/**
* Manager handling the keyboard events.
*
* @author Alain Pitiot
* @version 2022.2.3
* @copyright (c) 2017-2020 Ilixa Ltd. (http://ilixa.com) (c) 2020-2022 Open Science Tools Ltd. (https://opensciencetools.org)
* @license Distributed under the terms of the MIT License
*/
import { Clock, MonotonicClock } from "../util/Clock.js";
import { PsychObject } from "../util/PsychObject.js";
import { EventManager } from "./EventManager.js";
import { PsychoJS } from "./PsychoJS.js";
/**
* <pKeyPress holds information about a key that has been pressed, such as the duration of the press.</p>
*/
export class KeyPress
{
/**
* @memberof module:core
* @param {string} code - W3C Key Code
* @param {number} tDown - time of key press (keydown event) relative to the global Monotonic Clock
* @param {string | undefined} name - pyglet key name
*/
constructor(code, tDown, name)
{
this.code = code;
this.tDown = tDown;
this.name = (typeof name !== "undefined") ? name : EventManager.w3c2pyglet(code);
// duration of the keypress (time between keydown and keyup events) or undefined if there was no keyup
this.duration = undefined;
// time of keydown event relative to Keyboard clock:
this.rt = undefined;
}
}
/**
* <p>This manager handles all keyboard events. It is a substitute for the keyboard component of EventManager. </p>
*
* @extends PsychObject
*/
export class Keyboard extends PsychObject
{
/**
* @memberof module:core
* @param {Object} options
* @param {module:core.PsychoJS} options.psychoJS - the PsychoJS instance
* @param {number} [options.bufferSize= 10000] - the maximum size of the circular keyboard event buffer
* @param {boolean} [options.waitForStart= false] - whether or not to wait for a call to module:core.Keyboard#start
* before recording keyboard events
* @param {Clock} [options.clock= undefined] - an optional clock
* @param {boolean} [options.autoLog= false] - whether or not to log
*/
constructor({
psychoJS,
bufferSize = 10000,
waitForStart = false,
clock,
autoLog = false,
} = {})
{
super(psychoJS);
if (typeof clock === "undefined")
{
clock = new Clock();
} // this._psychoJS.monotonicClock;
this._addAttribute("bufferSize", bufferSize);
this._addAttribute("waitForStart", waitForStart);
this._addAttribute("clock", clock);
this._addAttribute("autoLog", autoLog);
// start recording key events if need be:
this._addAttribute("status", (waitForStart) ? PsychoJS.Status.NOT_STARTED : PsychoJS.Status.STARTED);
// setup circular buffer:
this.clearEvents();
// add key listeners:
this._addKeyListeners();
}
/**
* Start recording keyboard events.
*/
start()
{
this._status = PsychoJS.Status.STARTED;
}
/**
* Stop recording keyboard events.
*/
stop()
{
this._status = PsychoJS.Status.STOPPED;
}
/**
* @typedef Keyboard.KeyEvent
*
* @property {string} W3C key code
* @property {string} W3C key
* @property {string} pyglet key
* @property {module:core.Keyboard#KeyStatus} key status
* @property {number} timestamp (in seconds)
*/
/**
* Get the list of those keyboard events still in the buffer, i.e. those that have not been
* previously cleared by calls to getKeys with clear = true.
*
* @return {Keyboard.KeyEvent[]} the list of events still in the buffer
*/
getEvents()
{
if (this._bufferLength === 0)
{
return [];
}
// iterate over the buffer, from start to end, and discard the null event:
let filteredEvents = [];
const bufferWrap = (this._bufferLength === this._bufferSize);
let i = bufferWrap ? this._bufferIndex : -1;
do
{
i = (i + 1) % this._bufferSize;
const keyEvent = this._circularBuffer[i];
if (keyEvent)
{
filteredEvents.push(keyEvent);
}
} while (i !== this._bufferIndex);
return filteredEvents;
}
/**
* Get the list of keys pressed or pushed by the participant.
*
* @param {Object} options
* @param {string[]} [options.keyList= []]] - the list of keys to consider. If keyList is empty, we consider all keys.
* Note that we use pyglet keys here, to make the PsychoJs code more homogeneous with PsychoPy.
* @param {boolean} [options.waitRelease= true] - whether or not to include those keys pressed but not released. If
* waitRelease = false, key presses without a corresponding key release will have an undefined duration.
