How To Know If Pdf Js Has Finished Rendering

Have you ever found yourself in a situation where you need to know when a PDF file has finished rendering using PDF.js in your web application? In this article, we'll walk you through how you can detect this crucial event with ease.

PDF.js is a popular JavaScript library that allows you to render PDF files directly in the browser without the need for any external plugins. It's lightweight, easy to use, and provides a seamless experience for viewing PDF documents on the web.

To determine when a PDF file has finished rendering with PDF.js, you can take advantage of the `pagesLoaded` event provided by the library. This event is triggered when all the pages of the PDF file have been successfully loaded and rendered on the screen.

Here's a step-by-step guide on how to implement this in your code:

Firstly, make sure you have included the PDF.js library in your project. You can either download the library and host it locally or use a CDN link to include it in your HTML file.

Next, you need to initialize the PDF viewer and load the PDF file that you want to render. You can do this by creating a `PDFJS.getDocument` instance and passing the URL of the PDF file as a parameter.

PDFJS.getDocument('path/to/your/pdf/file.pdf').promise.then(pdf => {
  pdf.getPage(1); // Load any page to trigger rendering
  pdf.promise.then(() => {
    // All pages have loaded
    console.log('PDF rendering complete!');
  });
});

In the code snippet above, we first load the PDF file using `PDFJS.getDocument` and then call `pdf.getPage(1)` to trigger the rendering process. We then use the `pdf.promise` to wait for all the pages to finish rendering.

Once the `pdf.promise` is fulfilled, you can be confident that the PDF file has finished rendering. You can then perform any additional actions or updates to your UI based on this event.

It's important to note that the `pdf.promise` will only resolve once all pages have been rendered, so you can rely on this event to determine when the rendering process is complete.

In conclusion, detecting when a PDF file has finished rendering with PDF.js is a straightforward process by utilizing the `pagesLoaded` event. By following the steps outlined in this article, you can easily incorporate this functionality into your web application and provide a seamless user experience when working with PDF documents.

We hope this guide has been helpful to you in understanding how to know if PDF.js has finished rendering. Remember to experiment with the code and tailor it to your specific needs. Happy coding!