mutter/clutter/clutter-behaviour.c
Emmanuele Bassi d6d208da7d Remove Units from the public API
With the recent change to internal floating point values, ClutterUnit
has become a redundant type, defined to be a float. All integer entry
points are being internally converted to floating point values to be
passed to the GL pipeline with the least amount of conversion.

ClutterUnit is thus exposed as just a "pixel with fractionary bits",
and not -- as users might think -- as generic, resolution and device
independent units. not that it was the case, but a definitive amount
of people was convinced it did provide this "feature", and was flummoxed
about the mere existence of this type.

So, having ClutterUnit exposed in the public API doubles the entry
points and has the following disadvantages:

  - we have to maintain twice the amount of entry points in ClutterActor
  - we still do an integer-to-float implicit conversion
  - we introduce a weird impedance between pixels and "pixels with
    fractionary bits"
  - language bindings will have to choose what to bind, and resort
    to manually overriding the API
    + *except* for language bindings based on GObject-Introspection, as
      they cannot do manual overrides, thus will replicate the entire
      set of entry points

For these reason, we should coalesces every Actor entry point for
pixels and for ClutterUnit into a single entry point taking a float,
like:

  void clutter_actor_set_x (ClutterActor *self,
                            gfloat        x);
  void clutter_actor_get_size (ClutterActor *self,
                               gfloat       *width,
                               gfloat       *height);
  gfloat clutter_actor_get_height (ClutterActor *self);

etc.

The issues I have identified are:

  - we'll have a two cases of compiler warnings:
    - printf() format of the return values from %d to %f
    - clutter_actor_get_size() taking floats instead of unsigned ints
  - we'll have a problem with varargs when passing an integer instead
    of a floating point value, except on 64bit platforms where the
    size of a float is the same as the size of an int

To be clear: the *intent* of the API should not change -- we still use
pixels everywhere -- but:

  - we remove ambiguity in the API with regard to pixels and units
  - we remove entry points we get to maintain for the whole 1.0
    version of the API
  - we make things simpler to bind for both manual language bindings
    and automatic (gobject-introspection based) ones
  - we have the simplest API possible while still exposing the
    capabilities of the underlying GL implementation
2009-05-06 16:44:47 +01:00

