Actor bounding box and transformations

Any actor's 2D surface is contained inside its bounding box, as described by the ClutterActorBox structure:

Figure 1. Bounding box of an Actor

The actor box represents the untransformed area occupied by an actor. Each visible actor that has been put on a ClutterStage also has a transformed area, depending on the actual transformations applied to it by the developer (scale, rotation). Tranforms will also be applied to any child actors. Also applied to all actors by the ClutterStage is a perspective transformation. API is provided for both tranformed and untransformed actor geometry information.

The GL 'modelview' transform matrix for the actor is constructed from the actor settings by the following order of operations:

An actor can either be explicitly sized and positioned, using the various size and position accessors, like clutter_actor_set_x() or clutter_actor_set_width(); or it can have a preferred width and height, which then allows a layout manager to implicitly size and position it by "allocating" an area for an actor. This allows for actors to be manipulated in both a fixed (or static) parent container (i.e. children of ClutterGroup) and a more automatic (or dynamic) layout based parent container.

When accessing the position and size of an actor, the simple accessors like clutter_actor_get_width() and clutter_actor_get_x() will return a value depending on whether the actor has been explicitly sized and positioned by the developer or implicitly by the layout manager.

Depending on whether you are querying an actor or implementing a layout manager, you should either use the simple accessors or use the size negotiation API.

Event Handling

Clutter actors are also able to receive input events and react to them. Events are handled in the following ways:

Figure 2. Event flow in Clutter

Every '?' box in the diagram above is an entry point for application code.

Implementing a ClutterActor

For implementing a new custom actor class, please read the corresponding section of the API reference.

ClutterActor custom properties for ClutterScript

ClutterActor defines a custom "rotation" property which allows a short-hand description of the rotations to be applied to an actor.

The syntax of the "rotation" property is the following:

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"rotation" : [
  { "<axis>" : [ <angle>, [ <center> ] ] }
]

where the axis is the name of an enumeration value of type ClutterRotateAxis and angle is a floating point value representing the rotation angle on the given axis, in degrees.

The center array is optional, and if present it must contain the center of rotation as described by two coordinates: Y and Z for "x-axis"; X and Z for "y-axis"; and X and Y for "z-axis".

ClutterActor will also parse every positional and dimensional property defined as a string through clutter_units_from_string(); you should read the documentation for the ClutterUnits parser format for the valid units and syntax.

CLUTTER_ACTOR_SET_FLAGS()

#define CLUTTER_ACTOR_SET_FLAGS(a,f)    (((ClutterActor*)(a))->flags |= (f))

Sets the given flags on a ClutterActor

CLUTTER_ACTOR_UNSET_FLAGS()

#define CLUTTER_ACTOR_UNSET_FLAGS(a,f)  (((ClutterActor*)(a))->flags &= ~(f))

Unsets the given flags on a ClutterActor

CLUTTER_ACTOR_IS_MAPPED()

#define CLUTTER_ACTOR_IS_MAPPED(a)      ((((ClutterActor*)(a))->flags & CLUTTER_ACTOR_MAPPED) != FALSE)

Evaluates to TRUE if the CLUTTER_ACTOR_MAPPED flag is set.

Means "the actor will be painted if the stage is mapped."

TRUE if the actor is visible; and all parents with possible exception of the stage are visible; and an ancestor of the actor is a toplevel.

Clutter auto-maintains the mapped flag whenever actors are reparented or shown/hidden.

Since 0.2

CLUTTER_ACTOR_IS_REALIZED()

#define CLUTTER_ACTOR_IS_REALIZED(a)    ((((ClutterActor*)(a))->flags & CLUTTER_ACTOR_REALIZED) != FALSE)

Evaluates to TRUE if the CLUTTER_ACTOR_REALIZED flag is set.

The realized state has an actor-dependant interpretation. If an actor wants to delay allocating resources until it is attached to a stage, it may use the realize state to do so. However it is perfectly acceptable for an actor to allocate Cogl resources before being realized because there is only one GL context used by Clutter so any resources will work on any stage. If an actor is mapped it must also be realized, but an actor can be realized and unmapped (this is so hiding an actor temporarily doesn't do an expensive unrealize/realize).

To be realized an actor must be inside a stage, and all its parents must be realized.

Since 0.2

CLUTTER_ACTOR_IS_VISIBLE()

#define CLUTTER_ACTOR_IS_VISIBLE(a)     ((((ClutterActor*)(a))->flags & CLUTTER_ACTOR_VISIBLE) != FALSE)

Evaluates to TRUE if the actor has been shown, FALSE if it's hidden. Equivalent to the ClutterActor::visible object property.

Note that an actor is only painted onscreen if it's mapped, which means it's visible, and all its parents are visible, and one of the parents is a toplevel stage.

Since 0.2

CLUTTER_ACTOR_IS_REACTIVE()

#define CLUTTER_ACTOR_IS_REACTIVE(a)    ((((ClutterActor*)(a))->flags & CLUTTER_ACTOR_REACTIVE) != FALSE)

Evaluates to TRUE if the CLUTTER_ACTOR_REACTIVE flag is set.

Only reactive actors will receive event-related signals.

Since 0.6

enum ClutterActorFlags

typedef enum
{
  CLUTTER_ACTOR_MAPPED    = 1 << 1,
  CLUTTER_ACTOR_REALIZED  = 1 << 2,
  CLUTTER_ACTOR_REACTIVE  = 1 << 3,
  CLUTTER_ACTOR_VISIBLE   = 1 << 4,
  CLUTTER_ACTOR_NO_LAYOUT = 1 << 5
} ClutterActorFlags;

Flags used to signal the state of an actor.

enum ClutterRequestMode

typedef enum {
  CLUTTER_REQUEST_HEIGHT_FOR_WIDTH,
  CLUTTER_REQUEST_WIDTH_FOR_HEIGHT
} ClutterRequestMode;

Specifies the type of requests for a ClutterActor.

Since 0.8

struct ClutterGeometry

struct ClutterGeometry {
  gint   x;
  gint   y;
  guint  width;
  guint  height;
};

The rectangle containing an actor's bounding box, measured in pixels.

