gtk2/gtk/gtkscrollable.c
2014-02-07 13:26:12 -05:00

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/* gtkscrollable.c
* Copyright (C) 2008 Tadej Borovšak <tadeboro@gmail.com>
*
* 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/>.
*/
/**
* SECTION:gtkscrollable
* @Short_Description: An interface for scrollable widgets
* @Title: GtkScrollable
*
* #GtkScrollable is an interface that is implemented by widgets with native
* scrolling ability.
*
* To implement this interface you should override the
* #GtkScrollable:hadjustment and #GtkScrollable:vadjustment properties.
*
* ## Creating a scrollable widget
*
* All scrollable widgets should do the following.
*
* - When a parent widget sets the scrollable child widgets adjustments,
* the widget should populate the adjustments
* #GtkAdjustment:lower, #GtkAdjustment:upper,
* #GtkAdjustment:step-increment, #GtkAdjustment:page-increment and
* #GtkAdjustment:page-size properties and connect to the
* #GtkAdjustment::value-changed signal.
*
* - Because its preferred size is the size for a fully expanded widget,
* the scrollable widget must be able to cope with underallocations.
* This means that it must accept any value passed to its
* #GtkWidgetClass.size_allocate() function.
*
* - When the parent allocates space to the scrollable child widget,
* the widget should update the adjustments properties with new values.
*
* - When any of the adjustments emits the #GtkAdjustment::value-changed signal,
* the scrollable widget should scroll its contents.
*/
#include "config.h"
#include "gtkscrollable.h"
#include "gtkadjustment.h"
#include "gtkprivate.h"
#include "gtktypebuiltins.h"
#include "gtkintl.h"
G_DEFINE_INTERFACE (GtkScrollable, gtk_scrollable, G_TYPE_OBJECT)
static void
gtk_scrollable_default_init (GtkScrollableInterface *iface)
{
GParamSpec *pspec;
/**
* GtkScrollable:hadjustment:
*
* Horizontal #GtkAdjustment of the scrollable widget. This adjustment is
* shared between the scrollable widget and its parent.
*
* Since: 3.0
*/
pspec = g_param_spec_object ("hadjustment",
P_("Horizontal adjustment"),
P_("Horizontal adjustment that is shared "
"between the scrollable widget and its "
"controller"),
GTK_TYPE_ADJUSTMENT,
GTK_PARAM_READWRITE | G_PARAM_CONSTRUCT);
g_object_interface_install_property (iface, pspec);
/**
* GtkScrollable:vadjustment:
*
* Verical #GtkAdjustment of the scrollable widget. This adjustment is shared
* between the scrollable widget and its parent.
*
* Since: 3.0
*/
pspec = g_param_spec_object ("vadjustment",
P_("Vertical adjustment"),
P_("Vertical adjustment that is shared "
"between the scrollable widget and its "
"controller"),
GTK_TYPE_ADJUSTMENT,
GTK_PARAM_READWRITE | G_PARAM_CONSTRUCT);
g_object_interface_install_property (iface, pspec);
/**
* GtkScrollable:hscroll-policy:
*
* Determines whether horizontal scrolling should start once the scrollable
* widget is allocated less than its minimum width or less than its natural width.
*
* Since: 3.0
*/
pspec = g_param_spec_enum ("hscroll-policy",
P_("Horizontal Scrollable Policy"),
P_("How the size of the content should be determined"),
GTK_TYPE_SCROLLABLE_POLICY,
GTK_SCROLL_MINIMUM,
GTK_PARAM_READWRITE);
g_object_interface_install_property (iface, pspec);
/**
* GtkScrollable:vscroll-policy:
*
* Determines whether vertical scrolling should start once the scrollable
* widget is allocated less than its minimum height or less than its natural height.
*
* Since: 3.0
*/
pspec = g_param_spec_enum ("vscroll-policy",
P_("Vertical Scrollable Policy"),
P_("How the size of the content should be determined"),
GTK_TYPE_SCROLLABLE_POLICY,
GTK_SCROLL_MINIMUM,
GTK_PARAM_READWRITE);
g_object_interface_install_property (iface, pspec);
}
/**
* gtk_scrollable_get_hadjustment:
* @scrollable: a #GtkScrollable
*
* Retrieves the #GtkAdjustment used for horizontal scrolling.
*
* Return value: (transfer none): horizontal #GtkAdjustment.
*
* Since: 3.0
**/
GtkAdjustment *
gtk_scrollable_get_hadjustment (GtkScrollable *scrollable)
{
GtkAdjustment *adj = NULL;
g_return_val_if_fail (GTK_IS_SCROLLABLE (scrollable), NULL);
g_object_get (scrollable, "hadjustment", &adj, NULL);
/* Horrid hack; g_object_get() returns a new reference but
* that contradicts the memory management conventions
* for accessors.
