U Pe@sPdZdZddlmZddlmZddlmZmZddlm Z GdddeZ d S) aF Kinetic effect ============== .. versionadded:: 1.7.0 The :class:`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 :attr:`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 :attr:`KineticEffect.friction`. The computed value will be stored in :attr:`KineticEffect.value`. The output of this `value` could be:: 46.30038145219605 54.58302451968686 61.9229016256196 # ... ) KineticEffect)time)EventDispatcher)NumericPropertyBooleanProperty)ClockcseZdZdZedZedZedZedZ edZ edZ edZ edZ fd d Zd d ZdddZdddZdddZddZddZZS)rzIKinetic effect class. See module documentation for more information. rg?Fg?g?g rh?c s,g|_t|jd|_tt|jf|dSNr)historyrZcreate_triggerupdate_velocitytrigger_velocity_updatesuperr__init__)selfkwargs __class__8/tmp/pip-unpacked-wheel-xzebddm3/kivy/effects/kinetic.pyrus zKineticEffect.__init__cCs&t||jkrd|_|j|7_dSr )abs min_distancevelocityvalue)rdistancerrrapply_distance{szKineticEffect.apply_distanceNcCs&d|_|pt}d|_||fg|_dS)a Start the movement. :Parameters: `val`: float or int Value of the movement `t`: float, defaults to None Time when the movement happen. If no time is set, it will use time.time() TrN) is_manualrrr )rvaltrrrstarts  zKineticEffect.startcCsV|pt}||jdd}|||j||ft|j|jkrR|jddS)zKUpdate the movement. See :meth:`start` for the arguments. rN)rr rappendlen max_historypop)rrrrrrrupdates   zKineticEffect.updatecCsd|_|pt}||jdd}||||f}|jd}|jD] }|d|ddkr`qf|}qD|d|d}t|d|d}|t|d|_|dS)zIStop the movement. See :meth:`start` for the arguments. Frr rgUUUUUU?g-C6?N)rrr rrmaxrr )rrrrZ newest_sampleZ old_samplesampledurationrrrstops    zKineticEffect.stopcCsd|_|dS)zCancel a movement. This can be used in case :meth:`stop` cannot be called. It will reset :attr:`is_manual` to False, and compute the movement if the velocity is > 0. FN)rr )rrrrcancelszKineticEffect.cancelcCsVt|j|jkrd|_dS|j|j|j||j8_||j||dS)zX(internal) Update the velocity according to the frametime and friction. rN)rr min_velocityfrictionstd_dtrr )rdtrrrr s  zKineticEffect.update_velocity)N)N)N)__name__ __module__ __qualname____doc__rrr,rrrr#rr+r-rrrr%r)r*r __classcell__rrrrr0s      rN) r2__all__rZ kivy.eventrZkivy.propertiesrrZ kivy.clockrrrrrrs &