CLUTTER_CALLBACK()

#define CLUTTER_CALLBACK(f)        ((ClutterCallback) (f))

Convenience macro to cast a function to ClutterCallback

ClutterCallback ()

void                (*ClutterCallback)                  (ClutterActor *actor,
                                                         gpointer data);

Generic callback

ClutterActor

typedef struct {
  guint32 flags;
} ClutterActor;

Base class for actors.

struct ClutterActorClass

struct ClutterActorClass {
  void (* show)                 (ClutterActor          *actor);
  void (* show_all)             (ClutterActor          *actor);
  void (* hide)                 (ClutterActor          *actor);
  void (* hide_all)             (ClutterActor          *actor);
  void (* realize)              (ClutterActor          *actor);
  void (* unrealize)            (ClutterActor          *actor);
  void (* map)                  (ClutterActor          *actor);
  void (* unmap)                (ClutterActor          *actor);
  void (* paint)                (ClutterActor          *actor);
  void (* parent_set)           (ClutterActor          *actor,
                                 ClutterActor          *old_parent);

  void (* destroy)              (ClutterActor          *actor);
  void (* pick)                 (ClutterActor          *actor,
                                 const ClutterColor    *color);

  void (* queue_redraw)         (ClutterActor          *actor,
                                 ClutterActor          *leaf_that_queued);

  /* size negotiation */
  void (* get_preferred_width)  (ClutterActor           *actor,
                                 gfloat                  for_height,
                                 gfloat                 *min_width_p,
                                 gfloat                 *natural_width_p);
  void (* get_preferred_height) (ClutterActor           *actor,
                                 gfloat                  for_width,
                                 gfloat                 *min_height_p,
                                 gfloat                 *natural_height_p);
  void (* allocate)             (ClutterActor           *actor,
                                 const ClutterActorBox  *box,
                                 ClutterAllocationFlags  flags);

  /* transformations */
  void (* apply_transform)      (ClutterActor           *actor,
                                 CoglMatrix             *matrix);

  /* event signals */
  gboolean (* event)                (ClutterActor         *actor,
                                     ClutterEvent         *event);
  gboolean (* button_press_event)   (ClutterActor         *actor,
                                     ClutterButtonEvent   *event);
  gboolean (* button_release_event) (ClutterActor         *actor,
                                     ClutterButtonEvent   *event);
  gboolean (* scroll_event)         (ClutterActor         *actor,
                                     ClutterScrollEvent   *event);
  gboolean (* key_press_event)      (ClutterActor         *actor,
                                     ClutterKeyEvent      *event);
  gboolean (* key_release_event)    (ClutterActor         *actor,
                                     ClutterKeyEvent      *event);
  gboolean (* motion_event)         (ClutterActor         *actor,
                                     ClutterMotionEvent   *event);
  gboolean (* enter_event)          (ClutterActor         *actor,
                                     ClutterCrossingEvent *event);
  gboolean (* leave_event)          (ClutterActor         *actor,
                                     ClutterCrossingEvent *event);
  gboolean (* captured_event)       (ClutterActor         *actor,
                                     ClutterEvent         *event);
  void     (* key_focus_in)         (ClutterActor         *actor);
  void     (* key_focus_out)        (ClutterActor         *actor);

  void     (* queue_relayout)       (ClutterActor         *actor);
};

Base class for actors.

clutter_actor_set_flags ()

void                clutter_actor_set_flags             (ClutterActor *self,
                                                         ClutterActorFlags flags);

Sets flags on self

This function will emit notifications for the changed properties

Since 1.0

clutter_actor_unset_flags ()

void                clutter_actor_unset_flags           (ClutterActor *self,
                                                         ClutterActorFlags flags);

Unsets flags on self

This function will emit notifications for the changed properties

Since 1.0

clutter_actor_get_flags ()

ClutterActorFlags   clutter_actor_get_flags             (ClutterActor *self);

Retrieves the flags set on self

Since 1.0

clutter_actor_show ()

void                clutter_actor_show                  (ClutterActor *self);

Flags an actor to be displayed. An actor that isn't shown will not be rendered on the stage.

Actors are visible by default.

If this function is called on an actor without a parent, the "show-on-set-parent" will be set to TRUE as a side effect.

clutter_actor_show_all ()

void                clutter_actor_show_all              (ClutterActor *self);

Calls clutter_actor_show() on all children of an actor (if any).

Since 0.2

clutter_actor_hide ()

void                clutter_actor_hide                  (ClutterActor *self);

Flags an actor to be hidden. A hidden actor will not be rendered on the stage.

Actors are visible by default.

If this function is called on an actor without a parent, the "show-on-set-parent" property will be set to FALSE as a side-effect.

clutter_actor_hide_all ()

void                clutter_actor_hide_all              (ClutterActor *self);

Calls clutter_actor_hide() on all child actors (if any).

Since 0.2

clutter_actor_realize ()

void                clutter_actor_realize               (ClutterActor *self);

Realization informs the actor that it is attached to a stage. It can use this to allocate resources if it wanted to delay allocation until it would be rendered. However it is perfectly acceptable for an actor to create resources before being realized because Clutter only ever has a single rendering context so that actor is free to be moved from one stage to another.

This function does nothing if the actor is already realized.

Because a realized actor must have realized parent actors, calling clutter_actor_realize() will also realize all parents of the actor.

This function does not realize child actors, except in the special case that realizing the stage, when the stage is visible, will suddenly map (and thus realize) the children of the stage.

clutter_actor_unrealize ()

void                clutter_actor_unrealize             (ClutterActor *self);

Unrealization informs the actor that it may be being destroyed or moved to another stage. The actor may want to destroy any underlying graphics resources at this point. However it is perfectly acceptable for it to retain the resources until the actor is destroyed because Clutter only ever uses a single rendering context and all of the graphics resources are valid on any stage.

Because mapped actors must be realized, actors may not be unrealized if they are mapped. This function hides the actor to be sure it isn't mapped, an application-visible side effect that you may not be expecting.

This function should not really be in the public API, because there isn't a good reason to call it. ClutterActor will already unrealize things for you when it's important to do so.

If you were using clutter_actor_unrealize() in a dispose implementation, then don't, just chain up to ClutterActor's dispose.

If you were using clutter_actor_unrealize() to implement unrealizing children of your container, then don't, ClutterActor will already take care of that.

If you were using clutter_actor_unrealize() to re-realize to create your resources in a different way, then use _clutter_actor_rerealize() (inside Clutter) or just call your code that recreates your resources directly (outside Clutter).

clutter_actor_paint ()

void                clutter_actor_paint                 (ClutterActor *self);

Renders the actor to display.

