JSFiddle - React, Tailwind, and code Playground

by yacan8

HTML

<canvas id="canvas"></canvas>
<div id="color">
</div>

CSS

#color{
  width: 10px;
  height: 10px;
}

JavaScript

var img = new Image();
img.src = 'https://mdn.mozillademos.org/files/5397/rhino.jpg';
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
img.onload = function() {
  ctx.drawImage(img, 0, 0);
  img.style.display = 'none';
};
var color = document.getElementById('color');
function pick(event) {
  var x = event.layerX;
  var y = event.layerY;
  var pixel = ctx.getImageData(x, y, 1, 1);
  var data = pixel.data;
  var rgba = 'rgba(' + data[0] + ',' + data[1] +
             ',' + data[2] + ',' + (data[3] / 255) + ')';
  color.style.background =  rgba;
  color.textContent = rgba;
}
canvas.addEventListener('mousemove', pick);