I'm trying to create a user interface where clicking a 'Sign' button opens a modal displaying a PDF. I need to add: 1. A button on the signature field of the PDF that, when clicked, displays a signature pad for users to sign 2. An input field on the date field to allow date entry. How can I implement these interactive PDF features in Angular? Are there any recommended open-source libraries or alternative approaches to achieve this functionality?

NeuroAgent

How to Add Interactive PDF Components in Angular

Learn how to add interactive buttons and input fields over PDFs in Angular. Complete guide with code examples for signature pads and date inputs using top PDF viewer libraries.

#angular-forms-pdf #angular-pdf-development #angular-pdf-tutorial #pdf-interactive-components #pdf-overlay-implementation #pdf-viewer-libraries #signature-pad-angular

11/07/2025, 10:53 PM

How to add interactive components like buttons and input fields on top of a PDF in Angular?

I’m trying to create a user interface where clicking a ‘Sign’ button opens a modal displaying a PDF. I need to add:

A button on the signature field of the PDF that, when clicked, displays a signature pad for users to sign
An input field on the date field to allow date entry

How can I implement these interactive PDF features in Angular? Are there any recommended open-source libraries or alternative approaches to achieve this functionality?

NeuroAgent

To add interactive components like buttons and input fields on top of a PDF in Angular, you can use specialized PDF viewer libraries that support form overlays and interactive elements. The most effective approach involves using libraries like ngx-extended-pdf-viewer or Syncfusion PDF Viewer that provide built-in support for interactive forms, or implementing a custom overlay solution with PDF.js combined with Angular components positioned absolutely over the PDF content.

Overview of Approaches
Recommended Libraries for Interactive PDFs
Implementing Signature Functionality
Implementing Date Input Fields
Custom Overlay Implementation
Code Examples and Implementation
Best Practices and Performance Considerations

Overview of Approaches

When implementing interactive components over PDFs in Angular, you have several approaches to consider:

Library-Based Solutions

Most developers choose specialized PDF viewer libraries that provide built-in interactive form support. These libraries handle the complex rendering and interaction logic while allowing you to customize the user interface.

Custom Overlay Solutions

For more specific requirements, you can implement a custom overlay system where you position Angular components (buttons, inputs) absolutely over the PDF content using coordinates and event handling.

Hybrid Approaches

Many projects combine library-based PDF viewing with custom interactive components for specific features like signature pads or date pickers that aren’t fully supported by standard PDF form elements.

The choice depends on your project requirements, budget, and the complexity of interactive features needed.

Recommended Libraries for Interactive PDFs

ngx-extended-pdf-viewer

This library provides comprehensive support for interactive forms with two-way data binding, making it ideal for your use case. It supports:

Standard and XFA forms
Text fields, checkboxes, radio buttons, and dropdowns
Advanced annotation capabilities
Customizable toolbar and UI

According to the npm package documentation, it offers “Comprehensive form support with two-way data binding” and “PDF annotation and editing” features.

Syncfusion PDF Viewer

Syncfusion provides a complete interactive PDF viewer with extensive form support:

Complete interactive forms with text fields, checkboxes, radio buttons, and dropdowns
Real-time editing, preview, and saving of forms
Handwritten signature support
Customizable toolbar and UI

As stated in their product description, it allows you to “Complete interactive forms with text fields, checkboxes, radio buttons, and dropdowns, or design new forms within the viewer.”

PDF.js Express

This commercial solution wraps around the open-source PDF.js rendering engine and provides:

Annotation capabilities
E-signatures
Form filling
Advanced customization options

The PDF.js Express documentation mentions it “offers developers a way to quickly add annotation, e-signatures, and form filling to their Angular PDF viewer.”

ng2-pdf-viewer

A simpler alternative for basic PDF viewing with some interactive features:

PDF text extraction and selection
Basic form field support
Event handling for user interactions

The GitHub repository provides examples of how to implement PDF viewing with Angular components.