This function should not be called directly by applications. Call clutter_actor_queue_redraw() to queue paints, instead.

This function will emit the "paint" signal.

clutter_actor_queue_redraw ()

void                clutter_actor_queue_redraw          (ClutterActor *self);

Queues up a redraw of an actor and any children. The redraw occurs once the main loop becomes idle (after the current batch of events has been processed, roughly).

Applications rarely need to call this, as redraws are handled automatically by modification functions.

This function will not do anything if self is not visible, or if the actor is inside an invisible part of the scenegraph.

Also be aware that painting is a NOP for actors with an opacity of 0

clutter_actor_queue_relayout ()

void                clutter_actor_queue_relayout        (ClutterActor *self);

Indicates that the actor's size request or other layout-affecting properties may have changed. This function is used inside ClutterActor subclass implementations, not by applications directly.

Queueing a new layout automatically queues a redraw as well.

Since 0.8

clutter_actor_destroy ()

void                clutter_actor_destroy               (ClutterActor *self);

Destroys an actor. When an actor is destroyed, it will break any references it holds to other objects. If the actor is inside a container, the actor will be removed.

When you destroy a container, its children will be destroyed as well.

Note: you cannot destroy the ClutterStage returned by clutter_stage_get_default().

clutter_actor_event ()

gboolean            clutter_actor_event                 (ClutterActor *actor,
                                                         ClutterEvent *event,
                                                         gboolean capture);

This function is used to emit an event on the main stage. You should rarely need to use this function, except for synthetising events.

Since 0.6

clutter_actor_should_pick_paint ()

gboolean            clutter_actor_should_pick_paint     (ClutterActor *self);

Should be called inside the implementation of the "pick" virtual function in order to check whether the actor should paint itself in pick mode or not.

This function should never be called directly by applications.

clutter_actor_map ()

void                clutter_actor_map                   (ClutterActor *self);

Sets the CLUTTER_ACTOR_MAPPED flag on the actor and possibly maps and realizes its children if they are visible. Does nothing if the actor is not visible.

Calling this is allowed in only one case: you are implementing the "map" virtual function in an actor and you need to map the children of that actor. It is not necessary to call this if you implement ClutterContainer because the default implementation will automatically map children of containers.

When overriding map, it is mandatory to chain up to the parent implementation.

Since 1.0

clutter_actor_unmap ()

void                clutter_actor_unmap                 (ClutterActor *self);

Unsets the CLUTTER_ACTOR_MAPPED flag on the actor and possibly unmaps its children if they were mapped.

Calling this is allowed in only one case: you are implementing the "unmap" virtual function in an actor and you need to unmap the children of that actor. It is not necessary to call this if you implement ClutterContainer because the default implementation will automatically unmap children of containers.

When overriding unmap, it is mandatory to chain up to the parent implementation.

Since 1.0

enum ClutterAllocationFlags

typedef enum
{
  CLUTTER_ALLOCATION_NONE         = 0,
  CLUTTER_ABSOLUTE_ORIGIN_CHANGED = 1 << 1
} ClutterAllocationFlags;

Flags passed to the ClutterActor::allocate() virtual function and to the clutter_actor_allocate() function

Since 1.0

clutter_actor_allocate ()

void                clutter_actor_allocate              (ClutterActor *self,
                                                         const ClutterActorBox *box,
                                                         ClutterAllocationFlags flags);

Called by the parent of an actor to assign the actor its size. Should never be called by applications (except when implementing a container or layout manager).

Actors can know from their allocation box whether they have moved with respect to their parent actor. The flags parameter describes additional information about the allocation, for instance whether the parent has moved with respect to the stage, for example because a grandparent's origin has moved.

Since 0.8

clutter_actor_allocate_preferred_size ()

void                clutter_actor_allocate_preferred_size
                                                        (ClutterActor *self,
                                                         ClutterAllocationFlags flags);

Allocates the natural size of self.

This function is a utility call for ClutterActor implementations that allocates the actor's preferred natural size. It can be used by fixed layout managers (like ClutterGroup or so called 'composite actors') inside the ClutterActor::allocate implementation to give each child exactly how much space it requires.

This function is not meant to be used by applications. It is also not meant to be used outside the implementation of the ClutterActor::allocate virtual function.

Since 0.8

clutter_actor_allocate_available_size ()

void                clutter_actor_allocate_available_size
                                                        (ClutterActor *self,
                                                         gfloat x,
                                                         gfloat y,
                                                         gfloat available_width,
                                                         gfloat available_height,
                                                         ClutterAllocationFlags flags);

Allocates self taking into account the ClutterActor's preferred size, but limiting it to the maximum available width and height provided.

This function will do the right thing when dealing with the actor's request mode.

The implementation of this function is equivalent to:

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if (request_mode == CLUTTER_REQUEST_HEIGHT_FOR_WIDTH)
  {
    clutter_actor_get_preferred_width (self, available_height,
                                       &min_width,
                                       &natural_width);
    width = CLAMP (natural_width, min_width, available_width);

    clutter_actor_get_preferred_height (self, width,
                                        &min_height,
                                        &natural_height);
    height = CLAMP (natural_height, min_height, available_height);
  }
else
  {
    clutter_actor_get_preferred_height (self, available_width,
                                        &min_height,
                                        &natural_height);
    height = CLAMP (natural_height, min_height, available_height);

    clutter_actor_get_preferred_width (self, height,
                                       &min_width,
                                       &natural_width);
    width = CLAMP (natural_width, min_width, available_width);
  }

box.x1 = x; box.y1 = y;
box.x2 = box.x1 + available_width;
box.y2 = box.y1 + available_height;
clutter_actor_allocate (self, &box, flags);

This function can be used by fluid layout managers to allocate an actor's preferred size without making it bigger than the area available for the container.

Since 1.0

clutter_actor_get_allocation_box ()

void                clutter_actor_get_allocation_box    (ClutterActor *self,
                                                         ClutterActorBox *box);

Gets the layout box an actor has been assigned. The allocation can only be assumed valid inside a paint() method; anywhere else, it may be out-of-date.

An allocation does not incorporate the actor's scale or anchor point; those transformations do not affect layout, only rendering.

