JSFiddle - React, Tailwind, and code Playground

by zoe chen

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<h4>Transitioning a fillStyle over 2.50 seconds</h4>
<!-- <br> --><!-- <button id=again>Again</button> -->
<!-- <br> --><!-- <canvas id="canvas" width=300 height=300></canvas> -->
<canvas></canvas>

CSS

body{ background-color: ivory; }
/* #canvas{border:1px solid red;} */

JavaScript

var canvas = document.querySelector("canvas");
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
var ctx = canvas.getContext("2d");
var duration = 2.50;
var rgbStart = '#fff';
var rgbEnd = '#bbb';
var opacitySteps = parseInt(60*duration);
var opacityStep = 0;

var TAU = 2 * Math.PI;

times = [];
function loop() {
	var opacity = 100*(opacityStep/opacitySteps);
  if(opacityStep >= opacityStep - 1){
    opacity = 100;
  }
  ctx.clearRect(0, 0, canvas.width, canvas.height);
  update();
  draw();
  requestAnimationFrame(loop);
}

function Ball (startX, startY, startVelX, startVelY) {
  this.x = startX || Math.random() * canvas.width;
  this.y = startY || Math.random() * canvas.height;
  this.vel = {
    x: startVelX || Math.random() * 2 - 1,
    y: startVelY || Math.random() * 2 - 1
  };
  this.update = function(canvas) {
    if (this.x > canvas.width + 50 || this.x < -50) {
      this.vel.x = -this.vel.x;
    }
    if (this.y > canvas.height + 50 || this.y < -50) {
      this.vel.y = -this.vel.y;
    }
    this.x += this.vel.x;
    this.y += this.vel.y;
  };
  this.draw = function(ctx, can) {
    ctx.beginPath();
    ctx.globalAlpha = .4;
    ctx.fillStyle = '#448fda';
    ctx.arc((0.5 + this.x) | 0, (0.5 + this.y) | 0, 3, 0, TAU, false);
    ctx.fill();
  }
}

var balls = [];
for (var i = 0; i < canvas.width * canvas.height / (65*65); i++) {
  balls.push(new Ball(Math.random() * canvas.width, Math.random() * canvas.height));
}

var lastTime = Date.now();
function update() {
  var diff = Date.now() - lastTime;
  for (var frame = 0; frame * 16.6667 < diff; frame++) {
    for (var index = 0; index < balls.length; index++) {
      balls[index].update(canvas);
    }
  }
  lastTime = Date.now();
}
var mouseX = -1e9, mouseY = -1e9;
document.addEventListener('mousemove', function(event) {
  mouseX = event.clientX;
  mouseY = event.clientY;
});

function distMouse(ball) {
  return Math.hypot(ball.x - mouseX, ball.y - mouseY);
}

function draw() {
 ...