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mutter/clutter/clutter/clutter-path-constraint.c

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/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Copyright (C) 2010 Intel Corporation.
*
* 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/>.
*
* Author:
* Emmanuele Bassi <ebassi@linux.intel.com>
*/
/**
* SECTION:clutter-path-constraint
* @Title: ClutterPathConstraint
* @Short_Description: A constraint that follows a path
*
* #ClutterPathConstraint is a simple constraint that modifies the allocation
* of the #ClutterActor to which it has been applied using a #ClutterPath.
*
* By setting the #ClutterPathConstraint:offset property it is possible to
* control how far along the path the #ClutterActor should be.
*
* ClutterPathConstraint is available since Clutter 1.6.
*/
#include "clutter-build-config.h"
#include "clutter-path-constraint.h"
#include "clutter-debug.h"
#include "clutter-marshal.h"
#include "clutter-private.h"
#define CLUTTER_PATH_CONSTRAINT_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), CLUTTER_TYPE_PATH_CONSTRAINT, ClutterPathConstraintClass))
#define CLUTTER_IS_PATH_CONSTRAINT_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), CLUTTER_TYPE_PATH_CONSTRAINT))
#define CLUTTER_PATH_CONSTRAINT_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), CLUTTER_TYPE_PATH_CONSTRAINT, ClutterPathConstraintClass))
struct _ClutterPathConstraint
{
ClutterConstraint parent_instance;
ClutterPath *path;
gfloat offset;
ClutterActor *actor;
guint current_node;
};
struct _ClutterPathConstraintClass
{
ClutterConstraintClass parent_class;
};
enum
{
PROP_0,
PROP_PATH,
PROP_OFFSET,
LAST_PROPERTY
};
enum
{
NODE_REACHED,
LAST_SIGNAL
};
G_DEFINE_TYPE (ClutterPathConstraint, clutter_path_constraint, CLUTTER_TYPE_CONSTRAINT);
static GParamSpec *path_properties[LAST_PROPERTY] = { NULL, };
static guint path_signals[LAST_SIGNAL] = { 0, };
static void
clutter_path_constraint_update_allocation (ClutterConstraint *constraint,
ClutterActor *actor,
ClutterActorBox *allocation)
{
ClutterPathConstraint *self = CLUTTER_PATH_CONSTRAINT (constraint);
gfloat width, height;
ClutterKnot position;
guint knot_id;
if (self->path == NULL)
return;
knot_id = clutter_path_get_position (self->path, self->offset, &position);
clutter_actor_box_get_size (allocation, &width, &height);
allocation->x1 = position.x;
allocation->y1 = position.y;
allocation->x2 = allocation->x1 + width;
allocation->y2 = allocation->y1 + height;
if (knot_id != self->current_node)
{
self->current_node = knot_id;
g_signal_emit (self, path_signals[NODE_REACHED], 0,
self->actor,
self->current_node);
}
}
static void
clutter_path_constraint_set_actor (ClutterActorMeta *meta,
ClutterActor *new_actor)
{
ClutterPathConstraint *path = CLUTTER_PATH_CONSTRAINT (meta);
ClutterActorMetaClass *parent;
/* store the pointer to the actor, for later use */
path->actor = new_actor;
parent = CLUTTER_ACTOR_META_CLASS (clutter_path_constraint_parent_class);
parent->set_actor (meta, new_actor);
}
static void
clutter_path_constraint_dispose (GObject *gobject)
{
ClutterPathConstraint *self = CLUTTER_PATH_CONSTRAINT (gobject);
if (self->path != NULL)
{
g_object_unref (self->path);
self->path = NULL;
}
G_OBJECT_CLASS (clutter_path_constraint_parent_class)->dispose (gobject);
}
static void
clutter_path_constraint_set_property (GObject *gobject,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
ClutterPathConstraint *self = CLUTTER_PATH_CONSTRAINT (gobject);
switch (prop_id)
{
case PROP_PATH:
clutter_path_constraint_set_path (self, g_value_get_object (value));
break;
case PROP_OFFSET:
clutter_path_constraint_set_offset (self, g_value_get_float (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
}
}
static void
clutter_path_constraint_get_property (GObject *gobject,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
ClutterPathConstraint *self = CLUTTER_PATH_CONSTRAINT (gobject);
switch (prop_id)
{
case PROP_PATH:
g_value_set_object (value, self->path);
break;
case PROP_OFFSET:
g_value_set_float (value, self->offset);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
}
}
static void
clutter_path_constraint_class_init (ClutterPathConstraintClass *klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
ClutterActorMetaClass *meta_class = CLUTTER_ACTOR_META_CLASS (klass);
ClutterConstraintClass *constraint_class = CLUTTER_CONSTRAINT_CLASS (klass);
/**
* ClutterPathConstraint:path:
*
* The #ClutterPath used to constrain the position of an actor.
*
* Since: 1.6
*/
path_properties[PROP_PATH] =
g_param_spec_object ("path",
P_("Path"),
P_("The path used to constrain an actor"),
CLUTTER_TYPE_PATH,
CLUTTER_PARAM_READWRITE);
/**
* ClutterPathConstraint:offset:
*
* The offset along the #ClutterPathConstraint:path, between -1.0 and 2.0.
