Scheduler

util Scheduler

A scheduler helps run the main loop by managing scheduled functions, called tasks, after each frame is displayed.

Tasks are either another Scheduler, or a JavaScript functions returning one of the following codes:

  • Scheduler.Event.NEXT: Move onto the next task *without* rendering the scene first.
  • Scheduler.Event.FLIP_REPEAT: Render the scene and repeat the task.
  • Scheduler.Event.FLIP_NEXT: Render the scene and move onto the next task.
  • Scheduler.Event.QUIT: Quit the scheduler.

It is possible to create sub-schedulers, e.g. to handle loops. Sub-schedulers are added to a parent scheduler as a normal task would be by calling scheduler.add(subScheduler).

Conditional branching is also available: scheduler.addConditionalBranches

Constructor

new Scheduler(psychoJS)

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Parameters:
Name Type Description
psychoJS module:core.PsychoJS

the PsychoJS instance

Members

(static, readonly) Event :Symbol

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Properties:
Name Type Description
NEXT Symbol

Move onto the next task without rendering the scene first.
FLIP_REPEAT Symbol

Render the scene and repeat the task.
FLIP_NEXT Symbol

Render the scene and move onto the next task.
QUIT Symbol

Quit the scheduler.

Events.

Type:
  • Symbol

(static, readonly) Status :Symbol

Source:
Properties:
Name Type Description
RUNNING Symbol

The Scheduler is running.
STOPPED Symbol

The Scheduler is stopped.

Status.

Type:
  • Symbol

status

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Get the status of the scheduler.

Methods

add(task, …args)

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Schedule a new task.

Parameters:
Name Type Attributes Description
task Scheduler~Task | Scheduler

the task to be scheduled
args * <repeatable>

arguments for that task

addConditional(condition, thenScheduler, elseScheduler)

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Schedule a series of task or another, based on a condition.

Note: the tasks are sub-schedulers.

Parameters:
Name Type Description
condition Scheduler~Condition

the condition
thenScheduler Scheduler

the Scheduler to be run if the condition is satisfied
elseScheduler Scheduler

the Scheduler to be run if the condition is not satisfied

start() → {Promise.<void>}

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Start this scheduler.

Note: tasks are run after each animation frame.

Returns:

a promise resolved when the scheduler stops, e.g. when the experiments finishes

Type
Promise.<void>

stop()

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Stop this scheduler.

Type Definitions

Condition() → {boolean}

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Condition evaluated when the task is run.

Returns:
Type
boolean

Task(argsopt)

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Task to be run by the scheduler.

Parameters:
Name Type Attributes Description
args * <optional>

optional arguments