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d096a3c791
If a sub-class of LayoutManager wishes to implement a parametrized layout policy it also needs a way to notify the container using the layout manager that the layout has changed. We cannot do it directly and automatically from the LayoutManager because a) it has no back link to the actor that it is using it and b) it can be attached to multiple actors. This is a job for <cue raising dramatic music> signals! By adding ClutterLayoutManager::layout-changed (and its relative emitted function) we can notify actors using the layout manager that the layout parameters have been changed, and thus they should queue a relayout.
284 lines
9.7 KiB
C
284 lines
9.7 KiB
C
/*
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* Clutter.
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*
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* An OpenGL based 'interactive canvas' library.
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*
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* Copyright (C) 2009 Intel Corporation.
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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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* Author:
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* Emmanuele Bassi <ebassi@linux.intel.com>
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*/
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/**
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* SECTION:clutter-layout-manager
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* @short_description: Layout managers base class
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*
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* #ClutterLayoutManager is a base abstract class for layout managers. A
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* layout manager implements the layouting policy for a composite or a
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* container actor: it controls the preferred size of the actor to which
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* it has been paired, and it controls the allocation of its children.
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*
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* Any composite or container #ClutterActor subclass can delegate the
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* layouting of its children to a #ClutterLayoutManager. Clutter provides
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* a generic container using #ClutterLayoutManager called #ClutterBox.
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*
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* Clutter provides some simple #ClutterLayoutManager sub-classes, like
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* #ClutterFixedLayout and #ClutterBinLayout.
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*
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* #ClutterLayoutManager is available since Clutter 1.2
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "clutter-debug.h"
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#include "clutter-layout-manager.h"
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#include "clutter-marshal.h"
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#include "clutter-private.h"
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#define LAYOUT_MANAGER_WARN_NOT_IMPLEMENTED(m,method) G_STMT_START { \
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GObject *_obj = G_OBJECT (m); \
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g_warning ("Layout managers of type %s do not implement " \
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"the ClutterLayoutManager::%s method", \
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G_OBJECT_TYPE_NAME (_obj), \
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(method)); } G_STMT_END
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enum
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{
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LAYOUT_CHANGED,
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LAST_SIGNAL
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};
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G_DEFINE_ABSTRACT_TYPE (ClutterLayoutManager,
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clutter_layout_manager,
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G_TYPE_INITIALLY_UNOWNED);
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static guint manager_signals[LAST_SIGNAL] = { 0, };
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static void
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layout_manager_real_get_preferred_width (ClutterLayoutManager *manager,
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ClutterContainer *container,
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gfloat for_height,
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gfloat *min_width_p,
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gfloat *nat_width_p)
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{
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LAYOUT_MANAGER_WARN_NOT_IMPLEMENTED (manager, "get_preferred_width");
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if (min_width_p)
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*min_width_p = 0.0;
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if (nat_width_p)
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*nat_width_p = 0.0;
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}
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static void
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layout_manager_real_get_preferred_height (ClutterLayoutManager *manager,
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ClutterContainer *container,
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gfloat for_width,
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gfloat *min_height_p,
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gfloat *nat_height_p)
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{
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LAYOUT_MANAGER_WARN_NOT_IMPLEMENTED (manager, "get_preferred_height");
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if (min_height_p)
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*min_height_p = 0.0;
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if (nat_height_p)
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*nat_height_p = 0.0;
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}
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static void
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layout_manager_real_allocate (ClutterLayoutManager *manager,
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ClutterContainer *container,
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const ClutterActorBox *allocation,
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ClutterAllocationFlags flags)
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{
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LAYOUT_MANAGER_WARN_NOT_IMPLEMENTED (manager, "allocate");
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}
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static void
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clutter_layout_manager_class_init (ClutterLayoutManagerClass *klass)
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{
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klass->get_preferred_width = layout_manager_real_get_preferred_width;
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klass->get_preferred_height = layout_manager_real_get_preferred_height;
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klass->allocate = layout_manager_real_allocate;
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/**
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* ClutterLayoutManager::layout-changed:
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* @manager: the #ClutterLayoutManager that emitted the signal
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*
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* The ::layout-changed signal is emitted each time a layout manager
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* has been changed. Every #ClutterActor using the @manager instance
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* as a layout manager should connect a handler to the ::layout-changed
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* signal and queue a relayout on themselves:
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*
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* |[
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* static void layout_changed (ClutterLayoutManager *manager,
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* ClutterActor *self)
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* {
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* clutter_actor_queue_relayout (self);
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* }
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* ...
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* self->manager = g_object_ref_sink (manager);
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* g_signal_connect (self->manager, "layout-changed",
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* G_CALLBACK (layout_changed),
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* self);
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* ]|
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*
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* Sub-classes of #ClutterLayoutManager that implement a layout that
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* can be controlled or changed using parameters should emit the
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* ::layout-changed signal whenever one of the parameters changes,
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* by using clutter_layout_manager_layout_changed().