671 lines
18 KiB
C

/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Authored By Matthew Allum <mallum@openedhand.com>
*
* Copyright (C) 2006 OpenedHand
*
* 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, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:clutter-behaviour
* @short_description: Class for providing behaviours to actors
*
* #ClutterBehaviour is the base class for implementing behaviours. A
* behaviour is a controller object for #ClutterActor<!-- -->s; you can
* use a behaviour to control one or more properties of an actor (such
* as its opacity, or its position). A #ClutterBehaviour is driven by
* an "alpha function" stored inside a #ClutterAlpha object; an alpha
* function is a function depending solely on time. The alpha function
* computes a value which is then applied to the properties of the
* actors driven by a behaviour.
*
* Clutter provides some pre-defined behaviours, like #ClutterBehaviourPath,
* which controls the position of a set of actors making them "walk" along
* a set of nodes; #ClutterBehaviourOpacity, which controls the opacity
* of a set of actors; #ClutterBehaviourScale, which controls the width
* and height of a set of actors.
*
* To visualize the effects of different alpha functions on a
* #ClutterBehaviour implementation it is possible to take the
* #ClutterBehaviourPath as an example:
*
* <figure id="behaviour-path-alpha">
* <title>Effects of alpha functions on a path</title>
* <graphic fileref="path-alpha-func.png" format="PNG"/>
* </figure>
*
* The actors position between the path's end points directly correlates
* to the #ClutterAlpha's current alpha value driving the behaviour. With
* the #ClutterAlpha's function set to %CLUTTER_ALPHA_RAMP_INC the actor
* will follow the path at a constant velocity, but when changing to
* %CLUTTER_ALPHA_SINE_INC the actor initially accelerates before quickly
* decelerating.
*
* In order to implement a new behaviour you should subclass #ClutterBehaviour
* and override the "alpha_notify" virtual function; inside the overridden
* function you should obtain the alpha value from the #ClutterAlpha
* instance bound to the behaviour and apply it to the desiderd property
* (or properties) of every actor controlled by the behaviour.
*
* #ClutterBehaviour is available since Clutter 0.2
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "clutter-main.h"
#include "clutter-actor.h"
#include "clutter-behaviour.h"
#include "clutter-debug.h"
#include "clutter-private.h"
#include "clutter-marshal.h"
/**
* clutter_knot_copy:
* @knot: a #ClutterKnot
*
* Makes an allocated copy of a knot.
*
* Return value: the copied knot.
*
* Since: 0.2
*/
ClutterKnot *
clutter_knot_copy (const ClutterKnot *knot)
{
ClutterKnot *copy;
copy = g_slice_new0 (ClutterKnot);
*copy = *knot;
return copy;
}
/**
* clutter_knot_free:
* @knot: a #ClutterKnot
*
* Frees the memory of an allocated knot.
*
* Since: 0.2
*/
void
clutter_knot_free (ClutterKnot *knot)
{
if (G_LIKELY (knot))
{
g_slice_free (ClutterKnot, knot);
}
}
/**
* clutter_knot_equal:
* @knot_a: First knot
* @knot_b: Second knot
*
* Compares to knot and checks if the point to the same location.
*
* Return value: %TRUE if the knots point to the same location.
*
* Since: 0.2
*/
gboolean
clutter_knot_equal (const ClutterKnot *knot_a,
const ClutterKnot *knot_b)
{
g_return_val_if_fail (knot_a != NULL, FALSE);
g_return_val_if_fail (knot_b != NULL, FALSE);
if (knot_a == knot_b)
return TRUE;
return knot_a->x == knot_b->x && knot_a->y == knot_b->y;
}
GType
clutter_knot_get_type (void)
{
static GType our_type = 0;
if (G_UNLIKELY (!our_type))
{
our_type =
g_boxed_type_register_static (I_("ClutterKnot"),
(GBoxedCopyFunc) clutter_knot_copy,
(GBoxedFreeFunc) clutter_knot_free);
}
return our_type;
}