* @param {boolean} [options.clear= false] - whether or not to keep in the buffer the key presses or pushes for a subsequent call to getKeys. If a keyList has been given and clear = true, we only remove from the buffer those keys in keyList
* @return {KeyPress[]} the list of keys that were pressed (keydown followed by keyup) or pushed
* (keydown with no subsequent keyup at the time getKeys is called).
*/
getKeys({
keyList = [],
waitRelease = true,
clear = true,
} = {})
{
// if nothing in the buffer, return immediately:
if (this._bufferLength === 0)
{
return [];
}
let keyPresses = [];
// iterate over the circular buffer, looking for keyup events:
const bufferWrap = (this._bufferLength === this._bufferSize);
let i = bufferWrap ? this._bufferIndex : -1;
do
{
i = (i + 1) % this._bufferSize;
const keyEvent = this._circularBuffer[i];
if (keyEvent && keyEvent.status === Keyboard.KeyStatus.KEY_UP)
{
// if the keylist is empty of the key is in the keyList:
if (keyList.length === 0 || keyList.includes(keyEvent.pigletKey))
{
// look for a corresponding, preceding keydown event:
const precedingKeydownIndex = keyEvent.keydownIndex;
if (typeof precedingKeydownIndex !== "undefined")
{
const precedingKeydownEvent = this._circularBuffer[precedingKeydownIndex];
if (precedingKeydownEvent)
{
// prepare KeyPress and add it to the array:
const tDown = precedingKeydownEvent.timestamp;
const keyPress = new KeyPress(keyEvent.code, tDown, keyEvent.pigletKey);
keyPress.rt = tDown - this._clock.getLastResetTime();
keyPress.duration = keyEvent.timestamp - precedingKeydownEvent.timestamp;
keyPresses.push(keyPress);
if (clear)
{
this._circularBuffer[precedingKeydownIndex] = null;
}
}
}
/* old approach: the circular buffer contains independent keydown and keyup events:
let j = i - 1;
do {
if (j === -1 && bufferWrap)
j = this._bufferSize - 1;
const precedingKeyEvent = this._circularBuffer[j];
if (precedingKeyEvent &&
(precedingKeyEvent.key === keyEvent.key) &&
(precedingKeyEvent.status === Keyboard.KeyStatus.KEY_DOWN)) {
duration = keyEvent.timestamp - precedingKeyEvent.timestamp;
if (clear)
// rather than modify the circular buffer, which is computationally expensive,
// we simply nullify the keyEvent:
this._circularBuffer[j] = null;
break;
}
j = j - 1;
} while ((bufferWrap && j !== i) || (j > -1));*/
if (clear)
{
this._circularBuffer[i] = null;
}
}
}
} while (i !== this._bufferIndex);
// if waitRelease = false, we iterate again over the map of unmatched keydown events:
if (!waitRelease)
{
for (const unmatchedKeyDownIndex of this._unmatchedKeydownMap.values())
{
const keyEvent = this._circularBuffer[unmatchedKeyDownIndex];
if (keyEvent)
{
// check that the key is in the keyList:
if (keyList.length === 0 || keyList.includes(keyEvent.pigletKey))
{
const tDown = keyEvent.timestamp;
const keyPress = new KeyPress(keyEvent.code, tDown, keyEvent.pigletKey);
keyPress.rt = tDown - this._clock.getLastResetTime();
keyPresses.push(keyPress);
if (clear)
{
this._unmatchedKeydownMap.delete(keyEvent.code);
this._circularBuffer[unmatchedKeyDownIndex] = null;
}
}
}
}
/* old approach: the circular buffer contains independent keydown and keyup events:
let i = bufferWrap ? this._bufferIndex : -1;
do {
i = (i + 1) % this._bufferSize;
const keyEvent = this._circularBuffer[i];
if (keyEvent && keyEvent.status === Keyboard.KeyStatus.KEY_DOWN) {
// check that the key is in the keyList:
const pigletKey = EventManager.w3c2pyglet(keyEvent.code);
if (keyList.length === 0 || keyList.includes(pigletKey)) {
keyPresses.push(new KeyPress(keyEvent.code, keyEvent.timestamp, pigletKey));
if (clear)
// rather than modify the circular buffer, which is computationally expensive, we simply nullify
// the keyEvent:
this._circularBuffer[i] = null;
}
}
} while (i !== this._bufferIndex);*/
}
// if clear = true and the keyList is empty, we clear all the events:
if (clear && keyList.length === 0)
{
this.clearEvents();
}
return keyPresses;
}
/**
* Clear all events and resets the circular buffers.