*
* Since: 1.6
*/
path_properties[PROP_OFFSET] =
g_param_spec_float ("offset",
P_("Offset"),
P_("The offset along the path, between -1.0 and 2.0"),
-1.0, 2.0,
0.0,
CLUTTER_PARAM_READWRITE);
gobject_class->set_property = clutter_path_constraint_set_property;
gobject_class->get_property = clutter_path_constraint_get_property;
gobject_class->dispose = clutter_path_constraint_dispose;
g_object_class_install_properties (gobject_class,
LAST_PROPERTY,
path_properties);
meta_class->set_actor = clutter_path_constraint_set_actor;
constraint_class->update_allocation = clutter_path_constraint_update_allocation;
/**
* ClutterPathConstraint::node-reached:
* @constraint: the #ClutterPathConstraint that emitted the signal
* @actor: the #ClutterActor using the @constraint
* @index: the index of the node that has been reached
*
* The ::node-reached signal is emitted each time a
* #ClutterPathConstraint:offset value results in the actor
* passing a #ClutterPathNode
*
* Since: 1.6
*/
path_signals[NODE_REACHED] =
g_signal_new (I_("node-reached"),
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
0,
NULL, NULL,
_clutter_marshal_VOID__OBJECT_UINT,
G_TYPE_NONE, 2,
CLUTTER_TYPE_ACTOR,
G_TYPE_UINT);
}
static void
clutter_path_constraint_init (ClutterPathConstraint *self)
{
self->offset = 0.0f;
self->current_node = G_MAXUINT;
}
/**
* clutter_path_constraint_new:
* @path: (allow-none): a #ClutterPath, or %NULL
* @offset: the offset along the #ClutterPath
*
* Creates a new #ClutterPathConstraint with the given @path and @offset
*
* Return value: the newly created #ClutterPathConstraint
*
* Since: 1.6
*/
ClutterConstraint *
clutter_path_constraint_new (ClutterPath *path,
gfloat offset)
{
g_return_val_if_fail (path == NULL || CLUTTER_IS_PATH (path), NULL);
return g_object_new (CLUTTER_TYPE_PATH_CONSTRAINT,
"path", path,
"offset", offset,
NULL);
}
/**
* clutter_path_constraint_set_path:
* @constraint: a #ClutterPathConstraint
* @path: (allow-none): a #ClutterPath
*
* Sets the @path to be followed by the #ClutterPathConstraint.
*
* The @constraint will take ownership of the #ClutterPath passed to this
* function.
*
* Since: 1.6
*/
void
clutter_path_constraint_set_path (ClutterPathConstraint *constraint,
ClutterPath *path)
{
g_return_if_fail (CLUTTER_IS_PATH_CONSTRAINT (constraint));
g_return_if_fail (path == NULL || CLUTTER_IS_PATH (path));
if (constraint->path == path)
return;
if (constraint->path != NULL)
{
g_object_unref (constraint->path);
constraint->path = NULL;
}
if (path != NULL)
constraint->path = g_object_ref_sink (path);
if (constraint->actor != NULL)
clutter_actor_queue_relayout (constraint->actor);
g_object_notify_by_pspec (G_OBJECT (constraint), path_properties[PROP_PATH]);
}
/**
* clutter_path_constraint_get_path:
* @constraint: a #ClutterPathConstraint
*
* Retrieves a pointer to the #ClutterPath used by @constraint.
*
* Return value: (transfer none): the #ClutterPath used by the
* #ClutterPathConstraint, or %NULL. The returned #ClutterPath is owned
* by the constraint and it should not be unreferenced
*
* Since: 1.6
*/
ClutterPath *
clutter_path_constraint_get_path (ClutterPathConstraint *constraint)
{
g_return_val_if_fail (CLUTTER_IS_PATH_CONSTRAINT (constraint), NULL);
return constraint->path;
}
/**
* clutter_path_constraint_set_offset:
* @constraint: a #ClutterPathConstraint
* @offset: the offset along the path
*
* Sets the offset along the #ClutterPath used by @constraint.
*
* Since: 1.6
*/
void
clutter_path_constraint_set_offset (ClutterPathConstraint *constraint,
gfloat offset)
{
g_return_if_fail (CLUTTER_IS_PATH_CONSTRAINT (constraint));
if (constraint->offset == offset)
return;
constraint->offset = offset;
if (constraint->actor != NULL)
clutter_actor_queue_relayout (constraint->actor);
g_object_notify_by_pspec (G_OBJECT (constraint), path_properties[PROP_OFFSET]);
}
/**
* clutter_path_constraint_get_offset:
* @constraint: a #ClutterPathConstraint
*
* Retrieves the offset along the #ClutterPath used by @constraint.
*
* Return value: the offset
*
* Since: 1.6
*/
gfloat
clutter_path_constraint_get_offset (ClutterPathConstraint *constraint)
{
g_return_val_if_fail (CLUTTER_IS_PATH_CONSTRAINT (constraint), 0.0);
return constraint->offset;
}
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