Printing

A plugin that allows Flutter apps to generate and print documents to android or ios compatible printers

See the example on how to use the plugin.

Example document

This example is also available on the web here: davbfr.github.io/dart_pdf/.

This plugin uses the pdf package pub.dev/packages/pdf for pdf creation. Please refer to pub.dev/documentation/pdf/latest/ for documentation.

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Installing

  1. Add this package to your package's pubspec.yaml file as described on the installation tab

  2. Import the libraries

    import 'package:pdf/pdf.dart';
    import 'package:pdf/widgets.dart' as pw;
    import 'package:printing/printing.dart';
    
  3. Enable Swift on the iOS project, in ios/Podfile:

    target 'Runner' do
       use_frameworks!    # <-- Add this line
    
  4. For MacOS add printing capability by opening macos directory in XCode

Examples

final doc = pw.Document();

doc.addPage(pw.Page(
      pageFormat: PdfPageFormat.a4,
      build: (pw.Context context) {
        return pw.Center(
          child: pw.Text("Hello World"),
        ); // Center
      })); // Page

To load an image from an ImageProvider:

const imageProvider = const AssetImage('assets/image.png');
final PdfImage image = await pdfImageFromImageProvider(pdf: doc.document, image: imageProvider);

doc.addPage(pw.Page(
    build: (pw.Context context) {
      return pw.Center(
        child: pw.Image(image),
      ); // Center
    })); // Page

To use a TrueType font from a flutter bundle:

final font = await rootBundle.load("assets/open-sans.ttf");
final ttf = pw.Font.ttf(font);

doc.addPage(pw.Page(
    build: (pw.Context context) {
      return pw.Center(
        child: pw.Text('Dart is awesome', style: pw.TextStyle(font: ttf, fontSize: 40)),
      ); // Center
    })); // Page

To save the pdf file using the path_provider library:

final output = await getTemporaryDirectory();
final file = File("${output.path}/example.pdf");
await file.writeAsBytes(doc.save());

You can also print the document using the iOS or Android print service:

await Printing.layoutPdf(
      onLayout: (PdfPageFormat format) async => doc.save());

Or share the document to other applications:

await Printing.sharePdf(bytes: doc.save(), filename: 'my-document.pdf');

To print an HTML document:

await Printing.layoutPdf(
    onLayout: (PdfPageFormat format) async => await Printing.convertHtml(
          format: format,
          html: '<html><body><p>Hello!</p></body></html>',
        ));

Convert a Pdf to images, one image per page, get only pages 1 and 2 at 72 dpi:

await for (var page in Printing.raster(doc.save(), pages: [0, 1], dpi: 72)) {
  final image = page.toImage(); // ...or page.toPng()
  print(image);
}

To print an existing Pdf file from a Flutter asset:

final pdf = await rootBundle.load('document.pdf');
await Printing.layoutPdf(onLayout: (_) => pdf.buffer.asUint8List());

Display your PDF document

This package also comes with a PdfPreview widget to display a pdf document.

PdfPreview(
  build: (format) => doc.save(),
);

This widget is compatible with Android, iOS, macOS and web.

For the web, a javascript library and a small script has to be added to your web/index.html file:

<script src="//cdnjs.cloudflare.com/ajax/libs/pdf.js/2.4.456/pdf.min.js"></script>
<script type="text/javascript">
     pdfjsLib.GlobalWorkerOptions.workerSrc = "//cdnjs.cloudflare.com/ajax/libs/pdf.js/2.4.456/pdf.worker.min.js";
</script>

Designing your PDF document

A good starting point is to use PdfPreview which features hot-reload pdf build and refresh.

Take a look at the example tab for a sample project.

Update the _generatePdf method with your design.

Future<Uint8List> _generatePdf(PdfPageFormat format, String title) async {
    final pdf = pw.Document();

    pdf.addPage(
      pw.Page(
        pageFormat: format,
        build: (context) => pw.Placeholder(),
      ),
    );

    return pdf.save();
  }

This widget also features a debug switch at the bottom right to display the drawing constraints used. This switch is available only on debug builds.

Moving on to your production application, you can keep the _generatePdf function and print the document using:

final title = 'Flutter Demo';
await Printing.layoutPdf(onLayout: (format) => _generatePdf(format, title));

Encryption and Digital Signature

Encryption using RC4-40, RC4-128, AES-128, and AES-256 is fully supported using a separate library. This library also provides SHA1 or SHA-256 Digital Signature using your x509 certificate. The graphic signature is represented by a clickable widget that shows Digital Signature information.

Drop me an email for availability and more information.

Libraries

printing