G_DEFINE_ABSTRACT_TYPE (ClutterBehaviour,
clutter_behaviour,
G_TYPE_OBJECT);
struct _ClutterBehaviourPrivate
{
ClutterAlpha *alpha;
guint notify_id;
GSList *actors;
};
enum
{
PROP_0,
PROP_ALPHA
};
enum {
APPLIED,
REMOVED,
LAST_SIGNAL
};
static guint behave_signals[LAST_SIGNAL] = { 0 };
#define CLUTTER_BEHAVIOUR_GET_PRIVATE(obj) \
(G_TYPE_INSTANCE_GET_PRIVATE ((obj), \
CLUTTER_TYPE_BEHAVIOUR, \
ClutterBehaviourPrivate))
static void
clutter_behaviour_dispose (GObject *gobject)
{
ClutterBehaviour *self = CLUTTER_BEHAVIOUR (gobject);
clutter_behaviour_set_alpha (self, NULL);
clutter_behaviour_remove_all (self);
G_OBJECT_CLASS (clutter_behaviour_parent_class)->dispose (gobject);
}
static void
clutter_behaviour_set_property (GObject *object,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
ClutterBehaviour *behaviour = CLUTTER_BEHAVIOUR (object);
switch (prop_id)
{
case PROP_ALPHA:
clutter_behaviour_set_alpha (behaviour, g_value_get_object (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
clutter_behaviour_get_property (GObject *object,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
ClutterBehaviour *behaviour = CLUTTER_BEHAVIOUR (object);
ClutterBehaviourPrivate *priv = behaviour->priv;
switch (prop_id)
{
case PROP_ALPHA:
g_value_set_object (value, priv->alpha);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
clutter_behaviour_alpha_notify_unimplemented (ClutterBehaviour *behaviour,
gdouble alpha_value)
{
g_warning ("ClutterBehaviourClass::alpha_notify not implemented for '%s'",
g_type_name (G_TYPE_FROM_INSTANCE (behaviour)));
}
static void
clutter_behaviour_class_init (ClutterBehaviourClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
object_class->dispose = clutter_behaviour_dispose;
object_class->set_property = clutter_behaviour_set_property;
object_class->get_property = clutter_behaviour_get_property;
/**
* ClutterBehaviour:alpha:
*
* The #ClutterAlpha object used to drive this behaviour. A #ClutterAlpha
* object binds a #ClutterTimeline and a function which computes a value
* (the "alpha") depending on the time. Each time the alpha value changes
* the alpha-notify virtual function is called.
*
* Since: 0.2
*/
g_object_class_install_property (object_class,
PROP_ALPHA,
g_param_spec_object ("alpha",
"Alpha",
"Alpha Object to drive the behaviour",
CLUTTER_TYPE_ALPHA,
CLUTTER_PARAM_READWRITE));
klass->alpha_notify = clutter_behaviour_alpha_notify_unimplemented;
/**
* ClutterBehaviour::applied:
* @behaviour: the #ClutterBehaviour that received the signal
* @actor: the actor the behaviour was applied to.
*
* The ::apply signal is emitted each time the behaviour is applied
* to an actor.
*
* Since: 0.4
*/
behave_signals[APPLIED] =
g_signal_new ("applied",
G_OBJECT_CLASS_TYPE (object_class),
G_SIGNAL_RUN_FIRST,
G_STRUCT_OFFSET (ClutterBehaviourClass, applied),
NULL, NULL,
clutter_marshal_VOID__OBJECT,
G_TYPE_NONE, 1,
CLUTTER_TYPE_ACTOR);
/**
* ClutterBehaviour::removed:
* @behaviour: the #ClutterBehaviour that received the signal
* @actor: the removed actor
*
* The ::removed signal is emitted each time a behaviour is not applied
* to an actor anymore.
*
*/
behave_signals[REMOVED] =
g_signal_new ("removed",
G_OBJECT_CLASS_TYPE (object_class),
G_SIGNAL_RUN_FIRST,
G_STRUCT_OFFSET (ClutterBehaviourClass, removed),
NULL, NULL,
clutter_marshal_VOID__OBJECT,
G_TYPE_NONE, 1,
CLUTTER_TYPE_ACTOR);
g_type_class_add_private (klass, sizeof (ClutterBehaviourPrivate));
}
static void
clutter_behaviour_init (ClutterBehaviour *self)
{
ClutterBehaviourPrivate *priv;
self->priv = priv = CLUTTER_BEHAVIOUR_GET_PRIVATE (self);
}
static void
remove_actor_on_destroy (ClutterActor *actor,
ClutterBehaviour *behaviour)
{
clutter_behaviour_remove (behaviour, actor);
}
/**
* clutter_behaviour_apply:
* @behave: a #ClutterBehaviour
