Add a vfunc to return a non-scrollable border around scrollables. This would be nicer as a property, but we can't add properties to an interface without breaking 3rd party implementations, so make this an optional vfunc, and handle it not being set.
		
			
				
	
	
		
			343 lines
		
	
	
		
			9.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			343 lines
		
	
	
		
			9.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* gtkscrollable.c
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 * Copyright (C) 2008 Tadej Borovšak <tadeboro@gmail.com>
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 *
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 * This library is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2 of the License, or (at your option) any later version.
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 *
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 * This library is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
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 */
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/**
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 * SECTION:gtkscrollable
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 * @Short_Description: An interface for scrollable widgets
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 * @Title: GtkScrollable
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 *
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 * #GtkScrollable is an interface that is implemented by widgets with native
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 * scrolling ability.
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 *
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 * To implement this interface you should override the
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 * #GtkScrollable:hadjustment and #GtkScrollable:vadjustment properties.
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 *
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 * ## Creating a scrollable widget
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 *
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 * All scrollable widgets should do the following.
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 *
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 * - When a parent widget sets the scrollable child widget’s adjustments,
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 *   the widget should populate the adjustments’
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 *   #GtkAdjustment:lower, #GtkAdjustment:upper,
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 *   #GtkAdjustment:step-increment, #GtkAdjustment:page-increment and
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 *   #GtkAdjustment:page-size properties and connect to the
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 *   #GtkAdjustment::value-changed signal.
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 *
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 * - Because its preferred size is the size for a fully expanded widget,
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 *   the scrollable widget must be able to cope with underallocations.
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 *   This means that it must accept any value passed to its
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 *   #GtkWidgetClass.size_allocate() function.
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 *
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 * - When the parent allocates space to the scrollable child widget,
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 *   the widget should update the adjustments’ properties with new values.
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 *
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 * - When any of the adjustments emits the #GtkAdjustment::value-changed signal,
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 *   the scrollable widget should scroll its contents.
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 */
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#include "config.h"
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#include "gtkscrollable.h"
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#include "gtkadjustment.h"
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#include "gtkprivate.h"
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#include "gtktypebuiltins.h"
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#include "gtkintl.h"
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G_DEFINE_INTERFACE (GtkScrollable, gtk_scrollable, G_TYPE_OBJECT)
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static void
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gtk_scrollable_default_init (GtkScrollableInterface *iface)
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{
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  GParamSpec *pspec;
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  /**
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   * GtkScrollable:hadjustment:
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   *
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   * Horizontal #GtkAdjustment of the scrollable widget. This adjustment is
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   * shared between the scrollable widget and its parent.
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   *
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   * Since: 3.0
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   */
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  pspec = g_param_spec_object ("hadjustment",
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                               P_("Horizontal adjustment"),
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                               P_("Horizontal adjustment that is shared "
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                                  "between the scrollable widget and its "
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                                  "controller"),
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                               GTK_TYPE_ADJUSTMENT,
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                               GTK_PARAM_READWRITE | G_PARAM_CONSTRUCT);
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  g_object_interface_install_property (iface, pspec);
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  /**
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   * GtkScrollable:vadjustment:
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   *
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   * Verical #GtkAdjustment of the scrollable widget. This adjustment is shared
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   * between the scrollable widget and its parent.
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   *
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   * Since: 3.0
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   */
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  pspec = g_param_spec_object ("vadjustment",
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                               P_("Vertical adjustment"),
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                               P_("Vertical adjustment that is shared "
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                                  "between the scrollable widget and its "
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                                  "controller"),
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                               GTK_TYPE_ADJUSTMENT,
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                               GTK_PARAM_READWRITE | G_PARAM_CONSTRUCT);
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  g_object_interface_install_property (iface, pspec);
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  /**
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   * GtkScrollable:hscroll-policy:
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   *
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   * Determines whether horizontal scrolling should start once the scrollable
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   * widget is allocated less than its minimum width or less than its natural width.
