Table Of Contents
Kinetic effect¶
New in version 1.7.0.
The KineticEffect is the base class that is used to compute the velocity out of a movement. When the movement is finished, the effect will compute the position of the movement according to the velocity, and reduce the velocity with a friction. The movement stop until the velocity is 0.
Conceptually, the usage could be:
>>> effect = KineticEffect()
>>> effect.start(10)
>>> effect.update(15)
>>> effect.update(30)
>>> effect.stop(48)
Over the time, you will start a movement of a value, update it, and stop the movement. At this time, you’ll get the movement value into KineticEffect.value. On the example i’ve typed manually, the computed velocity will be:
>>> effect.velocity
3.1619100231163046
After multiple clock interaction, the velocity will decrease according to KineticEffect.friction. The computed value will be stored in KineticEffect.value. The output of this value could be:
46.30038145219605
54.58302451968686
61.9229016256196
# ...
- class kivy.effects.kinetic.KineticEffect(**kwargs)¶
Bases: kivy.event.EventDispatcher
Kinetic effect class. See module documentation for more information.
- cancel()¶
Cancel a movement. This can be used in case of stop() cannot be called. It will reset is_manual to False, and compute the movement if the velocity is > 0.
- friction¶
Friction to apply on the velocity
velocity is a NumericProperty, default to 0.05
- is_manual¶
Indicate if a movement is in progress (True) or not (False).
velocity is a BooleanProperty, default to False
- max_history¶
Save up to max_history movement value into the history. This is used for correctly calculating the velocity according to the movement.
max_history is a NumericProperty, default to 5.
- start(val, t=None)¶
Start the movement.
Parameters : - val: float or int
Value of the movement
- t: float, default to None
Time when the movement happen. If no time is set, it will use time.time()
- update_velocity(dt)¶
(internal) Update the velocity according to a frametime and the friction.
- value¶
Value (during the movement and computed) of the effect.
velocity is a NumericProperty, default to 0
- velocity¶
Velocity of the movement.
velocity is a NumericProperty, default to 0