Implementing Signature Functionality

Using Built-in Signature Support

Many PDF viewers provide built-in signature functionality. For example, Syncfusion’s PDF viewer supports handwritten signatures through their signature panel:

typescript

import { Component } from '@angular/core';
import { PdfViewerModule } from '@syncfusion/ej2-angular-pdfviewer';
import { ToolbarItem } from '@syncfusion/ej2-pdfviewer';

@Component({
  selector: 'app-signature-example',
  template: `
    <button (click)="activateSignatureTool()">Sign Document</button>
    <ejs-pdfviewer 
      #pdfviewer
      [serviceUrl]='serviceUrl'
      [documentPath]='documentPath'
      [toolbarItems]='toolbarItems'>
    </ejs-pdfviewer>
  `
})
export class SignatureExampleComponent {
  serviceUrl = 'https://services.syncfusion.com/production/js/production/pdfviewer';
  documentPath = 'https://cdn.syncfusion.com/content/pdf/pdf-succinctly.pdf';
  
  toolbarItems: ToolbarItem[] = ['SignatureTool'];
  
  activateSignatureTool() {
    const viewer = document.getElementById('pdfviewer').ej2_instances[0];
    viewer.annotationModule.setAnnotationMode('Signature');
  }
}

Custom Signature Pad Implementation

For more control, you can implement a custom signature pad using canvas and overlay it on the PDF:

typescript

import { Component, ViewChild, ElementRef } from '@angular/core';

@Component({
  selector: 'app-custom-signature',
  template: `
    <div class="pdf-container" #pdfContainer>
      <pdf-viewer [src]="pdfSrc" [render-text]="true"></pdf-viewer>
      <div class="overlay-controls">
        <button (click)="showSignaturePad()">Sign Here</button>
        <div *ngIf="showPad" class="signature-pad">
          <canvas #signatureCanvas width="300" height="150"></canvas>
          <button (click)="clearSignature()">Clear</button>
          <button (click)="saveSignature()">Save</button>
        </div>
      </div>
    </div>
  `,
  styles: [`
    .pdf-container { position: relative; }
    .overlay-controls { position: absolute; top: 100px; left: 50px; }
    .signature-pad { border: 1px solid #ccc; margin-top: 10px; }
  `]
})
export class CustomSignatureComponent {
  @ViewChild('pdfContainer') pdfContainer: ElementRef;
  @ViewChild('signatureCanvas') signatureCanvas: ElementRef;
  
  pdfSrc = 'path/to/your/document.pdf';
  showPad = false;
  isDrawing = false;
  
  showSignaturePad() {
    this.showPad = true;
    this.setupCanvas();
  }
  
  setupCanvas() {
    const canvas = this.signatureCanvas.nativeElement;
    const ctx = canvas.getContext('2d');
    
    canvas.addEventListener('mousedown', (e) => {
      this.isDrawing = true;
      ctx.beginPath();
      ctx.moveTo(e.offsetX, e.offsetY);
    });
    
    canvas.addEventListener('mousemove', (e) => {
      if (!this.isDrawing) return;
      ctx.lineTo(e.offsetX, e.offsetY);
      ctx.stroke();
    });
    
    canvas.addEventListener('mouseup', () => {
      this.isDrawing = false;
    });
  }
  
  clearSignature() {
    const canvas = this.signatureCanvas.nativeElement;
    const ctx = canvas.getContext('2d');
    ctx.clearRect(0, 0, canvas.width, canvas.height);
  }
  
  saveSignature() {
    const canvas = this.signatureCanvas.nativeElement;
    const signatureData = canvas.toDataURL();
    // Here you would typically send this to your PDF processing service
    console.log('Signature saved:', signatureData);
    this.showPad = false;
  }
}

Implementing Date Input Fields

Using PDF Form Fields

The most straightforward approach is to use PDF form fields that are compatible with Angular PDF viewers:

typescript

import { Component } from '@angular/core';

@Component({
  selector: 'app-date-form-example',
  template: `
    <pdf-viewer 
      [src]="pdfSrc"
      [render-text]="true"
      (pageRendered)="onPageRendered($event)">
    </pdf-viewer>
    <div *ngIf="showDateInput" class="date-overlay">
      <input 
        type="date" 
        [(ngModel)]="selectedDate"
        (blur)="onDateBlur()">
    </div>
  `
})
export class DateFormExampleComponent {
  pdfSrc = 'path/to/your/form.pdf';
  showDateInput = false;
  selectedDate: string;
  dateFieldPosition: {x: number, y: number};
  
  onPageRendered(event) {
    // Logic to detect when date fields are rendered
    // and position the overlay input accordingly
  }
  
  onDateBlur() {
    // Save the date to the PDF form field
    this.showDateInput = false;
  }
}

Custom Date Input Overlay

For more control over the date input experience:

typescript

import { Component, ViewChild, ElementRef } from '@angular/core';