*/
clearEvents()
{
// circular buffer of key events (keydown and keyup):
this._circularBuffer = new Array(this._bufferSize);
this._bufferLength = 0;
this._bufferIndex = -1;
this._previousKeydownKey = undefined;
// (code => circular buffer index) map of keydown events not yet matched to keyup events:
this._unmatchedKeydownMap = new Map();
}
/**
* Test whether a list of KeyPress's contains one with a particular name.
*
* @param {module:core.KeyPress[]} keypressList - list of KeyPress's
* @param {string } keyName - pyglet key name, e.g. 'escape', 'left'
* @return {boolean} whether or not a KeyPress with the given pyglet key name is present in the list
*/
static includes(keypressList, keyName)
{
if (!Array.isArray(keypressList))
{
return false;
}
const value = keypressList.find((keypress) => keypress.name === keyName);
return (typeof value !== "undefined");
}
/**
* Add key listeners to the document.
*
* @protected
*/
_addKeyListeners()
{
this._previousKeydownKey = undefined;
const self = this;
// add a keydown listener:
window.addEventListener("keydown", (event) =>
// document.addEventListener("keydown", (event) =>
{
// only consider non-repeat events, i.e. only the first keydown event associated with a participant
// holding a key down:
if (event.repeat)
{
return;
}
const timestamp = MonotonicClock.getReferenceTime(); // timestamp in seconds
if (this._status !== PsychoJS.Status.STARTED)
{
return;
}
/**
* DEPRECATED: we now use event.repeat
// since keydown events will repeat as long as the key is pressed, we need to track the last pressed key:
if (event.key === self._previousKeydownKey)
return;
*/
self._previousKeydownKey = event.key;
let code = event.code;
// take care of legacy Microsoft browsers (IE11 and pre-Chromium Edge):
if (typeof code === "undefined")
{
code = EventManager.keycode2w3c(event.keyCode);
}
let pigletKey = EventManager.w3c2pyglet(code);
self._bufferIndex = (self._bufferIndex + 1) % self._bufferSize;
self._bufferLength = Math.min(self._bufferLength + 1, self._bufferSize);
self._circularBuffer[self._bufferIndex] = {
code,
key: event.key,
pigletKey,
status: Keyboard.KeyStatus.KEY_DOWN,
timestamp,
};
self._unmatchedKeydownMap.set(event.code, self._bufferIndex);
self._psychoJS.logger.trace("keydown: ", event.key);
event.stopPropagation();
});
// add a keyup listener:
window.addEventListener("keyup", (event) =>
// document.addEventListener("keyup", (event) =>
{
const timestamp = MonotonicClock.getReferenceTime(); // timestamp in seconds
if (this._status !== PsychoJS.Status.STARTED)
{
return;
}
self._previousKeydownKey = undefined;
let code = event.code;
// take care of legacy Microsoft Edge:
if (typeof code === "undefined")
{
code = EventManager.keycode2w3c(event.keyCode);
}
let pigletKey = EventManager.w3c2pyglet(code);
self._bufferIndex = (self._bufferIndex + 1) % self._bufferSize;
self._bufferLength = Math.min(self._bufferLength + 1, self._bufferSize);
self._circularBuffer[self._bufferIndex] = {
code,
key: event.key,
pigletKey,
status: Keyboard.KeyStatus.KEY_UP,
timestamp,
};
// get the corresponding keydown event
// note: if more keys are down than there are slots in the circular buffer, there might
// not be a corresponding keydown event
const correspondingKeydownIndex = self._unmatchedKeydownMap.get(event.code);
if (typeof correspondingKeydownIndex !== "undefined")
{
self._circularBuffer[self._bufferIndex].keydownIndex = correspondingKeydownIndex;
self._unmatchedKeydownMap.delete(event.code);
}
self._psychoJS.logger.trace("keyup: ", event.key);
event.stopPropagation();
});
}
}
/**
* Keyboard KeyStatus.
*
* @enum {Symbol}
* @readonly
*/
Keyboard.KeyStatus = {
KEY_DOWN: Symbol.for("KEY_DOWN"),
KEY_UP: Symbol.for("KEY_UP"),
};