Next: ClutterBackend, Previous: ClutterActor, Up: Top
A class for calculating an alpha value as a function of time.
<clutter-alpha> is a class for calculating an integer value between 0 and
‘CLUTTER_ALPHA_MAX_ALPHA’ as a function of time. You should provide a
<clutter-timeline> and bind it to the <clutter-alpha> object; you
should also provide a function returning the alpha value depending on the
position inside the timeline; this function will be executed each time a new
frame in the <clutter-timeline> is reached. Since the alpha function is
controlled by the timeline instance, you can pause or stop the
<clutter-alpha> from calling the alpha function by controlling the
<clutter-timeline> object.
<clutter-alpha> is used to "drive" a <clutter-behaviour> instance.
(The missing figure, alpha-functions
Derives from
<g-initially-unowned>.This class defines the following slots:
timeline- Timeline
alpha- Alpha value
<clutter-alpha>)Creates a new
<clutter-alpha>instance. You must set a function to compute the alpha value usingclutter-alpha-set-funcand bind a<clutter-timeline>object to the<clutter-alpha>instance usingclutter-alpha-set-timeline.You should use the newly created
<clutter-alpha>instance inside a<clutter-behaviour>object.
- ret
- the newly created empty
<clutter-alpha>instance.Since 0.2
<clutter-alpha>) (ret unsigned-int32)Query the current alpha value.
- alpha
- A
<clutter-alpha>- ret
- The current alpha value for the alpha
Since 0.2
<clutter-alpha>) (closure <gclosure>)Sets the
<gclosure>used to compute the alpha value at each frame of the<clutter-timeline>bound to alpha.
- alpha
- A
<clutter-alpha>- closure
- A
<gclosure>Since 0.8