How to convert image to PDF in Syncfusion Flutter PDF Library?

The Flutter PDF library is used to create, read, and edit PDF documents programmatically without Adobe dependencies. Using this library, you can convert image to PDF document using Flutter.  

Steps to convert image to PDF document programmatically:

1. Create a new Flutter application project.

2. Open Visual Studio Code (After installing the Dart and Flutter extensions as stated in this setup editor page).

3. Click View -> Command Palette.

3. Type Flutter and choose Flutter: New Project.

4. Enter the project name and press the Enter button.
5. Now choose the location of the project.

2. Add the following code in your pubspec.yaml file to install the syncfusion® flutter pdf package in your application. It will be automatically downloaded from the pub  once you trigger the flutter pub get a comment or Get packages option from the Visual studio code.

   dependencies:
     syncfusion_flutter_pdf: ^20.3.49
   

1. Import the following package in your main.dart file.

   import 'package:syncfusion_flutter_pdf/pdf.dart';
   

3. Add the following code in lib/main.dart file to create a simple button.

   @override
     Widget build(BuildContext context) {
       return Scaffold(
         appBar: AppBar(
           title: Text(widget.title),
         ),
         body: Center(
           child: Column(
             mainAxisAlignment: MainAxisAlignment.center,
             children: <Widget>[
               TextButton(
               child: Text(
                 'Convert image to PDF document',
                 style: TextStyle(color: Colors.white),
               ),
               style: ButtonStyle(
                   backgroundColor: MaterialStateProperty.resolveWith(
                       (states) => Colors.blue)),
               onPressed: _convertImageToPDF,
             )
             ],
           ),
         ),
       );
     }
    
   

4. Include the following code snippet in the _convertImageToPDF method to convert an image to PDF document.

   Future<void> _convertImageToPDF() async {
    
     //Create the PDF document
     PdfDocument document = PdfDocument();
    
     //Add the page
     PdfPage page = document.pages.add();
    
     //Load the image
     final PdfImage image =
         PdfBitmap(await _readImageData('Autumn Leaves.jpg'));
    
     //draw image to the first page
     page.graphics.drawImage(
         image, Rect.fromLTWH(0, 0, page.size.width, page.size.height));
    
       //Save the document
       List<int> bytes = await document.save();
    
       // Dispose the document
       document.dispose();
    
       //Save the file and launch/download
       SaveFile.saveAndLaunchFile(bytes, 'output.pdf');
     }
    
   

5. Use the following code to load an image in the Flutter project.

1. Add the following code in your pubspec.yaml file.

   flutter:
     # To add assets to your application, add an assets section, like this:
     assets:
       - images/
   

2. Import the following package in your main.dart file.

   import 'package:flutter/services.dart';
   

3. Add the following code in the lib/main.dart file to read the existing image file.

   Future<List<int>> _readImageData(String name) async {
   final ByteData data = await rootBundle.load('images/$name');
     return data.buffer.asUint8List(data.offsetInBytes, data.lengthInBytes);
   

6. Follow the below steps to launch the generated PDF file on desktop, mobile, and web platforms.

Web:

1. Add the web package as a dependency in your pubspec.yaml file. Then, create a new Dart file named save_file_web.dart. Finally, add the following code to implement the file download functionality using the web package.  

   import 'dart:convert';
   import 'package:web/web.dart' as web;

2. To enable file saving and initiate downloads in a Flutter web environment, use the following code within the saveAndLaunchFile method.

   // Function to save and launch a file for download in a web environment
   Future<void> saveAndLaunchFile(List<int> bytes, String fileName) async {
     final web.HTMLAnchorElement anchor =
         web.document.createElement('a') as web.HTMLAnchorElement
           ..href = "data:application/octet-stream;base64,${base64Encode(bytes)}"
           ..style.display = 'none'
           ..download = fileName;
   
   // Insert the new element into the DOM
   web.document.body!.appendChild(anchor);
   
   // Initiate the download
   anchor.click();
   // Clean up the DOM by removing the anchor element
   web.document.body!.removeChild(anchor);
   }

Desktop and mobile:

3. Add the following dependencies in your pubspec.yaml file.

   open_file: ^3.2.1
   path_provider: ^2.0.11 #Open source library to launch the PDF file in mobile devices
   

4. Create a new dart file named save_file_mobile_and_desktop.dart under the lib folder and import the following packages in save_file_mobile_and_desktop.dart file.

   import 'dart:io';
   import 'package:open_file/open_file.dart';
   import 'package:path_provider/path_provider.dart';
   

5. Include the following code snippet in save_file_mobile_and_desktop.dart to open the PDF document in Desktop and Mobile.

   class SaveFile {
     static Future<void> saveAndLaunchFile(
         List<int> bytes, String fileName) async {
       //Get external storage directory
       Directory directory = await getApplicationSupportDirectory();
       //Get directory path
       String path = directory.path;
       //Create an empty file to write PDF data
       File file = File('$path/$fileName');
       //Write PDF data
       await file.writeAsBytes(bytes, flush: true);
       //Open the PDF document in mobile
       OpenFile.open('$path/$fileName');
     }
   }
    
   

7. Run the sample using the flutter run command. This will convert the image into a PDF document. After the application launches, you will get the PDF document as follows.

A complete working sample can be downloaded from ImageToPDFSample.zip

Take a moment to peruse the documentation for working with images, where you will find other options like inserting, applying transparency and rotation.

I hope you enjoyed learning about how to convert image to PDF in Syncfusion® Flutter PDF Library.

You can refer to our  Flutter PDF feature tour page to know about its other groundbreaking feature representations. You can also explore our Flutter PDF documentation to understand how to create and manipulate data.

For current customers, you can check out our components from the License and Downloads page. If you are new to Syncfusion®, you can try our 30-day free trial to check out our other controls.

If you have any queries or require clarifications, please let us know in the comments section below. You can also contact us through our support forums, Direct-Trac, or feedback portal. We are always happy to assist you!