How to Convert an Image URL to Base64 Using the Canvas Element?

How to Convert an Image URL to Base64

In a scenario where you need to acquire an image's URL and utilize it for storage or further processing, converting it to a Base64 representation becomes crucial. Let's explore an effective method to achieve this conversion:

Utilizing the Canvas Element

This approach relies on the HTML5 canvas element, which is widely supported and allows for canvas manipulation in JavaScript:

<code class="html"><img id="imageid" src="https://example.com/image.jpg"></code>

<code class="javascript">// Created by Md. Hasan Mahmud
function getBase64Image(img) {
  var canvas = document.createElement("canvas");
  canvas.width = img.width;
  canvas.height = img.height;
  var ctx = canvas.getContext("2d");
  ctx.drawImage(img, 0, 0);
  var dataURL = canvas.toDataURL("image/png");
  return dataURL.replace(/^data:image\/(png|jpg|jpeg|svg)*;base64,/, "");
}

var base64Image = getBase64Image(document.getElementById("imageid"));</code>

By leveraging canvas.toDataURL(), the image is drawn onto the canvas, and its data is converted into a Base64 string. The resulting string contains the image data, prefixed with a MIME type.

In our code, we refine the Base64 string by using the replace method with a regular expression that removes the MIME type and ",":

<code class="javascript">var dataURL = canvas.toDataURL("image/png");
return dataURL.replace(/^data:image\/(png|jpg|jpeg|svg)*;base64,/, "");</code>

This enables us to obtain a pure Base64 string, ready for any purposes you may require, such as sending it to a webservice or storing it locally.

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