Since 0.8

clutter_actor_get_allocation_geometry ()

void                clutter_actor_get_allocation_geometry
                                                        (ClutterActor *self,
                                                         ClutterGeometry *geom);

Gets the layout box an actor has been assigned. The allocation can only be assumed valid inside a paint() method; anywhere else, it may be out-of-date.

An allocation does not incorporate the actor's scale or anchor point; those transformations do not affect layout, only rendering.

The returned rectangle is in pixels.

Since 0.8

clutter_actor_get_allocation_vertices ()

void                clutter_actor_get_allocation_vertices
                                                        (ClutterActor *self,
                                                         ClutterActor *ancestor,
                                                         ClutterVertex verts[]);

Calculates the transformed coordinates of the four corners of the actor in the plane of ancestor. The returned vertices relate to the ClutterActorBox coordinates as follows:

If ancestor is NULL the ancestor will be the ClutterStage. In this case, the coordinates returned will be the coordinates on the stage before the projection is applied. This is different from the behaviour of clutter_actor_get_abs_allocation_vertices().

Since 0.6

clutter_actor_get_preferred_size ()

void                clutter_actor_get_preferred_size    (ClutterActor *self,
                                                         gfloat *min_width_p,
                                                         gfloat *min_height_p,
                                                         gfloat *natural_width_p,
                                                         gfloat *natural_height_p);

Computes the preferred minimum and natural size of an actor, taking into account the actor's geometry management (either height-for-width or width-for-height).

The width and height used to compute the preferred height and preferred width are the actor's natural ones.

If you need to control the height for the preferred width, or the width for the preferred height, you should use clutter_actor_get_preferred_width() and clutter_actor_get_preferred_height(), and check the actor's preferred geometry management using the "request-mode" property.

Since 0.8

clutter_actor_get_preferred_width ()

void                clutter_actor_get_preferred_width   (ClutterActor *self,
                                                         gfloat for_height,
                                                         gfloat *min_width_p,
                                                         gfloat *natural_width_p);

Computes the requested minimum and natural widths for an actor, optionally depending on the specified height, or if they are already computed, returns the cached values.

An actor may not get its request - depending on the layout manager that's in effect.

A request should not incorporate the actor's scale or anchor point; those transformations do not affect layout, only rendering.

Since 0.8

clutter_actor_get_preferred_height ()

void                clutter_actor_get_preferred_height  (ClutterActor *self,
                                                         gfloat for_width,
                                                         gfloat *min_height_p,
                                                         gfloat *natural_height_p);

Computes the requested minimum and natural heights for an actor, or if they are already computed, returns the cached values.

An actor may not get its request - depending on the layout manager that's in effect.

A request should not incorporate the actor's scale or anchor point; those transformations do not affect layout, only rendering.

Since 0.8

clutter_actor_set_fixed_position_set ()

void                clutter_actor_set_fixed_position_set
                                                        (ClutterActor *self,
                                                         gboolean is_set);

Sets whether an actor has a fixed position set (and will thus be unaffected by any layout manager).

Since 0.8

clutter_actor_get_fixed_position_set ()

gboolean            clutter_actor_get_fixed_position_set
                                                        (ClutterActor *self);

Checks whether an actor has a fixed position set (and will thus be unaffected by any layout manager).

Since 0.8

clutter_actor_set_request_mode ()

void                clutter_actor_set_request_mode      (ClutterActor *self,
                                                         ClutterRequestMode mode);

Sets the geometry request mode of self.

The mode determines the order for invoking clutter_actor_get_preferred_width() and clutter_actor_get_preferred_height()

Since 1.2

clutter_actor_get_request_mode ()

ClutterRequestMode  clutter_actor_get_request_mode      (ClutterActor *self);

Retrieves the geometry request mode of self

Since 1.2

clutter_actor_set_geometry ()

void                clutter_actor_set_geometry          (ClutterActor *self,
                                                         const ClutterGeometry *geometry);

Sets the actor's fixed position and forces its minimum and natural size, in pixels. This means the untransformed actor will have the given geometry. This is the same as calling clutter_actor_set_position() and clutter_actor_set_size().

clutter_actor_get_geometry ()

void                clutter_actor_get_geometry          (ClutterActor *self,
                                                         ClutterGeometry *geometry);

Gets the size and position of an actor relative to its parent actor. This is the same as calling clutter_actor_get_position() and clutter_actor_get_size(). It tries to "do what you mean" and get the requested size and position if the actor's allocation is invalid.

clutter_actor_set_size ()

void                clutter_actor_set_size              (ClutterActor *self,
                                                         gfloat width,
                                                         gfloat height);

Sets the actor's size request in pixels. This overrides any "normal" size request the actor would have. For example a text actor might normally request the size of the text; this function would force a specific size instead.

If width and/or height are -1 the actor will use its "normal" size request instead of overriding it, i.e. you can "unset" the size with -1.

This function sets or unsets both the minimum and natural size.

clutter_actor_get_size ()

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

This function tries to "do what you mean" and return the size an actor will have. If the actor has a valid allocation, the allocation will be returned; otherwise, the actors natural size request will be returned.

If you care whether you get the request vs. the allocation, you should probably call a different function like clutter_actor_get_allocation_box() or clutter_actor_get_preferred_width().

Since 0.2

clutter_actor_set_position ()

void                clutter_actor_set_position          (ClutterActor *self,
                                                         gfloat x,
                                                         gfloat y);

Sets the actor's fixed position in pixels relative to any parent actor.

If a layout manager is in use, this position will override the layout manager and force a fixed position.

clutter_actor_get_position ()

void                clutter_actor_get_position          (ClutterActor *self,
                                                         gfloat *x,
                                                         gfloat *y);

This function tries to "do what you mean" and tell you where the actor is, prior to any transformations. Retrieves the fixed position of an actor in pixels, if one has been set; otherwise, if the allocation is valid, returns the actor's allocated position; otherwise, returns 0,0.

The returned position is in pixels.

Since 0.6

clutter_actor_set_width ()

void                clutter_actor_set_width             (ClutterActor *self,
                                                         gfloat width);

Forces a width on an actor, causing the actor's preferred width and height (if any) to be ignored.

If width is -1 the actor will use its preferred width request instead of overriding it, i.e. you can "unset" the width with -1.

This function sets both the minimum and natural size of the actor.

Since 0.2

clutter_actor_get_width ()

gfloat              clutter_actor_get_width             (ClutterActor *self);

Retrieves the width of a ClutterActor.

