How to Convert an Image URL to Base64 Using Javascript?

Converting an Image URL to Base64

In web development scenarios, it's often necessary to send images for processing or storage without having access to the actual image file. To facilitate this, we can convert image URLs to Base64 format, allowing for efficient transmission.

In your specific case, you have the URL of an image (e.g., "https://example.com/image.png") obtained from a user's input. To convert it to Base64 using JavaScript:

1. Create a new image element: This image element will serve as a temporary representation of the image for processing.

<code class="javascript">const img = new Image();
img.src = imageUrl; // Replace imageUrl with the URL you obtained</code>

2. Draw the image on a canvas: This step creates a pixel-perfect copy of the image on the canvas.

<code class="javascript">const canvas = document.createElement("canvas");
const ctx = canvas.getContext("2d");
canvas.width = img.width;
canvas.height = img.height;
ctx.drawImage(img, 0, 0, img.width, img.height);</code>

3. Convert canvas to Base64: Use the toDataURL() method to convert the canvas into a Base64-encoded string.

<code class="javascript">const base64Image = canvas.toDataURL("image/png");</code>

4. Remove the data URI prefix: The toDataURL() method returns a data URI that includes extra information. Remove the prefix with a regular expression to get the pure Base64 data.

<code class="javascript">const regex = /^data:image\/[A-z]*;base64,/;
const base64Data = base64Image.replace(regex, "");</code>

Now, base64Data contains the Base64-encoded representation of the image. You can transfer this string to your webservice for further processing or save it locally on your system.

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