Flatten Form Showcase Demo Code Sample

Requirements

These packages are required to use these features in production. Trial keys have unlimited access to all features

Web SDKLive demo

Easily enable annotation and form flattening capabilities to permanently merge annotations with page content.

This demo allows you to:

• Annotate a PDF
• Edit fields
• Merge fields and annotations into the page content
• Download the updated PDF

Implementation steps

To add annotation and form flattening capabilities to WebViewer: Step 1: Get stared in your preferred web stack for WebViewer Step 2: Add the ES6 JavaScript sample code provided in this guide

Once you generate your license key, it will automatically be included in your sample code below.

// ES6 Compliant Syntax
// GitHub Copilot v1.0 - GPT-4 Model - July 15, 2025
// File: index.js

import WebViewer from '@pdftron/webviewer';

const licenseKey = 'YOUR_WEBVIEWER_LICENSE_KEY';

// Customize the WebViewer UI
// Add custom buttons for flattening forms and downloading PDFs
const customizeUI = (instance) => {
  const { UI } = instance;

  // Flattening button
  const flattenButton = new UI.Components.CustomButton({
    dataElement: 'flattenButton',
    className: 'custom-button-class',
    label: 'Flattening',
    onClick: () => flatten(instance), // Flatten the document
    style: {
      padding: '10px 20px',
      backgroundColor: 'white',
      color: 'blue',
      border: '1px solid blue',
    }
  });

  // Download button
  const downloadButton = new UI.Components.CustomButton({
    dataElement: 'downloadPdfButton',
    className: 'custom-button-class',
    label: 'Download',
    onClick: () => download(instance), // Download with annotations
    style: {
      padding: '10px 20px',
      backgroundColor: 'blue',
      color: 'white',
    }
  });

  const defaultHeader = UI.getModularHeader('default-top-header');
  defaultHeader.setItems([...defaultHeader.items, flattenButton, downloadButton]);
};

// Flatten the form fields in the PDF document
const flatten = async (instance) => {
  const { documentViewer, PDFNet, annotationManager } = instance.Core;

  await PDFNet.initialize();
  const doc = await documentViewer.getDocument().getPDFDoc();
  const annotations = await annotationManager.exportAnnotations();

  // Run PDFNet methods with memory management
  await PDFNet.runWithCleanup(async () => {

    // lock the document before a write operation
    // runWithCleanup will auto unlock when complete
    doc.lock();

    // import annotations to PDFNet
    const fdf_doc = await PDFNet.FDFDoc.createFromXFDF(annotations);
    await doc.fdfUpdate(fdf_doc);

    // Generate appearances in a way that supports non-standard rotation
    const options = await PDFNet.PDFDoc.createRefreshOptions();
    options.setUseNonStandardRotation(true);
    await doc.refreshAnnotAppearances(options);

    // flatten all annotations in the document
    await doc.flattenAnnotations();

    // clear the original annotations
    annotationManager.deleteAnnotations(annotationManager.getAnnotationsList());
  });

  // clear the cache (rendered) data with the newly updated document
  documentViewer.refreshAll();

  // Update viewer to render with the new document
  documentViewer.updateView();

  // Refresh searchable and selectable text data with the new document
  documentViewer.getDocument().refreshTextData();
};

// Download the PDF
const download = async (instance) => {

  // Set the options for downloading the PDF
  const options = {
    flags: instance.Core.SaveOptions.LINEARIZED,
    downloadType: 'pdf'
  };

  instance.UI.downloadPdf(options);
};

WebViewer(
  {
    path: '/lib',
    initialDoc: 'https://apryse.s3.us-west-1.amazonaws.com/public/files/samples/form.pdf',
    fullAPI: true,
    enableFilePicker: true, // Enable file picker to open files. In WebViewer -> menu icon -> Open File
    licenseKey: licenseKey, 
  },
  document.getElementById('viewer')
).then((instance) => {

  // customize WebViewer UI
  customizeUI(instance);

  console.log('✅ WebViewer loaded successfully.');
}).catch((error) => {
  console.error('❌ Failed to initialize WebViewer:', error);
});

View the full sample on GitHub