@Component({
  selector: 'app-custom-date-input',
  template: `
    <div class="pdf-viewer-container">
      <pdf-viewer [src]="pdfSrc" [render-text]="true"></pdf-viewer>
      <div *ngIf="showDatePicker" class="date-picker-overlay" 
           [style.left]="datePosition.x + 'px'" 
           [style.top]="datePosition.y + 'px'">
        <input type="date" 
               [(ngModel)]="selectedDate"
               (change)="onDateSelect($event)"
               (blur)="hideDatePicker()">
      </div>
    </div>
  `,
  styles: [`
    .pdf-viewer-container { position: relative; }
    .date-picker-overlay { 
      position: absolute; 
      z-index: 1000; 
      background: white;
      border: 1px solid #ccc;
      padding: 5px;
      border-radius: 4px;
    }
  `]
})
export class CustomDateInputComponent {
  @ViewChild('pdfViewer') pdfViewer: ElementRef;
  
  pdfSrc = 'path/to/your/document.pdf';
  showDatePicker = false;
  selectedDate: string;
  datePosition = { x: 0, y: 0 };
  
  showDatePickerAtPosition(x: number, y: number) {
    this.datePosition = { x, y };
    this.showDatePicker = true;
    this.selectedDate = new Date().toISOString().split('T')[0]; // Today's date
  }
  
  onDateSelect(event: any) {
    // Handle date selection and update PDF
    console.log('Date selected:', this.selectedDate);
    // Here you would typically update the PDF form field
  }
  
  hideDatePicker() {
    setTimeout(() => this.showDatePicker = false, 200); // Allow time for blur to complete
  }
}

Custom Overlay Implementation

For maximum flexibility, you can implement a custom overlay system:

typescript

import { Component, ViewChild, ElementRef } from '@angular/core';
import { fromEvent } from 'rxjs';
import { debounceTime } from 'rxjs/operators';

@Component({
  selector: 'app-custom-overlay',
  template: `
    <div class="pdf-container" #pdfContainer>
      <pdf-viewer [src]="pdfSrc" [render-text]="true"></pdf-viewer>
      <div class="interactive-overlay">
        <!-- Signature Button Overlay -->
        <div class="signature-field" 
             [style.left]="signatureField.x + 'px'" 
             [style.top]="signatureField.y + 'px'"
             [style.width]="signatureField.width + 'px'" 
             [style.height]="signatureField.height + 'px'">
          <button (click)="openSignaturePad()">Sign</button>
        </div>
        
        <!-- Date Input Overlay -->
        <div class="date-field" 
             [style.left]="dateField.x + 'px'" 
             [style.top]="dateField.y + 'px'"
             [style.width]="dateField.width + 'px'" 
             [style.height]="dateField.height + 'px'">
          <input *ngIf="showDateInput" 
                 type="date" 
                 [(ngModel)]="selectedDate"
                 (blur)="saveDateInput()">
        </div>
      </div>
    </div>
  `,
  styles: [`
    .pdf-container { position: relative; width: 100%; height: 800px; }
    .interactive-overlay { position: absolute; top: 0; left: 0; width: 100%; height: 100%; pointer-events: none; }
    .signature-field, .date-field { 
      position: absolute; 
      border: 1px dashed #007bff; 
      background: rgba(0, 123, 255, 0.1);
      pointer-events: all;
    }
    .signature-field button { 
      width: 100%; height: 100%; 
      border: none; background: transparent; 
      cursor: pointer; font-size: 12px;
    }
    .signature-field button:hover { background: rgba(0, 123, 255, 0.2); }
  `]
})
export class CustomOverlayComponent {
  @ViewChild('pdfContainer') pdfContainer: ElementRef;
  
  pdfSrc = 'path/to/your/document.pdf';
  showDateInput = false;
  selectedDate: string;
  
  // Define field positions (these would be dynamically set based on PDF analysis)
  signatureField = { x: 100, y: 200, width: 80, height: 30 };
  dateField = { x: 200, y: 250, width: 100, height: 30 };
  
  ngOnInit() {
    // Set up event listeners for PDF interactions
    this.setupFieldInteractions();
  }
  
  setupFieldInteractions() {
    // Logic to detect when users click on PDF areas
    // and determine if they're clicking on signature/date fields
  }
  
  openSignaturePad() {
    // Open signature pad modal or overlay
    console.log('Opening signature pad');
    // Implementation would show a signature canvas
  }
  
  saveDateInput() {
    console.log('Date saved:', this.selectedDate);
    // Logic to save date to PDF document
    this.showDateInput = false;
  }
}