* @actor: a #ClutterActor
*
* Applies @behave to @actor. This function adds a reference on
* the actor.
*
* Since: 0.2
*/
void
clutter_behaviour_apply (ClutterBehaviour *behave,
ClutterActor *actor)
{
ClutterBehaviourPrivate *priv;
g_return_if_fail (CLUTTER_IS_BEHAVIOUR (behave));
g_return_if_fail (CLUTTER_IS_ACTOR (actor));
priv = behave->priv;
if (g_slist_find (priv->actors, actor))
{
g_warning ("The behaviour of type %s already applies "
"to the actor of type %s",
g_type_name (G_OBJECT_TYPE (behave)),
g_type_name (G_OBJECT_TYPE (actor)));
return;
}
priv->actors = g_slist_append (priv->actors, g_object_ref (actor));
g_signal_connect (actor, "destroy",
G_CALLBACK (remove_actor_on_destroy),
behave);
g_signal_emit (behave, behave_signals[APPLIED], 0, actor);
}
/**
* clutter_behaviour_is_applied:
* @behave: a #ClutterBehaviour
* @actor: a #ClutterActor
*
* Check if @behave applied to @actor.
*
* Return value: TRUE if actor has behaviour. FALSE otherwise.
*
* Since: 0.4
*/
gboolean
clutter_behaviour_is_applied (ClutterBehaviour *behave,
ClutterActor *actor)
{
g_return_val_if_fail (CLUTTER_IS_BEHAVIOUR (behave), FALSE);
g_return_val_if_fail (CLUTTER_IS_ACTOR (actor), FALSE);
return (g_slist_find (behave->priv->actors, actor) != NULL);
}
/**
* clutter_behaviour_remove:
* @behave: a #ClutterBehaviour
* @actor: a #ClutterActor
*
* Removes @actor from the list of #ClutterActor<!-- -->s to which
* @behave applies. This function removes a reference on the actor.
*
* Since: 0.2
*/
void
clutter_behaviour_remove (ClutterBehaviour *behave,
ClutterActor *actor)
{
ClutterBehaviourPrivate *priv;
g_return_if_fail (CLUTTER_IS_BEHAVIOUR (behave));
g_return_if_fail (CLUTTER_IS_ACTOR (actor));
priv = behave->priv;
if (!g_slist_find (priv->actors, actor))
{
g_warning ("The behaviour of type %s is not applied "
"to the actor of type %s",
g_type_name (G_OBJECT_TYPE (behave)),
g_type_name (G_OBJECT_TYPE (actor)));
return;
}
g_signal_handlers_disconnect_by_func (actor,
G_CALLBACK (remove_actor_on_destroy),
behave);
priv->actors = g_slist_remove (priv->actors, actor);
g_signal_emit (behave, behave_signals[REMOVED], 0, actor);
g_object_unref (actor);
}
/**
* clutter_behaviour_get_n_actors:
* @behave: a #ClutterBehaviour
*
* Gets the number of actors this behaviour is applied too.
*
* Return value: The number of applied actors
*
* Since: 0.2
*/
gint
clutter_behaviour_get_n_actors (ClutterBehaviour *behave)
{
g_return_val_if_fail (CLUTTER_IS_BEHAVIOUR (behave), 0);
return g_slist_length (behave->priv->actors);
}
/**
* clutter_behaviour_get_nth_actor:
* @behave: a #ClutterBehaviour
* @index_: the index of an actor this behaviour is applied too.
*
* Gets an actor the behaviour was applied to referenced by index num.
*
* Return value: (transfer none): A Clutter actor or NULL if @index_ is invalid.
*
* Since: 0.2
*/
ClutterActor*
clutter_behaviour_get_nth_actor (ClutterBehaviour *behave,
gint index_)
{
g_return_val_if_fail (CLUTTER_IS_BEHAVIOUR (behave), NULL);
return g_slist_nth_data (behave->priv->actors, index_);
}
/**
* clutter_behaviour_actors_foreach:
* @behave: a #ClutterBehaviour
* @func: a function called for each actor
* @data: optional data to be passed to the function, or %NULL
*
* Calls @func for every actor driven by @behave.
*
* Since: 0.2
*/
void
clutter_behaviour_actors_foreach (ClutterBehaviour *behave,
ClutterBehaviourForeachFunc func,
gpointer data)
{
GSList *l;
g_return_if_fail (CLUTTER_IS_BEHAVIOUR (behave));
g_return_if_fail (func != NULL);
for (l = behave->priv->actors; l != NULL; l = l->next)
{
ClutterActor *actor = l->data;
g_assert (CLUTTER_IS_ACTOR (actor));
func (behave, actor, data);
}
}
/**
* clutter_behaviour_get_alpha:
* @behave: a #ClutterBehaviour
*
* Retrieves the #ClutterAlpha object bound to @behave.