If the actor has a valid allocation, this function will return the width of the allocated area given to the actor.

If the actor does not have a valid allocation, this function will return the actor's natural width, that is the preferred width of the actor.

If you care whether you get the preferred width or the width that has been assigned to the actor, you should probably call a different function like clutter_actor_get_allocation_box() to retrieve the allocated size or clutter_actor_get_preferred_width() to retrieve the preferred width.

If an actor has a fixed width, for instance a width that has been assigned using clutter_actor_set_width(), the width returned will be the same value.

clutter_actor_set_height ()

void                clutter_actor_set_height            (ClutterActor *self,
                                                         gfloat height);

Forces a height on an actor, causing the actor's preferred width and height (if any) to be ignored.

If height is -1 the actor will use its preferred height instead of overriding it, i.e. you can "unset" the height with -1.

This function sets both the minimum and natural size of the actor.

Since 0.2

clutter_actor_get_height ()

gfloat              clutter_actor_get_height            (ClutterActor *self);

Retrieves the height of a ClutterActor.

If the actor has a valid allocation, this function will return the height of the allocated area given to the actor.

If the actor does not have a valid allocation, this function will return the actor's natural height, that is the preferred height of the actor.

If you care whether you get the preferred height or the height that has been assigned to the actor, you should probably call a different function like clutter_actor_get_allocation_box() to retrieve the allocated size or clutter_actor_get_preferred_height() to retrieve the preferred height.

If an actor has a fixed height, for instance a height that has been assigned using clutter_actor_set_height(), the height returned will be the same value.

clutter_actor_set_x ()

void                clutter_actor_set_x                 (ClutterActor *self,
                                                         gfloat x);

Sets the actor's X coordinate, relative to its parent, in pixels.

Overrides any layout manager and forces a fixed position for the actor.

Since 0.6

clutter_actor_get_x ()

gfloat              clutter_actor_get_x                 (ClutterActor *self);

Retrieves the X coordinate of a ClutterActor.

This function tries to "do what you mean", by returning the correct value depending on the actor's state.

If the actor has a valid allocation, this function will return the X coordinate of the origin of the allocation box.

If the actor has any fixed coordinate set using clutter_actor_set_x(), clutter_actor_set_position() or clutter_actor_set_geometry(), this function will return that coordinate.

If both the allocation and a fixed position are missing, this function will return 0.

clutter_actor_set_y ()

void                clutter_actor_set_y                 (ClutterActor *self,
                                                         gfloat y);

Sets the actor's Y coordinate, relative to its parent, in pixels.#

Overrides any layout manager and forces a fixed position for the actor.

Since 0.6

clutter_actor_get_y ()

gfloat              clutter_actor_get_y                 (ClutterActor *self);

Retrieves the Y coordinate of a ClutterActor.

This function tries to "do what you mean", by returning the correct value depending on the actor's state.

If the actor has a valid allocation, this function will return the Y coordinate of the origin of the allocation box.

If the actor has any fixed coordinate set using clutter_actor_set_y(), clutter_actor_set_position() or clutter_actor_set_geometry(), this function will return that coordinate.

If both the allocation and a fixed position are missing, this function will return 0.

clutter_actor_move_by ()

void                clutter_actor_move_by               (ClutterActor *self,
                                                         gfloat dx,
                                                         gfloat dy);

Moves an actor by the specified distance relative to its current position in pixels.

This function modifies the fixed position of an actor and thus removes it from any layout management. Another way to move an actor is with an anchor point, see clutter_actor_set_anchor_point().

Since 0.2

clutter_actor_set_rotation ()

void                clutter_actor_set_rotation          (ClutterActor *self,
                                                         ClutterRotateAxis axis,
                                                         gdouble angle,
                                                         gfloat x,
                                                         gfloat y,
                                                         gfloat z);

Sets the rotation angle of self around the given axis.

The rotation center coordinates used depend on the value of axis:

The rotation coordinates are relative to the anchor point of the actor, set using clutter_actor_set_anchor_point(). If no anchor point is set, the upper left corner is assumed as the origin.

Since 0.8

clutter_actor_set_z_rotation_from_gravity ()

void                clutter_actor_set_z_rotation_from_gravity
                                                        (ClutterActor *self,
                                                         gdouble angle,
                                                         ClutterGravity gravity);

Sets the rotation angle of self around the Z axis using the center point specified as a compass point. For example to rotate such that the center of the actor remains static you can use CLUTTER_GRAVITY_CENTER. If the actor changes size the center point will move accordingly.

Since 1.0

clutter_actor_get_rotation ()

gdouble             clutter_actor_get_rotation          (ClutterActor *self,
                                                         ClutterRotateAxis axis,
                                                         gfloat *x,
                                                         gfloat *y,
                                                         gfloat *z);

Retrieves the angle and center of rotation on the given axis, set using clutter_actor_set_rotation().

Since 0.8

clutter_actor_get_z_rotation_gravity ()

ClutterGravity      clutter_actor_get_z_rotation_gravity
                                                        (ClutterActor *self);

Retrieves the center for the rotation around the Z axis as a compass direction. If the center was specified in pixels or units this will return CLUTTER_GRAVITY_NONE.

Since 1.0

clutter_actor_is_rotated ()

gboolean            clutter_actor_is_rotated            (ClutterActor *self);

Checks whether any rotation is applied to the actor.

Since 0.6

clutter_actor_set_opacity ()

void                clutter_actor_set_opacity           (ClutterActor *self,
                                                         guint8 opacity);

Sets the actor's opacity, with zero being completely transparent and 255 (0xff) being fully opaque.

clutter_actor_get_opacity ()

guint8              clutter_actor_get_opacity           (ClutterActor *self);

Retrieves the opacity value of an actor, as set by clutter_actor_set_opacity().

For retrieving the absolute opacity of the actor inside a paint virtual function, see clutter_actor_get_paint_opacity().

clutter_actor_set_name ()

void                clutter_actor_set_name              (ClutterActor *self,
                                                         const gchar *name);

Sets the given name to self. The name can be used to identify a ClutterActor.

clutter_actor_get_name ()

const gchar *       clutter_actor_get_name              (ClutterActor *self);

Retrieves the name of self.

clutter_actor_get_gid ()

guint32             clutter_actor_get_gid               (ClutterActor *self);

Retrieves the unique id for self.

