JSFiddle - React, Tailwind, and code Playground

by Lazaro Contreras

HTML

<img src="//www.gravatar.com/avatar/e94f2d3d00aeb7532d8ab431e615792b/?default=&s=124" />
<div class="zoom">
  <canvas id="can" width="124" height="124"></canvas>
</div>

CSS

* {
  margin: 0;
  padding: 0;
}

.zoom {
  position: absolute;
  display: block;
  top: 0;
  left: 0;
  width: 66px;
  height: 66px;
  background: white;
  border: 4px solid white;
  overflow: hidden;
  cursor: none;
}

.zoom::before {
  content: "";
  position: absolute;
  display: block;
  top: 0;
  left: 0;
  width: 66px;
  height: 66px;
  z-index: 1;
  background: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAEIAAABCCAYAAADjVADoAAAACXBIWXMAAC4jAAAuIwF4pT92AAAA8klEQVR4nO2bMQ7CMBTFnqpwH0QFZ0CC8yJxN9QyxNl+L9DYo8P0hu8uJDXv2fxy8DAdDgEOAQ4BLcmz8GuS30T+2pJ8i4fLbL4l2YuHfTbvjQCHAIeAlvqz83Hw+7P6tSX5FA/LbL4l2YqHbTbvjQCHAIcAq9GxGsNbDbw3AhwCHAKsRsdqDG818N4IcAhwCLAaHasxvNXAeyPAIcAhwGp0rMbwVgPvjQCHAIcAq9GxGsNbDbw3AhwCHAKsRsdqDG818N4IcAhwCLAaHasxvNXAeyPAIcAhwGp0rMbwVgPvjQCHAIeAluRV+Hvqf8ye1d/+FBleCsRW2Q8AAAAASUVORK5CYII=');
}

.zoom::after {
  content: "";
  position: absolute;
  display: block;
  /*top: 36px;
  left: 36px;
  width: 30px;
  height: 30px;*/
  top: 29px;
  left: 29px;
  width: 6px;
  height: 6px;
  z-index: 2;
  border: 1px solid black;
}

.zoom canvas {
  position: absolute;
  display: block;
  top: 0;
  left: 0;
  width: 744px;
  height: 744px;
  image-rendering: -moz-crisp-edges;
  image-rendering: -webkit-crisp-edges;
  image-rendering: pixelated;
  image-rendering: crisp-edges;
}

JavaScript

var img = document.querySelector('.img');
var zoom = document.querySelector('.zoom');
var imgz = document.querySelector('.zoom #can');
window.addEventListener('mousemove', Zoom);

function Zoom(e) {
  zoom.style.transform = `translate(${e.clientX - 37 }px, ${e.clientY - 37}px)`;
  //zoom.style.top = e.clientY - 25 + 'px';
  //zoom.style.left = e.clientX - 25 + 'px';
  imgz.style.transform = `translate(${-((e.clientX) * 6)}px, ${-((e.clientY) * 6)}px)`;
  //imgz.style.top = -((e.clientY) * 5) + 'px';
  //imgz.style.left = -((e.clientX) * 5) + 'px';
}

var ctx = document.getElementById('can').getContext('2d');
var image = new Image();
image.onload = function() {
  ctx.drawImage(image, 0, 0, 124, 124);
}
image.src = '//www.gravatar.com/avatar/e94f2d3d00aeb7532d8ab431e615792b/?default=&s=124';