JSFiddle - React, Tailwind, and code Playground

by Yaroslav Samardak

HTML

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>JS Bin</title>
</head>
<body>
  <canvas id="canvas" width="400" height="400"></canvas>
</body>
</html>

CSS

body {
  margin: 0;
  display: flex;
  width: 100vw;
  height: 100vh;
  align-items: center;
  justify-content: center;
  background-color: #F0F0F0;
}

canvas {
  background: #FFF;
  width: 200px;
  height: 200px;
  border: 1px solid black;
  border-radius: 4px;
  box-shadow: 0 3px 6px rgba(0,0,0,0.16), 0 3px 6px rgba(0,0,0,0.23);
}

JavaScript

window.onload = () => {
	const c = document.getElementById('canvas').getContext('2d');
  c.lineWidth = 2;
  let r = 0.2, dr = -0.01;
  
	const draw = () => {
    c.clearRect(0, 0, 400, 400);

    c.beginPath();
    c.moveTo(200, 200);
    c.arc(200, 200, 100, r * Math.PI, Math.PI * (2 - r), false);
    c.lineTo(200, 200);
    
    r += dr;
    if (r <= 0.05 || r >= 0.2) dr = -dr;

    c.stroke();
    window.requestAnimationFrame(draw);
  }


	draw();	
}