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refactor(frontend): event threshold handling 

* Created const and utils helpers
* Created point class
This commit is contained in:
Florent Chehab 2020-05-02 21:17:46 +02:00
parent 7a81491ffa
commit 67fd33c66b
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GPG Key ID: 9A0CE018889EA246
4 changed files with 74 additions and 27 deletions
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22
src/js/classes/Point.js Normal file
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@ -0,0 +1,22 @@
import {computeDist} from "../utils";
class Point {
/**
* @param {number} x
* @param {number} y
*/
constructor(x, y) {
this.x = x;
this.y = y;
}
/**
* @param {Point} otherPoint
* @returns {number}
*/
distTo(otherPoint) {
return computeDist(this, otherPoint);
}
}
export default Point;

2
src/js/const.js Normal file
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@ -0,0 +1,2 @@
export const POINTER_EVENT_THRESHOLD_MIN_DIST_DELTA = 10; // 10px
export const POINTER_EVENT_THRESHOLD_MIN_TIME_DELTA = 100; // 100ms

18
src/js/utils.js Normal file
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@ -0,0 +1,18 @@
/**
* Compute the distance between two points
* @param {Point} p1
* @param {Point} p2
*/
export function computeDist(p1, p2) {
return Math.sqrt(
Math.pow(p1.x - p2.x, 2) + Math.pow(p1.y - p2.y, 2)
);
}
/**
* Return the current time in ms since 1970
* @returns {number}
*/
export function getCurrentTimeMs() {
return (new Date()).getTime();
}

59
src/js/whiteboard.js
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@ -1,4 +1,7 @@
import { dom } from "@fortawesome/fontawesome-svg-core";
import {computeDist, getCurrentTimeMs} from "./utils";
import Point from "./classes/Point";
import {POINTER_EVENT_THRESHOLD_MIN_DIST_DELTA, POINTER_EVENT_THRESHOLD_MIN_TIME_DELTA} from "./const";
const whiteboard = {
canvas: null,
@ -42,8 +45,10 @@ const whiteboard = {
},
readOnly: true,
lastPointerSentTime: 0,
lastPointerX: 0,
lastPointerY: 0,
/**
* @type Point
*/
lastPointerPosition: new Point(0, 0),
loadWhiteboard: function (whiteboardContainer, newSettings) {
var svgns = "http://www.w3.org/2000/svg";
var _this = this;
@ -164,17 +169,16 @@ const whiteboard = {
}
if (_this.readOnly) return;
var currX = (e.offsetX || e.pageX - $(e.target).offset().left);
var currY = (e.offsetY || e.pageY - $(e.target).offset().top);
const currX = (e.offsetX || e.pageX - $(e.target).offset().left);
const currY = (e.offsetY || e.pageY - $(e.target).offset().top);
const newPointerPosition = new Point(currX, currY);
var pointerSentTime = (new Date()).getTime();
if (pointerSentTime - _this.lastPointerSentTime > 100) {
var dist = Math.pow(_this.lastPointerX-currX,2)+Math.pow(_this.lastPointerY-currY,2);
if (dist>100) {
const pointerSentTime = getCurrentTimeMs();
if (pointerSentTime - _this.lastPointerSentTime > POINTER_EVENT_THRESHOLD_MIN_TIME_DELTA) {
if (_this.lastPointerPosition.distTo(newPointerPosition) > POINTER_EVENT_THRESHOLD_MIN_DIST_DELTA) {
_this.lastPointerSentTime = pointerSentTime;
_this.lastPointerX = currX;
_this.lastPointerY = currY;
_this.sendFunction({ "t": "cursor", "event": "move", "d": [currX, currY], "username": _this.settings.username });
_this.lastPointerPosition = newPointerPosition;
_this.sendFunction({ "t": "cursor", "event": "move", "d": [newPointerPosition.x, newPointerPosition.y], "username": _this.settings.username });
}
}
})
@ -337,8 +341,7 @@ const whiteboard = {
}
var currX = e.currX || (e.offsetX || e.pageX - $(e.target).offset().left);
var currY = e.currY || (e.offsetY || e.pageY - $(e.target).offset().top);
_this.currX = currX;
_this.currY = currY;
window.requestAnimationFrame(function () {
if ((!currX || !currY) && e.touches && e.touches[0]) {
var touche = e.touches[0];
@ -405,14 +408,14 @@ const whiteboard = {
_this.prevX = currX;
_this.prevY = currY;
});
var pointerSentTime = (new Date()).getTime();
if (pointerSentTime - _this.lastPointerSentTime > 100) {
var dist = Math.pow(_this.lastPointerX-currX,2)+Math.pow(_this.lastPointerY-currY,2);
if (dist>100) {
const pointerSentTime = getCurrentTimeMs();
if (pointerSentTime - _this.lastPointerSentTime > POINTER_EVENT_THRESHOLD_MIN_TIME_DELTA) {
const newPointerPosition = new Point(currX, currY);
if (_this.lastPointerPosition.distTo(newPointerPosition) > POINTER_EVENT_THRESHOLD_MIN_DIST_DELTA) {
_this.lastPointerSentTime = pointerSentTime;
_this.lastPointerX = currX;
_this.lastPointerY = currY;
_this.sendFunction({ "t": "cursor", "event": "move", "d": [currX, currY], "username": _this.settings.username });
_this.lastPointerPosition = newPointerPosition;
_this.sendFunction({ "t": "cursor", "event": "move", "d": [newPointerPosition.x, newPointerPosition.y], "username": _this.settings.username });
}
}
},
@ -669,14 +672,16 @@ const whiteboard = {
if ($(e.target).hasClass("removeIcon")) {
currX += textBox.width() - 4;
}
var pointerSentTime = (new Date()).getTime();
if (pointerSentTime - _this.lastPointerSentTime > 100) {
var dist = Math.pow(_this.lastPointerX-currX,2)+Math.pow(_this.lastPointerY-currY,2);
if (dist>100) {
const pointerSentTime = getCurrentTimeMs();
const newPointerPosition = new Point(currX, currY);
// At least 100 ms between messages to reduce server load
if (pointerSentTime - _this.lastPointerSentTime > POINTER_EVENT_THRESHOLD_MIN_TIME_DELTA) {
// Minimal distance between messages to reduce server load
if (_this.lastPointerPosition.distTo(newPointerPosition) > POINTER_EVENT_THRESHOLD_MIN_DIST_DELTA) {
_this.lastPointerSentTime = pointerSentTime;
_this.lastPointerX = currX;
_this.lastPointerY = currY;
_this.sendFunction({ "t": "cursor", "event": "move", "d": [currX, currY], "username": _this.settings.username });
_this.lastPointerPosition = newPointerPosition;
_this.sendFunction({ "t": "cursor", "event": "move", "d": [newPointerPosition.x, newPointerPosition.y], "username": _this.settings.username });
}
}
})