*
* Return value: (transfer none): a #ClutterAlpha object, or %NULL if no alpha
* object has been bound to this behaviour.
*
* Since: 0.2
*/
ClutterAlpha *
clutter_behaviour_get_alpha (ClutterBehaviour *behave)
{
g_return_val_if_fail (CLUTTER_IS_BEHAVIOUR (behave), NULL);
return behave->priv->alpha;
}
static void
notify_cb (GObject *object,
GParamSpec *param_spec,
ClutterBehaviour *behave)
{
ClutterBehaviourClass *klass;
klass = CLUTTER_BEHAVIOUR_GET_CLASS (behave);
CLUTTER_NOTE (BEHAVIOUR, "notify::alpha");
/* no actors, we can stop right here */
if (behave->priv->actors == NULL)
return;
if (klass->alpha_notify)
{
gdouble alpha_value = clutter_alpha_get_alpha (behave->priv->alpha);
CLUTTER_NOTE (BEHAVIOUR, "calling %s::alpha_notify (%p, %.4f)",
g_type_name (G_TYPE_FROM_CLASS (klass)),
behave, alpha_value);
klass->alpha_notify (behave, alpha_value);
}
}
/**
* clutter_behaviour_set_alpha:
* @behave: a #ClutterBehaviour
* @alpha: a #ClutterAlpha or %NULL to unset a previously set alpha
*
* Binds @alpha to a #ClutterBehaviour. The #ClutterAlpha object
* is what makes a behaviour work: for each tick of the timeline
* used by #ClutterAlpha a new value of the alpha parameter is
* computed by the alpha function; the value should be used by
* the #ClutterBehaviour to update one or more properties of the
* actors to which the behaviour applies.
*
* If @alpha is not %NULL, the #ClutterBehaviour will take ownership
* of the #ClutterAlpha instance.
*
* Since: 0.2
*/
void
clutter_behaviour_set_alpha (ClutterBehaviour *behave,
ClutterAlpha *alpha)
{
ClutterBehaviourPrivate *priv;
g_return_if_fail (CLUTTER_IS_BEHAVIOUR (behave));
g_return_if_fail (alpha == NULL || CLUTTER_IS_ALPHA (alpha));
priv = behave->priv;
if (alpha)
g_object_ref_sink (alpha);
if (priv->notify_id)
{
CLUTTER_NOTE (BEHAVIOUR, "removing previous notify-id (%d)",
priv->notify_id);
g_signal_handler_disconnect (priv->alpha, priv->notify_id);
priv->notify_id = 0;
}
if (priv->alpha)
{
CLUTTER_NOTE (BEHAVIOUR, "removing previous alpha object");
g_object_unref (priv->alpha);
priv->alpha = NULL;
}
if (alpha)
{
priv->alpha = alpha;
priv->notify_id = g_signal_connect (priv->alpha, "notify::alpha",
G_CALLBACK(notify_cb),
behave);
CLUTTER_NOTE (BEHAVIOUR, "setting new alpha object (%p, notify:%d)",
priv->alpha, priv->notify_id);
}
}
/**
* clutter_behaviour_get_actors:
* @behave: a #ClutterBehaviour
*
* Retrieves all the actors to which @behave applies. It is not recommended
* for derived classes to use this in there alpha notify method but use
* #clutter_behaviour_actors_foreach as it avoids alot of needless allocations.
*
* Return value: (transfer container) (element-type ClutterActor): a list of actors.
* You should free the returned list with g_slist_free() when finished using it.
*
* Since: 0.2
*/
GSList *
clutter_behaviour_get_actors (ClutterBehaviour *behave)
{
ClutterBehaviourPrivate *priv;
GSList *retval, *l;
g_return_val_if_fail (CLUTTER_BEHAVIOUR (behave), NULL);
priv = behave->priv;
retval = NULL;
for (l = priv->actors; l != NULL; l = l->next)
retval = g_slist_prepend (retval, l->data);
return g_slist_reverse (retval);
}
/**
* clutter_behaviour_remove_all:
* @behave: a #ClutterBehaviour
*
* Removes every actor from the list that @behave holds.
*
* Since: 0.4
*/
void
clutter_behaviour_remove_all (ClutterBehaviour *behave)
{
ClutterBehaviourPrivate *priv;
GSList *l;
g_return_if_fail (CLUTTER_IS_BEHAVIOUR (behave));
priv = behave->priv;
for (l = priv->actors; l != NULL; l = l->next)
{
ClutterActor *actor = l->data;
g_signal_emit (behave, behave_signals[REMOVED], 0, actor);
g_signal_handlers_disconnect_by_func (actor,
G_CALLBACK (remove_actor_on_destroy),
behave);
g_object_unref (actor);
}
g_slist_free (priv->actors);
priv->actors = NULL;
}