Since 0.6

clutter_actor_set_clip ()

void                clutter_actor_set_clip              (ClutterActor *self,
                                                         gfloat xoff,
                                                         gfloat yoff,
                                                         gfloat width,
                                                         gfloat height);

Sets clip area for self. The clip area is always computed from the upper left corner of the actor, even if the anchor point is set otherwise.

Since 0.6

clutter_actor_remove_clip ()

void                clutter_actor_remove_clip           (ClutterActor *self);

Removes clip area from self.

clutter_actor_has_clip ()

gboolean            clutter_actor_has_clip              (ClutterActor *self);

Determines whether the actor has a clip area set or not.

Since 0.1.1

clutter_actor_get_clip ()

void                clutter_actor_get_clip              (ClutterActor *self,
                                                         gfloat *xoff,
                                                         gfloat *yoff,
                                                         gfloat *width,
                                                         gfloat *height);

Gets the clip area for self, if any is set

Since 0.6

clutter_actor_set_parent ()

void                clutter_actor_set_parent            (ClutterActor *self,
                                                         ClutterActor *parent);

Sets the parent of self to parent. The opposite function is clutter_actor_unparent().

This function should not be used by applications, but by custom container actor subclasses.

clutter_actor_get_parent ()

ClutterActor *         clutter_actor_get_parent         (ClutterActor *self);

Retrieves the parent of self.

clutter_actor_reparent ()

void                clutter_actor_reparent              (ClutterActor *self,
                                                         ClutterActor *new_parent);

This function resets the parent actor of self. It is logically equivalent to calling clutter_actor_unparent() and clutter_actor_set_parent(), but more efficiently implemented, ensures the child is not finalized when unparented, and emits the parent-set signal only one time.

Since 0.2

clutter_actor_unparent ()

void                clutter_actor_unparent              (ClutterActor *self);

Removes the parent of self.

This function should not be used in applications. It should be called by implementations of container actors, to dissociate a child from the container.

Since 0.1.1

clutter_actor_raise ()

void                clutter_actor_raise                 (ClutterActor *self,
                                                         ClutterActor *below);

Puts self above below.

Both actors must have the same parent, and the parent must implement the ClutterContainer interface

This function is the equivalent of clutter_container_raise_child().

clutter_actor_lower ()

void                clutter_actor_lower                 (ClutterActor *self,
                                                         ClutterActor *above);

Puts self below above.

Both actors must have the same parent, and the parent must implement the ClutterContainer interface.

This function is the equivalent of clutter_container_lower_child().

clutter_actor_raise_top ()

void                clutter_actor_raise_top             (ClutterActor *self);

Raises self to the top.

This function calls clutter_actor_raise() internally.

clutter_actor_lower_bottom ()

void                clutter_actor_lower_bottom          (ClutterActor *self);

Lowers self to the bottom.

This function calls clutter_actor_lower() internally.

clutter_actor_get_stage ()

ClutterActor *          clutter_actor_get_stage         (ClutterActor *actor);

Retrieves the ClutterStage where actor is contained.

Since 0.8

clutter_actor_push_internal ()

void                clutter_actor_push_internal         (ClutterActor *self);

Should be used by actors implementing the ClutterContainer and with internal children added through clutter_actor_set_parent(), for instance:

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static void
my_actor_init (MyActor *self)
{
  self->priv = SELF_ACTOR_GET_PRIVATE (self);

  clutter_actor_push_internal (CLUTTER_ACTOR (self));

  /* calling clutter_actor_set_parent() now will result in
   * the internal flag being set on a child of MyActor
   */

  /* internal child: a background texture */
  self->priv->background_tex = clutter_texture_new ();
  clutter_actor_set_parent (self->priv->background_tex,
                            CLUTTER_ACTOR (self));

  /* internal child: a label */
  self->priv->label = clutter_text_new ();
  clutter_actor_set_parent (self->priv->label,
                            CLUTTER_ACTOR (self));

  clutter_actor_pop_internal (CLUTTER_ACTOR (self));

  /* calling clutter_actor_set_parent() now will not result in
   * the internal flag being set on a child of MyActor
   */
}

This function will be used by Clutter to toggle an "internal child" flag whenever clutter_actor_set_parent() is called; internal children are handled differently by Clutter, specifically when destroying their parent.

Call clutter_actor_pop_internal() when you finished adding internal children.

Nested calls to clutter_actor_push_internal() are allowed, but each one must by followed by a clutter_actor_pop_internal() call.

Since 1.2

clutter_actor_pop_internal ()

void                clutter_actor_pop_internal          (ClutterActor *self);

Disables the effects of clutter_actor_pop_internal()

Since 1.2

clutter_actor_set_depth ()

void                clutter_actor_set_depth             (ClutterActor *self,
                                                         gfloat depth);

Sets the Z coordinate of self to depth.

The unit used by depth is dependant on the perspective setup. See also clutter_stage_set_perspective().

clutter_actor_get_depth ()

gfloat              clutter_actor_get_depth             (ClutterActor *self);

Retrieves the depth of self.

clutter_actor_set_scale ()

void                clutter_actor_set_scale             (ClutterActor *self,
                                                         gdouble scale_x,
                                                         gdouble scale_y);

Scales an actor with the given factors. The scaling is relative to the scale center and the anchor point. The scale center is unchanged by this function and defaults to 0,0.

Since 0.2

clutter_actor_set_scale_full ()

void                clutter_actor_set_scale_full        (ClutterActor *self,
                                                         gdouble scale_x,
                                                         gdouble scale_y,
                                                         gfloat center_x,
                                                         gfloat center_y);

Scales an actor with the given factors around the given center point. The center point is specified in pixels relative to the anchor point (usually the top left corner of the actor).

Since 1.0

clutter_actor_set_scale_with_gravity ()

void                clutter_actor_set_scale_with_gravity
                                                        (ClutterActor *self,
                                                         gdouble scale_x,
                                                         gdouble scale_y,
                                                         ClutterGravity gravity);

Scales an actor with the given factors around the given center point. The center point is specified as one of the compass directions in ClutterGravity. For example, setting it to north will cause the top of the actor to remain unchanged and the rest of the actor to expand left, right and downwards.

Since 1.0

clutter_actor_get_scale ()

void                clutter_actor_get_scale             (ClutterActor *self,
                                                         gdouble *scale_x,
                                                         gdouble *scale_y);

Retrieves an actors scale factors.