*/
if (adj)
g_object_unref (adj);
return adj;
}
/**
* gtk_scrollable_set_hadjustment:
* @scrollable: a #GtkScrollable
* @hadjustment: (allow-none): a #GtkAdjustment
*
* Sets the horizontal adjustment of the #GtkScrollable.
*
* Since: 3.0
**/
void
gtk_scrollable_set_hadjustment (GtkScrollable *scrollable,
GtkAdjustment *hadjustment)
{
g_return_if_fail (GTK_IS_SCROLLABLE (scrollable));
g_return_if_fail (hadjustment == NULL || GTK_IS_ADJUSTMENT (hadjustment));
g_object_set (scrollable, "hadjustment", hadjustment, NULL);
}
/**
* gtk_scrollable_get_vadjustment:
* @scrollable: a #GtkScrollable
*
* Retrieves the #GtkAdjustment used for vertical scrolling.
*
* Return value: (transfer none): vertical #GtkAdjustment.
*
* Since: 3.0
**/
GtkAdjustment *
gtk_scrollable_get_vadjustment (GtkScrollable *scrollable)
{
GtkAdjustment *adj = NULL;
g_return_val_if_fail (GTK_IS_SCROLLABLE (scrollable), NULL);
g_object_get (scrollable, "vadjustment", &adj, NULL);
/* Horrid hack; g_object_get() returns a new reference but
* that contradicts the memory management conventions
* for accessors.
*/
if (adj)
g_object_unref (adj);
return adj;
}
/**
* gtk_scrollable_set_vadjustment:
* @scrollable: a #GtkScrollable
* @vadjustment: (allow-none): a #GtkAdjustment
*
* Sets the vertical adjustment of the #GtkScrollable.
*
* Since: 3.0
**/
void
gtk_scrollable_set_vadjustment (GtkScrollable *scrollable,
GtkAdjustment *vadjustment)
{
g_return_if_fail (GTK_IS_SCROLLABLE (scrollable));
g_return_if_fail (vadjustment == NULL || GTK_IS_ADJUSTMENT (vadjustment));
g_object_set (scrollable, "vadjustment", vadjustment, NULL);
}
/**
* gtk_scrollable_get_hscroll_policy:
* @scrollable: a #GtkScrollable
*
* Gets the horizontal #GtkScrollablePolicy.
*
* Return value: The horizontal #GtkScrollablePolicy.
*
* Since: 3.0
**/
GtkScrollablePolicy
gtk_scrollable_get_hscroll_policy (GtkScrollable *scrollable)
{
GtkScrollablePolicy policy;
g_return_val_if_fail (GTK_IS_SCROLLABLE (scrollable), GTK_SCROLL_MINIMUM);
g_object_get (scrollable, "hscroll-policy", &policy, NULL);
return policy;
}
/**
* gtk_scrollable_set_hscroll_policy:
* @scrollable: a #GtkScrollable
* @policy: the horizontal #GtkScrollablePolicy
*
* Sets the #GtkScrollablePolicy to determine whether
* horizontal scrolling should start below the minimum width or
* below the natural width.
*
* Since: 3.0
**/
void
gtk_scrollable_set_hscroll_policy (GtkScrollable *scrollable,
GtkScrollablePolicy policy)
{
g_return_if_fail (GTK_IS_SCROLLABLE (scrollable));
g_object_set (scrollable, "hscroll-policy", policy, NULL);
}
/**
* gtk_scrollable_get_vscroll_policy:
* @scrollable: a #GtkScrollable
*
* Gets the vertical #GtkScrollablePolicy.
*
* Return value: The vertical #GtkScrollablePolicy.
*
* Since: 3.0
**/
GtkScrollablePolicy
gtk_scrollable_get_vscroll_policy (GtkScrollable *scrollable)
{
GtkScrollablePolicy policy;
g_return_val_if_fail (GTK_IS_SCROLLABLE (scrollable), GTK_SCROLL_MINIMUM);
g_object_get (scrollable, "vscroll-policy", &policy, NULL);
return policy;
}
/**
* gtk_scrollable_set_vscroll_policy:
* @scrollable: a #GtkScrollable
* @policy: the vertical #GtkScrollablePolicy
*
* Sets the #GtkScrollablePolicy to determine whether
* vertical scrolling should start below the minimum height or
* below the natural height.
*
* Since: 3.0
**/
void
gtk_scrollable_set_vscroll_policy (GtkScrollable *scrollable,
GtkScrollablePolicy policy)
{
g_return_if_fail (GTK_IS_SCROLLABLE (scrollable));
g_object_set (scrollable, "vscroll-policy", policy, NULL);
}