Convert Image to Base64 Data URI

C
Published in: Javascript

In Spreadsheet Paintings, you upload a photograph from the local disk and it transforms the picture into pixel art. Internally, the JavaScript resizes the image using the HTML5 Canvas API and then uploads the base64-encoded representation of the canvas data to the Google Script using the HTMLService where the pixels are converted into RGB colors.

<input type="file" id="image" />
<canvas></canvas>
<script>
  $("document").ready(function () {
    $("input[type=file]").on("change", function (f) {
      var file = f.target.files[0];
      if (file) {
        var reader = new FileReader();
        var image = new Image();
        reader.onload = function (e) {
          image.src = e.target.result;
          var canvas = $("canvas")[0];
          canvas.height = image.height;
          canvas.width = image.width;
          var ctx = canvas.getContext("2d");
          ctx.drawImage(image, 0, 0);
          var dataURL = canvas.toDataURL("image/png");
          console.log(dataURL);
        };
        reader.readAsDataURL(file);
      }
    });
  });
</script>
📮  Subscribe to our Email Newsletter for Google tips and tutorials!
Published in: Javascript

Looking for something? Find here!

Meet the Author

Web Geek, Google Developer Expert
A
Amit Agarwal

Amit Agarwal is a Google Developer Expert in Google Workspace and Google Apps Script. He holds an engineering degree in Computer Science (I.I.T.) and is the first professional blogger in India. He is the developer of Mail Merge for Gmail and Document Studio. Read more on Lifehacker and YourStory

Get in touch

Google Add-ons

Do more with your Gmail and GSuite account
G

We build bespoke solutions that use the capabilities and the features of Google Workspace for automating business processes and driving work productivity.

  1. Mail Merge with Attachments
    Send personalized email to your Google Contact with a Google Sheet and Gmail
  2. Save Emails and Attachments
    Download email messages and file attachments from Gmail to your Google Drive
  3. Google Forms Email Notifications
    Send email notifications to multiple people when a new Google Form is submitted
  4. Document Studio
    Create beautiful pixel perfect documents merging data from Google Sheets and Google Forms
  5. Creator Studio for Google Slides
    Turn your Google Slides presentations into animated GIFs and videos for uploading to YouTube