Since 0.2

clutter_actor_get_scale_center ()

void                clutter_actor_get_scale_center      (ClutterActor *self,
                                                         gfloat *center_x,
                                                         gfloat *center_y);

Retrieves the scale center coordinate in pixels relative to the top left corner of the actor. If the scale center was specified using a ClutterGravity this will calculate the pixel offset using the current size of the actor.

Since 1.0

clutter_actor_get_scale_gravity ()

ClutterGravity      clutter_actor_get_scale_gravity     (ClutterActor *self);

Retrieves the scale center as a compass direction. If the scale center was specified in pixels or units this will return CLUTTER_GRAVITY_NONE.

Since 1.0

clutter_actor_is_scaled ()

gboolean            clutter_actor_is_scaled             (ClutterActor *self);

Checks whether the actor is scaled in either dimension.

Since 0.6

clutter_actor_apply_transform_to_point ()

void                clutter_actor_apply_transform_to_point
                                                        (ClutterActor *self,
                                                         const ClutterVertex *point,
                                                         ClutterVertex *vertex);

Transforms point in coordinates relative to the actor into screen-relative coordinates with the current actor transformation (i.e. scale, rotation, etc)

Since 0.4

clutter_actor_transform_stage_point ()

gboolean            clutter_actor_transform_stage_point (ClutterActor *self,
                                                         gfloat x,
                                                         gfloat y,
                                                         gfloat *x_out,
                                                         gfloat *y_out);

This function translates screen coordinates (x, y) to coordinates relative to the actor. For example, it can be used to translate screen events from global screen coordinates into actor-local coordinates.

The conversion can fail, notably if the transform stack results in the actor being projected on the screen as a mere line.

The conversion should not be expected to be pixel-perfect due to the nature of the operation. In general the error grows when the skewing of the actor rectangle on screen increases.

Note: This function is fairly computationally intensive.

Note: This function only works when the allocation is up-to-date, i.e. inside of paint()

Since 0.6

clutter_actor_apply_relative_transform_to_point ()

void                clutter_actor_apply_relative_transform_to_point
                                                        (ClutterActor *self,
                                                         ClutterActor *ancestor,
                                                         const ClutterVertex *point,
                                                         ClutterVertex *vertex);

Transforms point in coordinates relative to the actor into ancestor-relative coordinates using the relevant transform stack (i.e. scale, rotation, etc).

If ancestor is NULL the ancestor will be the ClutterStage. In this case, the coordinates returned will be the coordinates on the stage before the projection is applied. This is different from the behaviour of clutter_actor_apply_transform_to_point().

Since 0.6

clutter_actor_get_transformed_position ()

void                clutter_actor_get_transformed_position
                                                        (ClutterActor *self,
                                                         gfloat *x,
                                                         gfloat *y);

Gets the absolute position of an actor, in pixels relative to the stage.

Since 0.8

clutter_actor_get_transformed_size ()

void                clutter_actor_get_transformed_size  (ClutterActor *self,
                                                         gfloat *width,
                                                         gfloat *height);

Gets the absolute size of an actor in pixels, taking into account the scaling factors.

If the actor has a valid allocation, the allocated size will be used. If the actor has not a valid allocation then the preferred size will be transformed and returned.

If you want the transformed allocation, see clutter_actor_get_abs_allocation_vertices() instead.

Since 0.8

clutter_actor_get_paint_opacity ()

guint8              clutter_actor_get_paint_opacity     (ClutterActor *self);

Retrieves the absolute opacity of the actor, as it appears on the stage.

This function traverses the hierarchy chain and composites the opacity of the actor with that of its parents.

This function is intended for subclasses to use in the paint virtual function, to paint themselves with the correct opacity.

Since 0.8

clutter_actor_get_paint_visibility ()

gboolean            clutter_actor_get_paint_visibility  (ClutterActor *self);

Retrieves the 'paint' visibility of an actor recursively checking for non visible parents.

This is by definition the same as CLUTTER_ACTOR_IS_MAPPED().

Since 0.8.4

clutter_actor_get_abs_allocation_vertices ()

void                clutter_actor_get_abs_allocation_vertices
                                                        (ClutterActor *self,
                                                         ClutterVertex verts[]);

Calculates the transformed screen coordinates of the four corners of the actor; the returned vertices relate to the ClutterActorBox coordinates as follows:

Since 0.4

clutter_actor_get_transformation_matrix ()

void                clutter_actor_get_transformation_matrix
                                                        (ClutterActor *self,
                                                         CoglMatrix *matrix);

Retrieves the transformations applied to self

Since 1.0

clutter_actor_set_anchor_point ()

void                clutter_actor_set_anchor_point      (ClutterActor *self,
                                                         gfloat anchor_x,
                                                         gfloat anchor_y);

Sets an anchor point for self. The anchor point is a point in the coordinate space of an actor to which the actor position within its parent is relative; the default is (0, 0), i.e. the top-left corner of the actor.

Since 0.6

clutter_actor_get_anchor_point ()

void                clutter_actor_get_anchor_point      (ClutterActor *self,
                                                         gfloat *anchor_x,
                                                         gfloat *anchor_y);

Gets the current anchor point of the actor in pixels.

Since 0.6

clutter_actor_set_anchor_point_from_gravity ()

void                clutter_actor_set_anchor_point_from_gravity
                                                        (ClutterActor *self,
                                                         ClutterGravity gravity);

Sets an anchor point on the actor, based on the given gravity (this is a convenience function wrapping clutter_actor_set_anchor_point()).

Since version 1.0 the anchor point will be stored as a gravity so that if the actor changes size then the anchor point will move. For example, if you set the anchor point to CLUTTER_GRAVITY_SOUTH_EAST and later double the size of the actor, the anchor point will move to the bottom right.

Since 0.6

clutter_actor_get_anchor_point_gravity ()

ClutterGravity      clutter_actor_get_anchor_point_gravity
                                                        (ClutterActor *self);

Retrieves the anchor position expressed as a ClutterGravity. If the anchor point was specified using pixels or units this will return CLUTTER_GRAVITY_NONE.

Since 1.0

clutter_actor_move_anchor_point ()

void                clutter_actor_move_anchor_point     (ClutterActor *self,
                                                         gfloat anchor_x,
                                                         gfloat anchor_y);

Sets an anchor point for the actor, and adjusts the actor postion so that the relative position of the actor toward its parent remains the same.