Code Examples and Implementation

Complete Example with ngx-extended-pdf-viewer

Here’s a comprehensive implementation using ngx-extended-pdf-viewer:

typescript

import { Component } from '@angular/core';

@Component({
  selector: 'app-pdf-forms-example',
  template: `
    <div class="pdf-forms-container">
      <ngx-extended-pdf-viewer
        [src]="pdfSrc"
        [useBrowserLocale]="true"
        [height]="'80vh'"
        [textLayer]="true"
        [handTool]="true"
        [stampTool]="true"
        [signatureTool]="true"
        [formElements]="true"
        (pageRendered)="onPageRendered($event)"
        (fieldClick)="onFieldClick($event)">
        
        <!-- Custom toolbar with signature button -->
        <ngx-pdf-toolbar>
          <button class="custom-sign-btn" (click)="openSignaturePad()">
            Sign Document
          </button>
        </ngx-pdf-toolbar>
      </ngx-extended-pdf-viewer>
      
      <!-- Signature Pad Modal -->
      <div *ngIf="showSignatureModal" class="signature-modal">
        <div class="modal-content">
          <h3>Sign Document</h3>
          <canvas #signatureCanvas width="400" height="200"></canvas>
          <div class="modal-buttons">
            <button (click)="clearSignature()">Clear</button>
            <button (click)="saveSignature()">Save Signature</button>
            <button (click)="closeSignatureModal()">Cancel</button>
          </div>
        </div>
      </div>
      
      <!-- Date Picker Overlay -->
      <div *ngIf="showDatePicker" class="date-picker-overlay"
           [style.left]="datePosition.x + 'px'" 
           [style.top]="datePosition.y + 'px'">
        <input type="date" 
               [(ngModel)]="selectedDate"
               (change)="onDateSelect($event)"
               (blur)="hideDatePicker()">
      </div>
    </div>
  `,
  styles: [`
    .pdf-forms-container { position: relative; }
    .custom-sign-btn { 
      background: #007bff; 
      color: white; 
      border: none; 
      padding: 5px 10px; 
      border-radius: 3px;
      cursor: pointer;
    }
    .signature-modal { 
      position: fixed; 
      top: 0; left: 0; 
      width: 100%; height: 100%; 
      background: rgba(0,0,0,0.5); 
      display: flex; 
      justify-content: center; 
      align-items: center;
      z-index: 1000;
    }
    .modal-content { 
      background: white; 
      padding: 20px; 
      border-radius: 8px;
      text-align: center;
    }
    .modal-buttons { 
      margin-top: 15px; 
    }
    .modal-buttons button { 
      margin: 0 5px; 
      padding: 5px 10px;
    }
    .date-picker-overlay { 
      position: absolute; 
      z-index: 100; 
      background: white;
      border: 1px solid #ccc;
      padding: 5px;
      border-radius: 4px;
    }
  `]
})
export class PdfFormsExampleComponent {
  pdfSrc = 'path/to/your/interactive-form.pdf';
  showSignatureModal = false;
  showDatePicker = false;
  selectedDate: string;
  datePosition = { x: 0, y: 0 };
  
  @ViewChild('signatureCanvas') signatureCanvas: any;
  
  onPageRendered(event: any) {
    // Logic to handle when PDF pages are rendered
    // Could set up field detection here
  }
  
  onFieldClick(event: any) {
    // Handle clicks on PDF form fields
    if (event.field && event.field.type === 'signature') {
      this.openSignaturePad();
    } else if (event.field && event.field.type === 'text') {
      // Check if it's a date field
      if (event.field.name.toLowerCase().includes('date')) {
        this.showDateAtPosition(event.x, event.y);
      }
    }
  }
  
  openSignaturePad() {
    this.showSignatureModal = true;
    this.setupSignatureCanvas();
  }
  
  setupSignatureCanvas() {
    const canvas = this.signatureCanvas.nativeElement;
    const ctx = canvas.getContext('2d');
    let isDrawing = false;
    
    const startDrawing = (e: any) => {
      isDrawing = true;
      ctx.beginPath();
      ctx.moveTo(e.offsetX, e.offsetY);
    };
    