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*
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* Since: 1.2
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*/
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manager_signals[LAYOUT_CHANGED] =
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g_signal_new (I_("layout-changed"),
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G_TYPE_FROM_CLASS (klass),
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G_SIGNAL_RUN_LAST,
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G_STRUCT_OFFSET (ClutterLayoutManagerClass,
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layout_changed),
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NULL, NULL,
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clutter_marshal_VOID__VOID,
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G_TYPE_NONE, 0);
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}
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static void
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clutter_layout_manager_init (ClutterLayoutManager *manager)
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{
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}
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/**
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* clutter_layout_manager_get_preferred_width:
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* @manager: a #ClutterLayoutManager
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* @container: the #ClutterContainer using @manager
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* @for_height: the height for which the width should be computed, or -1
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* @min_width_p: (out) (allow-none): return location for the minimum width
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* of the layout, or %NULL
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* @nat_width_p: (out) (allow-none): return location for the natural width
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* of the layout, or %NULL
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*
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* Computes the minimum and natural widths of the @container according
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* to @manager.
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*
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* See also clutter_actor_get_preferred_width()
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*
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* Since: 1.2
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*/
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void
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clutter_layout_manager_get_preferred_width (ClutterLayoutManager *manager,
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ClutterContainer *container,
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gfloat for_height,
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gfloat *min_width_p,
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gfloat *nat_width_p)
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{
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ClutterLayoutManagerClass *klass;
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g_return_if_fail (CLUTTER_IS_LAYOUT_MANAGER (manager));
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g_return_if_fail (CLUTTER_IS_CONTAINER (container));
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klass = CLUTTER_LAYOUT_MANAGER_GET_CLASS (manager);
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klass->get_preferred_width (manager, container, for_height,
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min_width_p,
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nat_width_p);
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}
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/**
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* clutter_layout_manager_get_preferred_height:
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* @manager: a #ClutterLayoutManager
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* @container: the #ClutterContainer using @manager
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* @for_width: the width for which the height should be computed, or -1
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* @min_height_p: (out) (allow-none): return location for the minimum height
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* of the layout, or %NULL
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* @nat_height_p: (out) (allow-none): return location for the natural height
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* of the layout, or %NULL
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*
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* Computes the minimum and natural heights of the @container according
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* to @manager.
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*
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* See also clutter_actor_get_preferred_height()
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*
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* Since: 1.2
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*/
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void
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clutter_layout_manager_get_preferred_height (ClutterLayoutManager *manager,
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ClutterContainer *container,
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gfloat for_width,
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gfloat *min_height_p,
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gfloat *nat_height_p)
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{
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ClutterLayoutManagerClass *klass;
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g_return_if_fail (CLUTTER_IS_LAYOUT_MANAGER (manager));
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g_return_if_fail (CLUTTER_IS_CONTAINER (container));
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klass = CLUTTER_LAYOUT_MANAGER_GET_CLASS (manager);
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klass->get_preferred_height (manager, container, for_width,
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min_height_p,
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nat_height_p);
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}
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/**
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* clutter_layout_manager_allocate:
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* @manager: a #ClutterLayoutManager
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* @container: the #ClutterContainer using @manager
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* @allocation: the #ClutterActorBox containing the allocated area
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* of @container
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* @flags: the allocation flags
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*
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* Allocates the children of @container given an area
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*
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* See also clutter_actor_allocate()
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*
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* Since: 1.2
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*/
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void
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clutter_layout_manager_allocate (ClutterLayoutManager *manager,
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ClutterContainer *container,
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const ClutterActorBox *allocation,
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ClutterAllocationFlags flags)
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{
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ClutterLayoutManagerClass *klass;
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g_return_if_fail (CLUTTER_IS_LAYOUT_MANAGER (manager));
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g_return_if_fail (CLUTTER_IS_CONTAINER (container));
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g_return_if_fail (allocation != NULL);
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klass = CLUTTER_LAYOUT_MANAGER_GET_CLASS (manager);
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klass->allocate (manager, container, allocation, flags);
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}
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/**
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* clutter_layout_manager_layout_changed:
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* @manager: a #ClutterLayoutManager
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*
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* Emits the #ClutterLayoutManager::layout-changed signal on @manager
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*
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* This function should only be called by implementations of the
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* #ClutterLayoutManager class
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*
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* Since: 1.2
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*/
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void
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clutter_layout_manager_layout_changed (ClutterLayoutManager *manager)
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{
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g_return_if_fail (CLUTTER_IS_LAYOUT_MANAGER (manager));
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g_signal_emit (manager, manager_signals[LAYOUT_CHANGED], 0);
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}
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