How to build a JavaScript image viewer with Viewer.js

Hulya Masharipov

Updated: July 8, 2024

How to build a JavaScript image viewer with Viewer.js

In a world that’s increasingly becoming digital, the ability to display images is fundamental to any web application. So too is learning to build and integrate an image viewer.

This post provides you with a step-by-step guide outlining how to build a JavaScript image viewer with the Viewer.js(opens in a new tab) library.

The first part will walk through how to render and customize an image viewer in the browser with Viewer.js. The second part will look at how to build a fully featured image viewer with the Nutrient image viewer library. Our image viewer library provides some additional benefits, including:

A prebuilt and polished UI for an improved user experience
15+ prebuilt annotation tools to enable document collaboration
Browser-based text editing, page cropping, merging, rotating, and more
Support for more file types with client-side PDF, MS Office, and image viewing
Dedicated support from engineers to speed up integration

Viewer.js a JavaScript image viewer library that lets you render and view image documents in a web browser. It gives you the ability to zoom in and out, rotate, and flip images. It also supports keyboard shortcuts for navigating through images.

Installing Viewer.js

You can install Viewer.js as an npm package(opens in a new tab) or via a CDN from cdnjs(opens in a new tab).

A CDN is a content delivery network or a server that hosts libraries, like Bootstrap.

In this tutorial, you’ll use the CDN method. Copy the JavaScript and CSS files from the CDN(opens in a new tab).

Create a blank index.html file and paste the following:

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta
      name="viewport"
      content="width=device-width, initial-scale=1.0"
    />
    <title>Viewer.js</title>

    <script
      src="https://cdnjs.cloudflare.com/ajax/libs/viewerjs/1.10.5/viewer.min.js"
      integrity="sha512-i5q29evO2Z4FHGCO+d5VLrwgre/l+vaud5qsVqQbPXvHmD9obORDrPIGFpP2+ep+HY+z41kAmVFRHqQAjSROmA=="
      crossorigin="anonymous"
      referrerpolicy="no-referrer"
    ></script>
    <link
      rel="stylesheet"
      href="https://cdnjs.cloudflare.com/ajax/libs/viewerjs/1.10.5/viewer.css"
      integrity="sha512-c7kgo7PyRiLnl7mPdTDaH0dUhJMpij4aXRMOHmXaFCu96jInpKc8sZ2U6lby3+mOpLSSlAndRtH6dIonO9qVEQ=="
      crossorigin="anonymous"
      referrerpolicy="no-referrer"
    />
  </head>
</html>

Creating the markup

Now, create a container div for an image gallery and create a list for the images:

<body>
  <div id="gallery">
    <ul class="images">
      <li>
        <img src="image-1.png" alt="blue background" />
      </li>
      <li>
        <img src="image-2.png" alt="gray background" />
      </li>
      <li>
        <img src="image-3.png" alt="black background" />
      </li>
      <li>
        <img src="image-4.png" alt="green background" />
      </li>
      <li>
        <img src="image-5.png" alt="red background" />
      </li>
      <li>
        <img src="image-6.jpeg" alt="pink background" />
      </li>
    </ul>
  </div>
  <script src="script.js"></script>
</body>

You can now interact with the viewer library. Create a script.js file and add the following code:

const gallery = document.getElementById('gallery');
const viewer = new Viewer(gallery);

Here, you accessed the gallery container and created a new instance of the Viewer class, which enables you to start interacting with the viewer library.

Launching the website locally

Use the Visual Studio Code Live Server extension(opens in a new tab) to serve your website. Right-click the HTML file and choose the Open with Live Server option from the context menu.

live server screenshot

Serving the website locally

Another option is to use the serve(opens in a new tab) package as a simple HTTP server. If you want to use that option, follow the steps below.

Install the serve package:

npm install --global serve

Serve the contents of the current directory:

serve -l 8080 .

Navigate to http://localhost:8080 to view the website.

You can customize the toolbar by passing options to your viewer instance. You can view all the toolbar options in the Viewer.js documentation(opens in a new tab):

const viewer = new Viewer(gallery, { options });

For the custom toolbar, use the following options:

const gallery = document.getElementById('gallery');
const viewer = new Viewer(gallery, {
  // Custom toolbar.
  toolbar: {
    oneToOne: true,

    prev() {
      viewer.prev(true);
    },

    play: true,

    next() {
      viewer.next(true);
    },

    download() {
      const a = document.createElement('a');

      a.href = viewer.image.src;
      a.download = viewer.image.alt;
      document.body.appendChild(a);
      a.click();
      document.body.removeChild(a);
    },
  },
});

Setting oneToOne to true shows the aspect ratio of the image.
The prev and next functions show the previous and next image.
The play function shows the image in fullscreen mode.
The download option helps you download the image.

