Added documentation for alpha parameter in Behaviour constructors.

http://bugzilla.clutter-project.org/show_bug.cgi?id=2304

Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>

clutter/clutter-behaviour-depth.c

@@ -197,13 +197,17 @@ clutter_behaviour_depth_init (ClutterBehaviourDepth *depth)
 
 /**
  * clutter_behaviour_depth_new:
- * @alpha: a #ClutterAlpha or %NULL
+ * @alpha: (allow-none): a #ClutterAlpha instance, or %NULL
  * @depth_start: initial value of the depth
  * @depth_end: final value of the depth
  *
  * Creates a new #ClutterBehaviourDepth which can be used to control
  * the ClutterActor:depth property of a set of #ClutterActor<!-- -->s.
  *
+ * If @alpha is not %NULL, the #ClutterBehaviour will take ownership
+ * of the #ClutterAlpha instance. In the case when @alpha is %NULL,
+ * it can be set later with clutter_behaviour_set_alpha().
+ *
  * Return value: the newly created behaviour
  *
  * Since: 0.4

clutter/clutter-behaviour-ellipse.c

@@ -548,7 +548,7 @@ clutter_behaviour_ellipse_init (ClutterBehaviourEllipse * self)
 
 /**
  * clutter_behaviour_ellipse_new:
- * @alpha: a #ClutterAlpha, or %NULL
+ * @alpha: (allow-none): a #ClutterAlpha instance, or %NULL
  * @x: x coordinace of the center
  * @y: y coordiance of the center
  * @width: width of the ellipse
@@ -564,6 +564,10 @@ clutter_behaviour_ellipse_init (ClutterBehaviourEllipse * self)
  * interval <0, 360); if @start is equal to @end, the behaviour will
  * rotate by exacly 360 degrees.
  *
+ * If @alpha is not %NULL, the #ClutterBehaviour will take ownership
+ * of the #ClutterAlpha instance. In the case when @alpha is %NULL,
+ * it can be set later with clutter_behaviour_set_alpha().
+ *
  * Return value: the newly created #ClutterBehaviourEllipse
  *
  * Since: 0.4

clutter/clutter-behaviour-opacity.c

@@ -79,7 +79,7 @@ enum
 
 static GParamSpec *obj_props[PROP_LAST];
 
-static void 
+static void
 alpha_notify_foreach (ClutterBehaviour *behaviour,
 		      ClutterActor     *actor,
 		      gpointer          data)
@@ -219,7 +219,7 @@ clutter_behaviour_opacity_init (ClutterBehaviourOpacity *self)
 
 /**
  * clutter_behaviour_opacity_new:
- * @alpha: a #ClutterAlpha instance, or %NULL
+ * @alpha: (allow-none): a #ClutterAlpha instance, or %NULL
  * @opacity_start: minimum level of opacity
  * @opacity_end: maximum level of opacity
  *
@@ -227,6 +227,10 @@ clutter_behaviour_opacity_init (ClutterBehaviourOpacity *self)
  * which controls the opacity property of every actor, making it
  * change in the interval between @opacity_start and @opacity_end.
  *
+ * If @alpha is not %NULL, the #ClutterBehaviour will take ownership
+ * of the #ClutterAlpha instance. In the case when @alpha is %NULL,
+ * it can be set later with clutter_behaviour_set_alpha().
+ *
  * Return value: the newly created #ClutterBehaviourOpacity
  *
  * Since: 0.2
@@ -236,7 +240,7 @@ clutter_behaviour_opacity_new (ClutterAlpha *alpha,
 			       guint8        opacity_start,
 			       guint8        opacity_end)
 {
-  return g_object_new (CLUTTER_TYPE_BEHAVIOUR_OPACITY, 
+  return g_object_new (CLUTTER_TYPE_BEHAVIOUR_OPACITY,
                        "alpha", alpha,
                        "opacity-start", opacity_start,
                        "opacity-end", opacity_end,

clutter/clutter-behaviour-path.c

@@ -310,7 +310,7 @@ clutter_behaviour_path_init (ClutterBehaviourPath *self)
 
 /**
  * clutter_behaviour_path_new:
- * @alpha: a #ClutterAlpha, or %NULL
+ * @alpha: (allow-none): a #ClutterAlpha instance, or %NULL
  * @path: a #ClutterPath or %NULL for an empty path
  *
  * Creates a new path behaviour. You can use this behaviour to drive
@@ -319,6 +319,10 @@ clutter_behaviour_path_init (ClutterBehaviourPath *self)
  * This will claim the floating reference on the #ClutterPath so you
  * do not need to unref if it.
  *
+ * If @alpha is not %NULL, the #ClutterBehaviour will take ownership
+ * of the #ClutterAlpha instance. In the case when @alpha is %NULL,
+ * it can be set later with clutter_behaviour_set_alpha().
+ *
  * Return value: a #ClutterBehaviour
  *
  * Since: 0.2
@@ -335,12 +339,16 @@ clutter_behaviour_path_new (ClutterAlpha *alpha,
 
