pdf_acroform

A Dart/Flutter package for parsing PDF AcroForm fields and displaying interactive form overlays.

Features

• Parse AcroForm fields from PDF documents
• Extract field metadata: name, type, position, default values
• Support for text fields, checkboxes, dropdowns, and more
• Field properties: multiline, read-only, max length, text alignment
• Flutter widget to display PDF with editable form overlays
• Pure Dart parser (works without Flutter)

Installation

Add to your pubspec.yaml:

dependencies:
  pdf_acroform:
    git:
      url: https://github.com/alpaga-dev/pdf_acroform.git

Usage

Parsing PDF form fields (Dart)

import 'package:pdf_acroform/pdf_acroform.dart';

// Parse a PDF file
final parser = await AcroFormParser.fromFile('form.pdf');
final fields = await parser.extractFields();

// List all fields
for (final field in fields) {
  print('${field.name}: ${field.type}');
}

// Extract pre-filled values as a Map
final formData = fields.extractFormData();
print(formData); // {'firstName': 'John', 'newsletter': true, ...}

// Filter fields
final textFields = fields.ofType(PdfFieldType.text);
final page1Fields = fields.forPage(0);

Displaying PDF with form overlays (Flutter)

import 'package:pdf_acroform/pdf_acroform.dart';
import 'package:pdf_acroform/pdf_acroform_viewer.dart';

class MyFormScreen extends StatefulWidget {
  @override
  State<MyFormScreen> createState() => _MyFormScreenState();
}

class _MyFormScreenState extends State<MyFormScreen> {
  List<PdfFormField>? _fields;
  Map<String, dynamic> _formData = {};

  @override
  void initState() {
    super.initState();
    _loadPdf();
  }

  Future<void> _loadPdf() async {
    final parser = await AcroFormParser.fromFile('form.pdf');
    final fields = await parser.extractFields();
    setState(() {
      _fields = fields;
      _formData = fields.extractFormData();
    });
  }

  @override
  Widget build(BuildContext context) {
    if (_fields == null) {
      return const Center(child: CircularProgressIndicator());
    }

    return PdfFormViewer(
      pdfPath: 'form.pdf',
      fields: _fields!,
      formData: _formData,
      readOnlyFields: {'signatureDate', 'referenceNumber'}, // Optional
      onFieldChanged: (name, value) {
        setState(() => _formData[name] = value);
      },
    );
  }
}

Supported field types

Type	Description
text	Single or multiline text input
button	Checkbox or radio button
choice	Dropdown or list selection
signature	Signature field (detected but not editable)

PdfFormViewer options

Parameter	Type	Description
pdfPath	String	Path to the PDF file
fields	List<PdfFormField>	Fields extracted from the PDF
formData	Map<String, dynamic>	Current form values
onFieldChanged	Function(String, dynamic)	Callback when a field value changes
readOnlyFields	Set<String>	Field names to display as read-only (optional)

The readOnlyFields parameter allows you to make specific fields non-editable at runtime, regardless of their read-only status in the PDF. This is useful for:

• Locking pre-filled fields that shouldn't be modified
• Implementing role-based field permissions
• Creating partial preview modes

Field properties

The parser extracts the following properties when available:

• name - Fully qualified field name
• type - Field type (text, button, choice, signature)
• rect - Position and dimensions on the page
• pageIndex - Zero-based page number
• defaultValue - Pre-filled value
• isMultiline - Whether text field supports multiple lines
• isReadOnly - Whether field is editable
• maxLength - Maximum character count
• alignment - Text alignment (left, center, right)
• options - Available choices for dropdown fields

Example app

See the example/ directory for a complete demo application.

cd example
flutter run

License

MIT