Favicon.js is a lightweight library that allows you to create ICO and PNG formatted favicons from a canvas element.

Generate an ICO file from a <canvas> element. Initialize a Favicon.Ico object with a canvas element. The canvas should be square for best results. Pass the generate method an array of sizes that the (layered) ICO file should contain.

const ico = new Favicon.Ico(canvas);
const dataurl = ico.generate([16, 32, 48]);

Generate a PNG file from a canvas element. Initialize a Favicon.Png object with a canvas element. The canvas should be square for best results. Pass the generate method the size that should be generated.

const png = new Favicon.Png(canvas);
const dataurl = png.generate(32);

Generate multiple favicon format based on current best practices. Pass Favicon.Package a canvas element and it will return a dictionary of dataurls.

var package = Favicon.Package(canvas);

The package will contain the follow keys which map to common favicon formats.

• ico - favicon.ico
• png16 - favicon-16x16.png
• png32 - favicon-32x32.png
• png180 - apple-touch-icon.png
• png192 - android-chrome-192x192.png
• png512 - android-chrome-512x512.png

The example below will generate an ICO formatted favicon that includes 3 sizes: 16x16, 32x32, and 48x48 pixels. The full example can be found here.

// Setup canvas
const canvas = document.getElementById("canvas");
canvas.width = 128;
canvas.height = 128;
const context = canvas.getContext("2d");

// Draw background
context.fillStyle = "#d85537";
context.fillRect(0, 0, canvas.width, canvas.height);

// Draw text
context.fillStyle = "#FFFFFF";
context.font = "100px Helvetica";
context.textBaseline = "middle";
context.textAlign = "center";
const x = canvas.width / 2;
const y = canvas.height / 2;
context.fillText("F", x, y);

// Create favicon.ico dataurl
const ico = new Favicon.Ico(canvas);
const dataurl = ico.generate([16, 32, 48]);

// Activate the download button
const download = document.getElementById("download");
download.href = dataurl;
download.setAttribute("download", "favicon.ico");