Nutrient JavaScript image viewer

We offer a commercial JavaScript image viewer library that can easily be integrated into your web application. Our JavaScript viewer supports rendering JPEG, PNG, TIFF, and PDF files in any modern browser and on any mobile device without any plugins.

Example of our JavaScript image viewer

To see our image viewer in action, upload a JPG, PNG, or TIFF file by selecting Choose Example > Standalone > Open Document. Once your image is displayed in the viewer, you can try drawing freehand, adding a note, or applying a crop or an eSignature.

Requirements to get started

The latest stable version of Node.js(opens in a new tab).
A package manager compatible with npm(opens in a new tab). This guide contains usage examples for Yarn(opens in a new tab) and the npm client(opens in a new tab) (installed with Node.js by default).

Adding Nutrient to your project

Install the @nutrient-sdk/viewer package from npm. If you prefer, you can also download the Nutrient Web SDK manually:

npm i @nutrient-sdk/viewer

pnpm add @nutrient-sdk/viewer

yarn add @nutrient-sdk/viewer

To make the Nutrient Web SDK work, copy the required library artifacts to your assets directory:

cp -R ./node_modules/@nutrient-sdk/viewer/dist/ ./assets/

Make sure your assets folder includes:

nutrient-viewer.js
A nutrient-viewer-lib/ directory containing the runtime dependencies

Integrating into your project

Add the image you want to display to your project directory. You can use our demo image as an example.
Add a <div> where the Nutrient viewer will be mounted:

<div id="nutrient" style="height: 100vh;"></div>

Include nutrient-viewer.js in your HTML:

import './assets/nutrient-viewer.js';

Initialize the Nutrient viewer by calling NutrientViewer.load():

<script type="module">
  import './assets/nutrient-viewer.js';

  const baseUrl = `${window.location.protocol}//${window.location.host}/assets/`;

  NutrientViewer.load({
    container: '#nutrient',
    document: 'image.png', // Path to your image.
    baseUrl,
  })
    .then((instance) => {
      console.log('Nutrient Viewer loaded', instance);
    })
    .catch((error) => {
      console.error(error.message);
    });
</script>

Example index.html file

<!DOCTYPE html>
<html>
  <head>
    <title>Nutrient Image Viewer</title>
    <meta
      name="viewport"
      content="width=device-width, initial-scale=1.0"
    />
  </head>
  <body>
    <div id="nutrient" style="height: 100vh;"></div>

    <script type="module">
      import './assets/nutrient-viewer.js';

      const baseUrl = `${window.location.protocol}//${window.location.host}/assets/`;

      NutrientViewer.load({
        container: '#nutrient',
        document: 'image.png',
        baseUrl,
      })
        .then((instance) => {
          console.log('Nutrient Viewer loaded', instance);
        })
        .catch((error) => {
          console.error(error.message);
        });
    </script>
  </body>
</html>

Resulting page

Adding even more capabilities

Once you’ve deployed your viewer, you can start customizing it to meet your specific requirements or easily add more capabilities. To help you get started, here are some of our most popular JavaScript guides:

Conclusion

In this article, you first learned how to build an image viewer with the Viewer.js library. In the second part, you walked through how to create an image viewer with Nutrient Web SDK. If you hit any snags, don’t hesitate to reach out to our Support team for help.

At Nutrient, we offer a commercial, feature-rich, and completely customizable JavaScript image viewer library that’s easy to integrate and comes with well-documented APIs to handle advanced use cases. Try it for free, or visit our demo to see it in action.

FAQ

What is Viewer.js?

Viewer.js is a JavaScript library for displaying and interacting with images in a web browser, offering features like zooming, rotating, and navigating images.

How do I install Viewer.js?

You can install Viewer.js using npm, or include it via a CDN.

What are the steps to create an image viewer with Viewer.js?

Install Viewer.js, set up your HTML structure, and initialize the viewer instance using JavaScript.

Can I customize the toolbar in Viewer.js?

Yes. You can customize the toolbar by passing options to the viewer instance when initializing it.

What additional features does Nutrient offer over Viewer.js?

Nutrient provides a comprehensive solution with additional features like a polished UI, annotation tools, and support for various file types.

How do I integrate Nutrient into my project?

Install Nutrient via npm, copy the necessary files, and initialize it using PSPDFKit.load() in your JavaScript.

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