Since 0.6

clutter_actor_move_anchor_point_from_gravity ()

void                clutter_actor_move_anchor_point_from_gravity
                                                        (ClutterActor *self,
                                                         ClutterGravity gravity);

Sets an anchor point on the actor based on the given gravity, adjusting the actor postion so that its relative position within its parent remains unchanged.

Since version 1.0 the anchor point will be stored as a gravity so that if the actor changes size then the anchor point will move. For example, if you set the anchor point to CLUTTER_GRAVITY_SOUTH_EAST and later double the size of the actor, the anchor point will move to the bottom right.

Since 0.6

clutter_actor_set_reactive ()

void                clutter_actor_set_reactive          (ClutterActor *actor,
                                                         gboolean reactive);

Sets actor as reactive. Reactive actors will receive events.

Since 0.6

clutter_actor_get_reactive ()

gboolean            clutter_actor_get_reactive          (ClutterActor *actor);

Checks whether actor is marked as reactive.

Since 0.6

clutter_actor_set_shader ()

gboolean            clutter_actor_set_shader            (ClutterActor *self,
                                                         ClutterShader *shader);

Sets the ClutterShader to be used when rendering self.

If shader is NULL it will unset any currently set shader for the actor.

Since 0.6

clutter_actor_get_shader ()

ClutterShader *        clutter_actor_get_shader         (ClutterActor *self);

Queries the currently set ClutterShader on self.

Since 0.6

clutter_actor_set_shader_param ()

void                clutter_actor_set_shader_param      (ClutterActor *self,
                                                         const gchar *param,
                                                         const GValue *value);

Sets the value for a named parameter of the shader applied to actor.

Since 1.0

clutter_actor_set_shader_param_float ()

void                clutter_actor_set_shader_param_float
                                                        (ClutterActor *self,
                                                         const gchar *param,
                                                         gfloat value);

Sets the value for a named float parameter of the shader applied to actor.

Since 0.8

clutter_actor_set_shader_param_int ()

void                clutter_actor_set_shader_param_int  (ClutterActor *self,
                                                         const gchar *param,
                                                         gint value);

Sets the value for a named int parameter of the shader applied to actor.

Since 0.8

clutter_actor_grab_key_focus ()

void                clutter_actor_grab_key_focus        (ClutterActor *self);

Sets the key focus of the ClutterStage including self to this ClutterActor.

Since 1.0

clutter_actor_get_pango_context ()

PangoContext *      clutter_actor_get_pango_context     (ClutterActor *self);

Retrieves the PangoContext for self. The actor's PangoContext is already configured using the appropriate font map, resolution and font options.

Unlike clutter_actor_create_pango_context(), this context is owend by the ClutterActor and it will be updated each time the options stored by the ClutterBackend change.

You can use the returned PangoContext to create a PangoLayout and render text using cogl_pango_render_layout() to reuse the glyphs cache also used by Clutter.

Since 1.0

clutter_actor_create_pango_context ()

PangoContext *      clutter_actor_create_pango_context  (ClutterActor *self);

Creates a PangoContext for the given actor. The PangoContext is already configured using the appropriate font map, resolution and font options.

See also clutter_actor_get_pango_context().

Since 1.0

clutter_actor_create_pango_layout ()

PangoLayout *       clutter_actor_create_pango_layout   (ClutterActor *self,
                                                         const gchar *text);

Creates a new PangoLayout from the same PangoContext used by the ClutterActor. The PangoLayout is already configured with the font map, resolution and font options, and the given text.

If you want to keep around a PangoLayout created by this function you will have to connect to the "font-changed" and "resolution-changed" signals, and call pango_layout_context_changed() in response to them.

Since 1.0

clutter_actor_is_in_clone_paint ()

gboolean            clutter_actor_is_in_clone_paint     (ClutterActor *self);

Checks whether self is being currently painted by a ClutterClone

This function is useful only inside the ::paint virtual function implementations or within handlers for the "paint" signal

This function should not be used by applications

Since 1.0

clutter_actor_set_text_direction ()

void                clutter_actor_set_text_direction    (ClutterActor *self,
                                                         ClutterTextDirection text_dir);

Sets the ClutterTextDirection for an actor

The passed text direction must not be CLUTTER_TEXT_DIRECTION_DEFAULT

If self implements ClutterContainer then this function will recurse inside all the children of self (including the internal ones).

Composite actors not implementing ClutterContainer, or actors requiring special handling when the text direction changes, should connect to the "notify" signal for the "text-direction" property

Since 1.2

clutter_actor_get_text_direction ()

ClutterTextDirection  clutter_actor_get_text_direction  (ClutterActor *self);

Retrieves the value set using clutter_actor_set_text_direction()

If no text direction has been previously set, the default text direction, as returned by clutter_get_default_text_direction(), will be returned instead

Since 1.2

clutter_actor_has_pointer ()

gboolean            clutter_actor_has_pointer           (ClutterActor *self);

Checks whether an actor contains the the pointer of a ClutterInputDevice

Since 1.2

struct ClutterActorBox

struct ClutterActorBox {
  gfloat x1;
  gfloat y1;

  gfloat x2;
  gfloat y2;
};

Bounding box of an actor. The coordinates of the top left and right bottom corners of an actor. The coordinates of the two points are expressed in pixels with sub-pixel precision

clutter_actor_box_new ()

ClutterActorBox *   clutter_actor_box_new               (gfloat x_1,
                                                         gfloat y_1,
                                                         gfloat x_2,
                                                         gfloat y_2);

Allocates a new ClutterActorBox using the passed coordinates for the top left and bottom right points

Since 1.0

clutter_actor_box_copy ()

ClutterActorBox *   clutter_actor_box_copy              (const ClutterActorBox *box);

Copies box

Since 1.0

clutter_actor_box_free ()

void                clutter_actor_box_free              (ClutterActorBox *box);

Frees a ClutterActorBox allocated using clutter_actor_box_new() or clutter_actor_box_copy()

Since 1.0

clutter_actor_box_equal ()

gboolean            clutter_actor_box_equal             (const ClutterActorBox *box_a,
                                                         const ClutterActorBox *box_b);

Checks box_a and box_b for equality

Since 1.0

clutter_actor_box_get_x ()

gfloat              clutter_actor_box_get_x             (const ClutterActorBox *box);

Retrieves the X coordinate of the origin of box