view_window;
}
static void
gtk_viewport_realize (GtkWidget *widget)
{
GtkViewport *viewport = GTK_VIEWPORT (widget);
GtkViewportPrivate *priv = viewport->priv;
GtkBin *bin = GTK_BIN (widget);
GtkAdjustment *hadjustment = priv->hadjustment;
GtkAdjustment *vadjustment = priv->vadjustment;
GtkAllocation view_allocation;
GtkWidget *child;
gint event_mask;
GTK_WIDGET_CLASS (gtk_viewport_parent_class)->realize (widget);
event_mask = gtk_widget_get_events (widget);
gtk_css_gadget_get_content_allocation (priv->gadget,
&view_allocation, NULL);
priv->view_window = gdk_window_new_child (gtk_widget_get_window (widget),
event_mask | GDK_SCROLL_MASK | GDK_TOUCH_MASK | GDK_SMOOTH_SCROLL_MASK,
&view_allocation);
gtk_widget_register_window (widget, priv->view_window);
priv->bin_window = gdk_window_new_child (priv->view_window,
event_mask,
&(GdkRectangle) {
- gtk_adjustment_get_value (hadjustment),
- gtk_adjustment_get_value (vadjustment),
gtk_adjustment_get_upper (hadjustment),
gtk_adjustment_get_upper (vadjustment)});
gtk_widget_register_window (widget, priv->bin_window);
child = gtk_bin_get_child (bin);
if (child)
gtk_widget_set_parent_window (child, priv->bin_window);
gdk_window_show (priv->bin_window);
gdk_window_show (priv->view_window);
}
static void
gtk_viewport_unrealize (GtkWidget *widget)
{
GtkViewport *viewport = GTK_VIEWPORT (widget);
GtkViewportPrivate *priv = viewport->priv;
gtk_widget_unregister_window (widget, priv->view_window);
gdk_window_destroy (priv->view_window);
priv->view_window = NULL;
gtk_widget_unregister_window (widget, priv->bin_window);
gdk_window_destroy (priv->bin_window);
priv->bin_window = NULL;
GTK_WIDGET_CLASS (gtk_viewport_parent_class)->unrealize (widget);
}
static void
gtk_viewport_snapshot (GtkWidget *widget,
GtkSnapshot *snapshot)
{
GtkViewport *viewport = GTK_VIEWPORT (widget);
GtkViewportPrivate *priv = viewport->priv;
gtk_css_gadget_snapshot (priv->gadget, snapshot);
}
static void
gtk_viewport_add (GtkContainer *container,
GtkWidget *child)
{
GtkBin *bin = GTK_BIN (container);
GtkViewport *viewport = GTK_VIEWPORT (bin);
GtkViewportPrivate *priv = viewport->priv;
g_return_if_fail (gtk_bin_get_child (bin) == NULL);
gtk_widget_set_parent_window (child, priv->bin_window);
GTK_CONTAINER_CLASS (gtk_viewport_parent_class)->add (container, child);
}
static void
gtk_viewport_size_allocate (GtkWidget *widget,
GtkAllocation *allocation)
{
GtkViewport *viewport = GTK_VIEWPORT (widget);
GtkViewportPrivate *priv = viewport->priv;
GtkAllocation clip, content_allocation, widget_allocation;
/* If our size changed, and we have a shadow, queue a redraw on widget->window to
* redraw the shadow correctly.
*/
gtk_widget_get_allocation (widget, &widget_allocation);
if (gtk_widget_get_mapped (widget) &&
priv->shadow_type != GTK_SHADOW_NONE &&
(widget_allocation.width != allocation->width ||
widget_allocation.height != allocation->height))
gdk_window_invalidate_rect (gtk_widget_get_window (widget), NULL, FALSE);
gtk_widget_set_allocation (widget, allocation);
content_allocation = *allocation;
gtk_css_gadget_allocate (priv->gadget,
&content_allocation,
gtk_widget_get_allocated_baseline (widget),
&clip);
gtk_widget_set_clip (widget, &clip);
}
static void
gtk_viewport_adjustment_value_changed (GtkAdjustment *adjustment,
gpointer data)
{
GtkViewport *viewport = GTK_VIEWPORT (data);
GtkViewportPrivate *priv = viewport->priv;
GtkBin *bin = GTK_BIN (data);
GtkWidget *child;
child = gtk_bin_get_child (bin);
if (child && gtk_widget_get_visible (child) &&
gtk_widget_get_realized (GTK_WIDGET (viewport)))
{
GtkAdjustment *hadjustment = priv->hadjustment;
GtkAdjustment *vadjustment = priv->vadjustment;
gint old_x, old_y;
gint new_x, new_y;
gdk_window_get_position (priv->bin_window, &old_x, &old_y);
new_x = - gtk_adjustment_get_value (hadjustment);
new_y = - gtk_adjustment_get_value (vadjustment);
if (new_x != old_x || new_y != old_y)
gdk_window_move (priv->bin_window, new_x, new_y);
}
}