 /**
  * clutter_behaviour_path_new_with_description:
- * @alpha: a #ClutterAlpha
+ * @alpha: (allow-none): a #ClutterAlpha instance, or %NULL
  * @desc: a string description of the path
  *
  * Creates a new path behaviour using the path described by @desc. See
  * clutter_path_add_string() for a description of the format.
  *
+ * If @alpha is not %NULL, the #ClutterBehaviour will take ownership
+ * of the #ClutterAlpha instance. In the case when @alpha is %NULL,
+ * it can be set later with clutter_behaviour_set_alpha().
+ *
  * Return value: a #ClutterBehaviour
  *
  * Since: 1.0
@@ -357,7 +365,7 @@ clutter_behaviour_path_new_with_description (ClutterAlpha *alpha,
 
 /**
  * clutter_behaviour_path_new_with_knots:
- * @alpha: a #ClutterAlpha
+ * @alpha: (allow-none): a #ClutterAlpha instance, or %NULL
  * @knots: an array of #ClutterKnot<!-- -->s
  * @n_knots: number of entries in @knots
  *
@@ -368,6 +376,10 @@ clutter_behaviour_path_new_with_description (ClutterAlpha *alpha,
  * %CLUTTER_PATH_MOVE_TO and the subsequent knots are used in
  * %CLUTTER_PATH_LINE_TO<!-- -->s.
  *
+ * If @alpha is not %NULL, the #ClutterBehaviour will take ownership
+ * of the #ClutterAlpha instance. In the case when @alpha is %NULL,
+ * it can be set later with clutter_behaviour_set_alpha().
+ *
  * Return value: a #ClutterBehaviour
  *
  * Since: 1.0

clutter/clutter-behaviour-rotate.c

@@ -411,7 +411,7 @@ clutter_behaviour_rotate_init (ClutterBehaviourRotate *rotate)
 
 /**
  * clutter_behaviour_rotate_new:
- * @alpha: a #ClutterAlpha, or %NULL
+ * @alpha: (allow-none): a #ClutterAlpha instance, or %NULL
  * @axis: the rotation axis
  * @direction: the rotation direction
  * @angle_start: the starting angle in degrees, between 0 and 360.
@@ -423,6 +423,10 @@ clutter_behaviour_rotate_init (ClutterBehaviourRotate *rotate)
  * <0, 360), if angle_start == angle_end, the behaviour will carry out a
  * single rotation of 360 degrees.
  *
+ * If @alpha is not %NULL, the #ClutterBehaviour will take ownership
+ * of the #ClutterAlpha instance. In the case when @alpha is %NULL,
+ * it can be set later with clutter_behaviour_set_alpha().
+ *
  * Return value: the newly created #ClutterBehaviourRotate.
  *
  * Since: 0.4

clutter/clutter-behaviour-scale.c

@@ -97,7 +97,7 @@ clutter_behaviour_scale_alpha_notify (ClutterBehaviour *behave,
   priv = CLUTTER_BEHAVIOUR_SCALE (behave)->priv;
 
   /* Fix the start/end values, avoids potential rounding errors on large
-   * values. 
+   * values.
   */
   if (alpha_value == 1.0)
     {
@@ -114,7 +114,7 @@ clutter_behaviour_scale_alpha_notify (ClutterBehaviour *behave,
       closure.scale_x = (priv->x_scale_end - priv->x_scale_start)
                       * alpha_value
                       + priv->x_scale_start;
-      
+
       closure.scale_y = (priv->y_scale_end - priv->y_scale_start)
                       * alpha_value
                       + priv->y_scale_start;
@@ -290,7 +290,7 @@ clutter_behaviour_scale_init (ClutterBehaviourScale *self)
 
 /**
  * clutter_behaviour_scale_new:
- * @alpha: a #ClutterAlpha
+ * @alpha: (allow-none): a #ClutterAlpha instance, or %NULL
  * @x_scale_start: initial scale factor on the X axis
  * @y_scale_start: initial scale factor on the Y axis
  * @x_scale_end: final scale factor on the X axis
@@ -298,6 +298,10 @@ clutter_behaviour_scale_init (ClutterBehaviourScale *self)
  *
  * Creates a new  #ClutterBehaviourScale instance.
  *
+ * If @alpha is not %NULL, the #ClutterBehaviour will take ownership
+ * of the #ClutterAlpha instance. In the case when @alpha is %NULL,
+ * it can be set later with clutter_behaviour_set_alpha().
+ *
  * Return value: the newly created #ClutterBehaviourScale
  *
  * Since: 0.2