Create A Custom Pdf Viewer With Javascript

4 min read Jun 22, 2024

Create a Custom PDF Viewer with JavaScript

Creating a custom PDF viewer using JavaScript allows you to build a tailored experience for your users. You can control how the PDF is displayed, add interactive elements, and integrate it seamlessly with your web application. This article will guide you through the basic steps involved in building a custom PDF viewer using the PDF.js library.

1. Set up the Project

Create a new HTML file and include the PDF.js library:




  
  
  Custom PDF Viewer

Create a JavaScript file (script.js) where you will write the code for your viewer.

2. Load the PDF File

In your script.js, use the PDF.js library to load the PDF file you want to display:

const pdfViewer = document.getElementById("pdfViewer");

// Load the PDF file
PDFJS.getDocument({ url: 'your_pdf_file.pdf' }).then(pdf => {
  // Handle the loaded PDF
  console.log(`PDF loaded: ${pdf.numPages} pages`);

  // Render the first page
  renderPage(pdf, 1);
});

// Function to render a specific page
function renderPage(pdf, pageNumber) {
  pdf.getPage(pageNumber).then(page => {
    const viewport = page.getViewport({ scale: 1 });

    // Create a canvas element
    const canvas = document.createElement('canvas');
    const context = canvas.getContext('2d');
    canvas.width = viewport.width;
    canvas.height = viewport.height;

    // Render the page on the canvas
    page.render({
      canvasContext: context,
      viewport: viewport
    }).promise.then(() => {
      pdfViewer.appendChild(canvas);
    });
  });
}

This code will load the PDF file, display the number of pages, and render the first page on the canvas.

3. Navigation and Control

Implement navigation features like page turning, zooming, and scrolling.

// Example for next page button
const nextButton = document.createElement('button');
nextButton.textContent = 'Next Page';
nextButton.addEventListener('click', () => {
  // Increment page number and render the next page
  currentPage++;
  renderPage(pdf, currentPage);
});
pdfViewer.appendChild(nextButton);

Implement other features like downloading the PDF, printing, or searching.

4. Customize the Viewer

Add styling to customize the appearance of the viewer. Use CSS to control the size, color, and layout of the elements.
Add interactive elements like annotations or bookmarks to enhance the user experience.
Consider adding features like search, thumbnails, and page outlining for a more robust viewer.

5. Advanced Features

Use the PDF.js library's features to:
- Extract text from the PDF for searching and highlighting.
- Get annotations and other metadata from the PDF.
- Implement advanced features like form filling and signing.

Conclusion

By following these steps, you can create a custom PDF viewer that meets your specific needs. Remember to explore the capabilities of PDF.js to add features that enhance the user experience and make your viewer more robust.

Create A Custom Pdf Viewer With Javascript