ClutterAlpha custom properties for ClutterScript

ClutterAlpha defines a custom function property for ClutterScript which allows to reference a custom alpha function available in the source code. Setting the function property is equivalent to calling clutter_alpha_set_func() with the specified function name. No user data or GDestroyNotify is available to be passed.

The following JSON fragment defines a ClutterAlpha using a ClutterTimeline with id "sine-timeline" and an alpha function called my_sine_alpha. The defined ClutterAlpha instance can be reused in multiple ClutterBehaviour definitions or for ClutterAnimation definitions.

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{
  "id" : "sine-alpha",
  "timeline" : {
    "id" : "sine-timeline",
    "duration" : 500,
    "loop" : true
  },
  "function" : "my_sine_alpha"
}

ClutterAlphaFunc ()

gdouble
(*ClutterAlphaFunc) (ClutterAlpha *alpha,
                     gpointer user_data);

A function returning a value depending on the position of the ClutterTimeline bound to alpha .

Since 0.2

clutter_alpha_new ()

ClutterAlpha *
clutter_alpha_new (void);

Creates a new ClutterAlpha instance. You must set a function to compute the alpha value using clutter_alpha_set_func() and bind a ClutterTimeline object to the ClutterAlpha instance using clutter_alpha_set_timeline().

You should use the newly created ClutterAlpha instance inside a ClutterBehaviour object.

Since 0.2

clutter_alpha_new_full ()

ClutterAlpha *
clutter_alpha_new_full (ClutterTimeline *timeline,
                        gulong mode);

Creates a new ClutterAlpha instance and sets the timeline and animation mode.

See also clutter_alpha_set_timeline() and clutter_alpha_set_mode().

Since 1.0

clutter_alpha_new_with_func ()

ClutterAlpha *
clutter_alpha_new_with_func (ClutterTimeline *timeline,
                             ClutterAlphaFunc func,
                             gpointer data,
                             GDestroyNotify destroy);

Creates a new ClutterAlpha instances and sets the timeline and the alpha function.

This function will not register func as a global alpha function.

See also clutter_alpha_set_timeline() and clutter_alpha_set_func().

Since 1.0

clutter_alpha_set_timeline ()

void
clutter_alpha_set_timeline (ClutterAlpha *alpha,
                            ClutterTimeline *timeline);

Binds alpha to timeline .

Since 0.2

clutter_alpha_get_timeline ()

ClutterTimeline *
clutter_alpha_get_timeline (ClutterAlpha *alpha);

Gets the ClutterTimeline bound to alpha .

Since 0.2

clutter_alpha_set_mode ()

void
clutter_alpha_set_mode (ClutterAlpha *alpha,
                        gulong mode);

Sets the progress function of alpha using the symbolic value of mode , as taken by the ClutterAnimationMode enumeration or using the value returned by clutter_alpha_register_func().

Since 1.0

clutter_alpha_get_mode ()

gulong
clutter_alpha_get_mode (ClutterAlpha *alpha);

Retrieves the ClutterAnimationMode used by alpha .

Since 1.0

clutter_alpha_get_alpha ()

gdouble
clutter_alpha_get_alpha (ClutterAlpha *alpha);

Query the current alpha value.

Since 0.2

clutter_alpha_set_func ()

void
clutter_alpha_set_func (ClutterAlpha *alpha,
                        ClutterAlphaFunc func,
                        gpointer data,
                        GDestroyNotify destroy);

Sets the ClutterAlphaFunc function used to compute the alpha value at each frame of the ClutterTimeline bound to alpha .

This function will not register func as a global alpha function.

Since 0.2

clutter_alpha_set_closure ()

void
clutter_alpha_set_closure (ClutterAlpha *alpha,
                           GClosure *closure);

Sets the GClosure used to compute the alpha value at each frame of the ClutterTimeline bound to alpha .

Since 0.8

clutter_alpha_register_closure ()

gulong
clutter_alpha_register_closure (GClosure *closure);

GClosure variant of clutter_alpha_register_func().

Registers a global alpha function and returns its logical id to be used by clutter_alpha_set_mode() or by ClutterAnimation.

The logical id is always greater than CLUTTER_ANIMATION_LAST.

Rename to: clutter_alpha_register_func

Since 1.0

clutter_alpha_register_func ()

gulong
clutter_alpha_register_func (ClutterAlphaFunc func,
                             gpointer data);

Registers a global alpha function and returns its logical id to be used by clutter_alpha_set_mode() or by ClutterAnimation.

The logical id is always greater than CLUTTER_ANIMATION_LAST.

Since 1.0

ClutterAlpha

typedef struct _ClutterAlpha ClutterAlpha;

ClutterAlpha combines a ClutterTimeline and a function. The contents of the ClutterAlpha structure are private and should only be accessed using the provided API.

Since 0.2

struct ClutterAlphaClass

struct ClutterAlphaClass {
};

Base class for ClutterAlpha

Since 0.2

The “alpha” property

  “alpha”                    gdouble

The alpha value as computed by the alpha function. The linear interval is 0.0 to 1.0, but the Alpha allows overshooting by one unit in each direction, so the valid interval is -1.0 to 2.0.

Flags: Read

Allowed values: [-1,2]

Default value: 0

Since 0.2

The “mode” property

  “mode”                     gulong

The progress function logical id - either a value from the ClutterAnimationMode enumeration or a value returned by clutter_alpha_register_func().

If CLUTTER_CUSTOM_MODE is used then the function set using clutter_alpha_set_closure() or clutter_alpha_set_func() will be used.

Flags: Read / Write / Construct

Since 1.0

The “timeline” property

  “timeline”                 ClutterTimeline *

A ClutterTimeline instance used to drive the alpha function.

Flags: Read / Write

Since 0.2