pdf_annotations

A Flutter plugin for adding text and freehand annotations to PDF documents.

This package provides a PdfAnnotationsView widget that displays a PDF and allows users to draw lines (pen/highlighter) and add text annotations on top of it. It supports zooming, panning, undo/redo, and saving the annotations back to a new PDF file.

Features

• View PDFs: Render PDF documents with zoom and pan capabilities.
• Freehand Drawing: Draw on the PDF using a pen or highlighter tool.
• Text Annotations: Add text to the PDF. Drag and drop the current text annotation to move it around the PDF
• Customization: enhancing color, stroke width, font size, and font family.
• Undo/Redo: robust state management for annotation actions.
• Save & Export: Merge annotations into the PDF and save as a new file.

Getting Started

Add pdf_annotations to your pubspec.yaml:

dependencies:
  pdf_annotations: ^1.0.0-beta.2

Usage

Import the package:

import 'package:pdf_annotations/pdf_annotations.dart';

Use the PdfAnnotationsView widget in your widget tree. You need to provide a PdfAnnotationsViewController to control the view's actions.

import 'package:flutter/material.dart';
import 'package:pdf_annotations/pdf_annotations.dart';

class MyPdfViewer extends StatefulWidget {
  final String pdfPath;

  const MyPdfViewer({super.key, required this.pdfPath});

  @override
  State<MyPdfViewer> createState() => _MyPdfViewerState();
}

class _MyPdfViewerState extends State<MyPdfViewer> {
  final PdfAnnotationsViewController _controller = PdfAnnotationsViewController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Annotate PDF'),
        actions: [
          IconButton(
            icon: const Icon(Icons.undo),
            onPressed: () => _controller.undo(),
          ),
          IconButton(
            icon: const Icon(Icons.redo),
            onPressed: () => _controller.redo(),
          ),
          IconButton(
            icon: const Icon(Icons.save),
            onPressed: () async {
              await _controller.saveAnnotations();
              // The original file is not overwritten by default, check specific implementation details.
            },
          ),
        ],
      ),
      body: PdfAnnotationsView(
        pdfPath: widget.pdfPath,
        pdfDefaultScale: 1.0,
        startPage: 0,
        initialOffset: Offset.zero,
        initialAnnotationColour: Colors.red,
        initialFontSize: 14.0,
        initialFontFamily: 'Arial',
        pdfZoom: 1.0,
        pdfAnnotationsViewController: _controller,
        onZoomUpdate: (zoom) {
          // Handle zoom update
        },
        onDefaultScaleUpdate: (scale) {
          // Handle scale update
        },
        onPageChanged: (page) {
          print('Page changed to: $page');
        },
        onError: (error) {
          print('Error: $error');
        },
      ),
      bottomNavigationBar: BottomAppBar(
        child: Row(
          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
          children: [
            IconButton(
              icon: const Icon(Icons.edit),
              onPressed: () => _controller.setEditMode(EditMode.draw),
            ),
            IconButton(
              icon: const Icon(Icons.text_fields),
              onPressed: () => _controller.setEditMode(EditMode.text),
            ),
            IconButton(
              icon: const Icon(Icons.pan_tool),
              onPressed: () => _controller.setEditMode(EditMode.pan),
            ),
          ],
        ),
      ),
    );
  }
}

Controller Methods

The PdfAnnotationsViewController exposes several methods to interact with the view programmatically:

• undo(): Undo the last annotation action.
• redo(): Redo the last undone action.
• saveAnnotations(): Save the current annotations to the file system.
• setAnnotationColour(Color color): Change the current drawing/text color.
• setLineMode(LineMode mode): Switch between pen and highlighter.
• setEditMode(EditMode mode): Switch between text, draw, and pan modes.
• setFontSize(double size): Set the font size for text annotations.
• setFontFamily(String family): Set the font family for text annotations.

Contribution

Contributions are welcome! If you find a bug or want to add a feature, please feel free to open an issue or submit a pull request.

License

This project is licensed under the MIT License - see the LICENSE file for details.