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   *
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   * Since: 3.0
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   */
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  pspec = g_param_spec_enum ("hscroll-policy",
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			     P_("Horizontal Scrollable Policy"),
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			     P_("How the size of the content should be determined"),
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			     GTK_TYPE_SCROLLABLE_POLICY,
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			     GTK_SCROLL_MINIMUM,
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			     GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY);
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  g_object_interface_install_property (iface, pspec);
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  /**
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   * GtkScrollable:vscroll-policy:
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   *
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   * Determines whether vertical scrolling should start once the scrollable
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   * widget is allocated less than its minimum height or less than its natural height.
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   *
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   * Since: 3.0
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   */
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  pspec = g_param_spec_enum ("vscroll-policy",
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			     P_("Vertical Scrollable Policy"),
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			     P_("How the size of the content should be determined"),
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			     GTK_TYPE_SCROLLABLE_POLICY,
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			     GTK_SCROLL_MINIMUM,
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			     GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY);
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  g_object_interface_install_property (iface, pspec);
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}
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/**
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 * gtk_scrollable_get_hadjustment:
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 * @scrollable: a #GtkScrollable
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 *
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 * Retrieves the #GtkAdjustment used for horizontal scrolling.
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 *
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 * Returns: (transfer none): horizontal #GtkAdjustment.
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 *
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 * Since: 3.0
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 **/
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GtkAdjustment *
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gtk_scrollable_get_hadjustment (GtkScrollable *scrollable)
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{
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  GtkAdjustment *adj = NULL;
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  g_return_val_if_fail (GTK_IS_SCROLLABLE (scrollable), NULL);
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  g_object_get (scrollable, "hadjustment", &adj, NULL);
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  /* Horrid hack; g_object_get() returns a new reference but
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   * that contradicts the memory management conventions
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   * for accessors.
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   */
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  if (adj)
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    g_object_unref (adj);
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  return adj;
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}
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/**
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 * gtk_scrollable_set_hadjustment:
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 * @scrollable: a #GtkScrollable
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 * @hadjustment: (allow-none): a #GtkAdjustment
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 *
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 * Sets the horizontal adjustment of the #GtkScrollable.
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 *
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 * Since: 3.0
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 **/
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void
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gtk_scrollable_set_hadjustment (GtkScrollable *scrollable,
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                                GtkAdjustment *hadjustment)
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{
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  g_return_if_fail (GTK_IS_SCROLLABLE (scrollable));
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  g_return_if_fail (hadjustment == NULL || GTK_IS_ADJUSTMENT (hadjustment));
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  g_object_set (scrollable, "hadjustment", hadjustment, NULL);
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}
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/**
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 * gtk_scrollable_get_vadjustment:
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 * @scrollable: a #GtkScrollable
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 *
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 * Retrieves the #GtkAdjustment used for vertical scrolling.
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 *
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 * Returns: (transfer none): vertical #GtkAdjustment.
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 *
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 * Since: 3.0
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 **/
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GtkAdjustment *
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gtk_scrollable_get_vadjustment (GtkScrollable *scrollable)
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{
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  GtkAdjustment *adj = NULL;
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  g_return_val_if_fail (GTK_IS_SCROLLABLE (scrollable), NULL);
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  g_object_get (scrollable, "vadjustment", &adj, NULL);
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  /* Horrid hack; g_object_get() returns a new reference but
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   * that contradicts the memory management conventions
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   * for accessors.
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   */
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  if (adj)
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    g_object_unref (adj);
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  return adj;
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}
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/**
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 * gtk_scrollable_set_vadjustment:
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 * @scrollable: a #GtkScrollable
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 * @vadjustment: (allow-none): a #GtkAdjustment
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 *
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 * Sets the vertical adjustment of the #GtkScrollable.
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 *
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 * Since: 3.0
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 **/
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void
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gtk_scrollable_set_vadjustment (GtkScrollable *scrollable,
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                                GtkAdjustment *vadjustment)