    const draw = (e: any) => {
      if (!isDrawing) return;
      ctx.lineTo(e.offsetX, e.offsetY);
      ctx.stroke();
    };
    
    const stopDrawing = () => {
      isDrawing = false;
    };
    
    canvas.addEventListener('mousedown', startDrawing);
    canvas.addEventListener('mousemove', draw);
    canvas.addEventListener('mouseup', stopDrawing);
  }
  
  clearSignature() {
    const canvas = this.signatureCanvas.nativeElement;
    const ctx = canvas.getContext('2d');
    ctx.clearRect(0, 0, canvas.width, canvas.height);
  }
  
  saveSignature() {
    const canvas = this.signatureCanvas.nativeElement;
    const signatureData = canvas.toDataURL();
    // Here you would save the signature to the PDF
    console.log('Signature saved:', signatureData);
    this.closeSignatureModal();
  }
  
  closeSignatureModal() {
    this.showSignatureModal = false;
  }
  
  showDateAtPosition(x: number, y: number) {
    this.datePosition = { x, y };
    this.showDatePicker = true;
    this.selectedDate = new Date().toISOString().split('T')[0];
  }
  
  onDateSelect(event: any) {
    console.log('Date selected:', this.selectedDate);
    // Logic to update PDF form field
  }
  
  hideDatePicker() {
    setTimeout(() => this.showDatePicker = false, 200);
  }
}

Best Practices and Performance Considerations

Performance Optimization

Lazy Loading: Load PDF viewer modules only when needed to reduce initial bundle size.
Canvas Optimization: For signature pads, implement proper canvas cleanup and memory management.
Event Debouncing: Use debouncing for PDF interaction events to prevent performance issues.
Virtual Scrolling: For large PDFs, implement virtual scrolling to handle many pages efficiently.

Accessibility Considerations

Keyboard Navigation: Ensure all interactive components are keyboard accessible.
Screen Reader Support: Provide proper ARIA labels and descriptions for form elements.
Focus Management: Manage focus properly when showing/hiding modals and overlays.

Security Considerations

Input Validation: Validate all user inputs, especially for date fields and signature data.
File Handling: Securely handle PDF uploads and downloads.
Data Sanitization: Sanitize signature data and other user inputs before processing.

Implementation Tips

Start Simple: Begin with basic form fields and add more complex features incrementally.
Use Services: Create dedicated services for PDF manipulation and form handling.
Testing: Thoroughly test PDF interactions across different browsers and devices.
Error Handling: Implement robust error handling for PDF loading and form submission failures.

Sources

Conclusion

Adding interactive components like buttons and input fields on top of PDFs in Angular is achievable through several proven approaches. For your specific needs of implementing signature functionality and date inputs, I recommend:

Start with ngx-extended-pdf-viewer for comprehensive form support and easier implementation of signature tools.
Implement custom overlays for precise control over component positioning and user experience.
Use canvas-based signature pads for a natural signing experience that can be easily integrated with your PDF workflow.
Leverage Angular’s reactive forms for robust form handling and validation.
Consider PDF.js Express for advanced annotation capabilities if your project requires commercial licensing.

The key to success is planning your field detection logic carefully and ensuring proper event handling between your PDF viewer and Angular components. Start with basic implementations and gradually add more sophisticated features as you become familiar with the underlying technologies.

What are the best Angular PDF viewer libraries for interactive forms in 2024?How to implement a digital signature pad in Angular for PDF documents?Can I use PDF.js with Angular to create custom interactive PDF overlays?What are the performance considerations when adding interactive components to PDFs in Angular?How to handle PDF form validation in Angular applications?Are there any open-source alternatives to commercial PDF viewers for Angular interactive forms?

Ask NeuroAgent

How to Add Interactive PDF Components in Angular

Contents

Overview of Approaches

Library-Based Solutions

Custom Overlay Solutions

Hybrid Approaches

Recommended Libraries for Interactive PDFs

ngx-extended-pdf-viewer

Syncfusion PDF Viewer

PDF.js Express

ng2-pdf-viewer

Implementing Signature Functionality

Using Built-in Signature Support

Custom Signature Pad Implementation

Implementing Date Input Fields

Using PDF Form Fields

Custom Date Input Overlay

Custom Overlay Implementation

Code Examples and Implementation

Complete Example with ngx-extended-pdf-viewer

Best Practices and Performance Considerations

Performance Optimization

Accessibility Considerations

Security Considerations

Implementation Tips

Sources

Conclusion