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How to Render PDF Files Within Your Application Using Accusoft PDF Viewer

Today’s developers have many options available to them when they need to render PDF files within their applications. However, not all of those solutions offer the same level of rendering quality or ease of integration. Accusoft PDF Viewer leverages HTML5 PDF techniques pioneered by PDF.js to provide a better way to render PDF files and manage them within a secure application environment.

The Challenges of Web-Based PDF Rendering

Until the development of PDF.js in 2011, developers typically relied upon external PDF viewers and browser plug-ins to open and render PDFs. The key benefit of these solutions is that they allowed PDFs to be viewed natively with whatever proprietary rendering technology the software utilized. Since older browsers lacked the ability to render data from PDF files as HTML elements, this was the only option available for many years.

There are two significant problems with this approach, however. The first challenge has to do with security. Browser plug-ins are notoriously vulnerable to code-injection cyberattacks, making them an unattractive option for developers looking to keep their web applications secure. Relying on external PDF viewers also creates a potentially disjointed user experience, either forcing someone to download a file and view it separately or view it within a plug-in that may utilize an unfamiliar interface.

Rendering PDF in HTML5 with Accusoft PDF Viewer

Fortunately, developers can avoid these problems by integrating a PDF.js-based viewer directly into their web applications. Accusoft PDF Viewer builds upon the capabilities of the PDF.js library to deliver superior rendering performance while maintaining an incredibly small footprint. It gets up and running with just a few lines of code, without any of the complicated server configurations that often slow down the deployment of web-based viewing solutions.

To understand how Accusoft PDF Viewer renders PDFs, it’s helpful to look at how the multiple layers of PDF.js function:

  • Core Layer: This is the heart of the PDF.js library. The core layer is responsible for interpreting and parsing the binary format of PDF data so it can be rendered accurately.
  • Display Layer: An interface for rendering the contents of the PDF, this API is responsible for converting parsed PDF data into an HTML5 canvas element.
  • Viewer Layer: This is the direct interface that allows users to interact with the displayed PDF. Although PDF.js provides some rudimentary viewing functions, Accusoft PDF Viewer substitutes its own viewing layer to offer responsive viewing controls for all screen sizes.

When Accusoft PDF Viewer opens a PDF, the core layer reads and interprets the file contents before passing that information along to the display layer. The incoming data is then rendered onto a HTML5 canvas element using JavaScript, providing all the graphics models, shapes, text, images, and objects necessary to display each page through the viewer layer. 

Of course, displaying PDFs as static images wouldn’t be very useful for applications that need to display text-based documents. That’s why the viewer also creates a separate HTML text overlay that allows users to select, copy/paste, and search text. Accusoft PDF Viewer has been optimized for text search performance, allowing it to rapidly search even larger, text-heavy documents.

Delivering High-Quality Rendering Performance

Although PDF.js can render most basic PDF files without much difficulty, it requires substantial development work to support modern high-resolution displays and mobile devices. Accusoft PDF Viewer leverages decades of experience with imaging technology to deliver a responsive, high-quality viewing experience across all screen types.

Many of today’s web-based applications need to be able to render PDFs accurately on high-resolution screens like Apple’s Retina displays or other 4k monitors and laptops. Accusoft PDF Viewer not only supports these displays, but also maintains high-resolution rendering at multiple zoom levels without impacting performance. Many viewers downgrade resolution at higher zoom levels due to memory issues. Thanks to its optimized HTML5 rendering, Accusoft PDF Viewer can manipulate high-quality PDF images right out of the box without having to draw upon additional processing resources.

Responsible Mobile Device Support

While rendering to mobile devices isn’t particularly challenging for a PDF.js viewer, providing a quality viewing experience on mobile screens does pose some difficulties. The main issue here isn’t with rendering, but rather with the user interface. Mobile viewing calls for specialized UI elements that support touch-based interactions like pinch to zoom. Accommodating this need is critical for developers because so many people are accessing web-based applications using their mobile devices.

Accusoft PDF Viewer’s responsive viewing layer adjusts to mobile devices by providing specialized UI controls when it renders to a mobile display. This ensures that anyone using the application’s built-in viewer will be able to interact with PDFs easily regardless of the device they’re using to access it. Without this support, developers would have to build features like pinch-to-zoom from scratch as the browser’s implementation wouldn’t carry over to the viewer’s implementation. This might sound like a mild inconvenience, but users may have a hard time interacting with the application on mobile devices without intuitive touchscreen controls.

Adding Markup Tools

One of the limitations of the original PDF.js library is the complete lack of annotation support. This wasn’t a huge issue when it originally debuted, but most users expect web applications to support features like annotation and eSignature. Building a completely new viewer layer made it possible to incorporate multiple annotation markup tools in the Professional Version of Accusoft PDF Viewer without having to rely on external server dependencies that are so frequently required for annotations. The same viewer layer could also support eSignatures and made it easy to incorporate customization features that allow developers to quickly alter the UI and reshape the viewing experience.

Experience Accusoft PDF Viewer’s Rendering

A 100% client-side integration, Accusoft PDF Viewer can be incorporated quickly and easily into any web-based application. This JavaScript solution is the easiest way for developers to add high-quality PDF rendering to their software projects without sacrificing control or performance. And thanks to its out-of-the-box mobile support, it also helps developers to create a consistent viewing experience across all device types.

To see what Accusoft PDF Viewer can do for your application, download the Standard Version today at no cost and start using it within your application environment. Just a few lines of code is all you need to get started! For expanded functionality like annotations and UI customization, consider upgrading to Professional Edition, which provides even more features within the same lightweight SDK integration.