HTML5 Canvas Loading Progress Bar Animation

Crop Image in Canvas Using JavaScript
Code Snippet:html5 canvas loader
Author: Lennart Hase
Published: January 18, 2024
Last Updated: January 22, 2024
Downloads: 287
License: MIT
Edit Code online: View on CodePen
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The code snippet helps you to create a loading progress bar animation on HTML5 canvas. It visualizes progress dynamically. A progress bar fills as content loads, offering a visual loading indicator.

Apply this code in web projects to enhance user experience during content loading on a canvas. Benefit: Provides a visually engaging loading indication for a smoother user interaction.

How to Create HTML5 Canvas Loading Progress Bar Animation

1. First of all, create an HTML file. Add the necessary HTML structure. Include a <canvas></canvas> tag.

<canvas></canvas>

2. Integrate the given CSS code within <style> tags or link an external CSS file. Adjust the canvas position and layout as per your page requirements.

body{
  margin: 0;
  padding: 0;
  background: #272822;
}

canvas{
  position: absolute;
  top: calc(50% - 50px);
  top: -webkit-calc(50% - 100px);
  left: calc(50% - 200px);
  left: -webkit-calc(50% - 200px);
}

3. Load the jQuery JavaScript library by adding the following CDN link just before closing the <body> element:

<script src='https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js'></script>

4. Finally, include the following JavaScript code in a <script> tag or link an external JS file. This code initializes and manages the loading progress animation.

Adjust variables like particle_no to change the number of particles in the animation. Modify colors, dimensions, or animation behavior according to your design preferences.

particle_no = 25;

window.requestAnimFrame = (function() {
  return window.requestAnimationFrame ||
    window.webkitRequestAnimationFrame ||
    window.mozRequestAnimationFrame ||
    window.oRequestAnimationFrame ||
    window.msRequestAnimationFrame ||
    function(callback) {
      window.setTimeout(callback, 1000 / 60);
    };
})();

var canvas = document.getElementsByTagName("canvas")[0];
var ctx = canvas.getContext("2d");

var counter = 0;
var particles = [];
var w = 400,
  h = 200;
canvas.width = w;
canvas.height = h;

function reset() {
  ctx.fillStyle = "#272822";
  ctx.fillRect(0, 0, w, h);

  ctx.fillStyle = "#171814";
  ctx.fillRect(25, 80, 350, 25);
}

function progressbar() {
  this.widths = 0;
  this.hue = 0;

  this.draw = function() {
    ctx.fillStyle = 'hsla(' + this.hue + ', 100%, 40%, 1)';
    ctx.fillRect(25, 80, this.widths, 25);
    var grad = ctx.createLinearGradient(0, 0, 0, 130);
    grad.addColorStop(0, "transparent");
    grad.addColorStop(1, "rgba(0,0,0,0.5)");
    ctx.fillStyle = grad;
    ctx.fillRect(25, 80, this.widths, 25);
  }
}

function particle() {
  this.x = 23 + bar.widths;
  this.y = 82;

  this.vx = 0.8 + Math.random() * 1;
  this.v = Math.random() * 5;
  this.g = 1 + Math.random() * 3;
  this.down = false;

  this.draw = function() {
    ctx.fillStyle = 'hsla(' + (bar.hue + 0.3) + ', 100%, 40%, 1)';;
    var size = Math.random() * 2;
    ctx.fillRect(this.x, this.y, size, size);
  }
}

bar = new progressbar();

function draw() {
  reset();
  counter++

  bar.hue += 0.8;

  bar.widths += 2;
  if (bar.widths > 350) {
    if (counter > 215) {
      reset();
      bar.hue = 0;
      bar.widths = 0;
      counter = 0;
      particles = [];
    } else {
      bar.hue = 126;
      bar.widths = 351;
      bar.draw();
    }
  } else {
    bar.draw();
    for (var i = 0; i < particle_no; i += 10) {
      particles.push(new particle());
    }
  }
  update();
}

function update() {
  for (var i = 0; i < particles.length; i++) {
    var p = particles[i];
    p.x -= p.vx;
    if (p.down == true) {
      p.g += 0.1;
      p.y += p.g;
    } else {
      if (p.g < 0) {
        p.down = true;
        p.g += 0.1;
        p.y += p.g;
      } else {
        p.y -= p.g;
        p.g -= 0.1;
      }
    }
    p.draw();
  }
}

function animloop() {
  draw();
  requestAnimFrame(animloop);
}

animloop();

Feel free to customize it to suit your design and enhance the user experience during content loading.

That’s all! hopefully, you have successfully created a Canvas Loading Progress Bar Animation. If you have any questions or suggestions, feel free to comment below.

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