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{
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  g_return_if_fail (GTK_IS_SCROLLABLE (scrollable));
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  g_return_if_fail (vadjustment == NULL || GTK_IS_ADJUSTMENT (vadjustment));
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  g_object_set (scrollable, "vadjustment", vadjustment, NULL);
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}
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/**
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 * gtk_scrollable_get_hscroll_policy:
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 * @scrollable: a #GtkScrollable
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 *
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 * Gets the horizontal #GtkScrollablePolicy.
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 *
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 * Returns: The horizontal #GtkScrollablePolicy.
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 *
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 * Since: 3.0
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 **/
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GtkScrollablePolicy
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gtk_scrollable_get_hscroll_policy (GtkScrollable *scrollable)
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{
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  GtkScrollablePolicy policy;
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  g_return_val_if_fail (GTK_IS_SCROLLABLE (scrollable), GTK_SCROLL_MINIMUM);
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  g_object_get (scrollable, "hscroll-policy", &policy, NULL);
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  return policy;
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}
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/**
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 * gtk_scrollable_set_hscroll_policy:
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 * @scrollable: a #GtkScrollable
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 * @policy: the horizontal #GtkScrollablePolicy
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 *
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 * Sets the #GtkScrollablePolicy to determine whether
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 * horizontal scrolling should start below the minimum width or
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 * below the natural width.
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 *
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 * Since: 3.0
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 **/
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void
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gtk_scrollable_set_hscroll_policy (GtkScrollable       *scrollable,
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				   GtkScrollablePolicy  policy)
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{
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  g_return_if_fail (GTK_IS_SCROLLABLE (scrollable));
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  g_object_set (scrollable, "hscroll-policy", policy, NULL);
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}
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/**
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 * gtk_scrollable_get_vscroll_policy:
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 * @scrollable: a #GtkScrollable
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 *
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 * Gets the vertical #GtkScrollablePolicy.
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 *
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 * Returns: The vertical #GtkScrollablePolicy.
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 *
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 * Since: 3.0
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 **/
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GtkScrollablePolicy
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gtk_scrollable_get_vscroll_policy (GtkScrollable *scrollable)
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{
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  GtkScrollablePolicy policy;
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  g_return_val_if_fail (GTK_IS_SCROLLABLE (scrollable), GTK_SCROLL_MINIMUM);
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  g_object_get (scrollable, "vscroll-policy", &policy, NULL);
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  return policy;
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}
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/**
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 * gtk_scrollable_set_vscroll_policy:
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 * @scrollable: a #GtkScrollable
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 * @policy: the vertical #GtkScrollablePolicy
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 *
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 * Sets the #GtkScrollablePolicy to determine whether
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 * vertical scrolling should start below the minimum height or
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 * below the natural height.
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 *
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 * Since: 3.0
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 **/
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void
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gtk_scrollable_set_vscroll_policy (GtkScrollable       *scrollable,
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				   GtkScrollablePolicy  policy)
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{
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  g_return_if_fail (GTK_IS_SCROLLABLE (scrollable));
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  g_object_set (scrollable, "vscroll-policy", policy, NULL);
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}
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/**
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 * gtk_scrollable_get_border:
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 * @scrollable: a #GtkScrollable
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 * @border: return location for the results
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 *
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 * Returns the size of a non-scrolling border around the
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 * outside of the scrollable. An example for this would
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 * be treeview headers. GTK+ can use this information to
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 * display overlayed graphics, like the overshoot indication,
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 * at the right position.
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 *
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 * Returns: %TRUE if @border has been set
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 *
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 * Since: 3.16
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 */
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gboolean
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gtk_scrollable_get_border (GtkScrollable *scrollable,
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                           GtkBorder     *border)
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{
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  g_return_val_if_fail (GTK_IS_SCROLLABLE (scrollable), FALSE);
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  g_return_val_if_fail (border != NULL, FALSE);
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  if (GTK_SCROLLABLE_GET_IFACE (scrollable)->get_border)
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    return GTK_SCROLLABLE_GET_IFACE (scrollable)->get_border (scrollable, border);
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  return FALSE;
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}
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