custom_pdf_converter

Description:

custom pdf converter

Pdf creation library for dart/flutter #
This library is divided into two parts:

a low-level Pdf creation library that takes care of the pdf bits generation.
a Widgets system similar to Flutter's, for easy high-level Pdf creation.

It can create a full multi-pages document with graphics,
images, and text using TrueType fonts. With the ease of use you already know.
The source code for a full demo that can run on any Flutter target, and how to build,
it can be found here:
https://github.com/DavBfr/dart_pdf/tree/master/demo/
Use the printing package https://pub.dev/packages/printing
for full flutter print and share operation.
The coordinate system is using the internal Pdf unit:

1.0 is defined as 1 / 72.0 inch
you can use the constants for centimeters, millimeters, and inch defined in PdfPageFormat


Installing #
If you want to print the Pdf document on an actual printer with Flutter,
follow the instructions at https://pub.dev/packages/printing


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


Import the libraries
import 'package:pdf/custom_pdf_converter.dart';
import 'package:pdf/widgets.dart' as pw;
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Examples #
final pdf = pw.Document();

pdf.addPage(pw.Page(
pageFormat: PdfPageFormat.a4,
build: (pw.Context context) {
return pw.Center(
child: pw.Text("Hello World"),
); // Center
})); // Page
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To load an image from a file:
final image = pw.MemoryImage(
File('test.webp').readAsBytesSync(),
);

pdf.addPage(pw.Page(build: (pw.Context context) {
return pw.Center(
child: pw.Image(image),
); // Center
})); // Page
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To load an image from the network using the printing package:
final netImage = await networkImage('https://www.nfet.net/nfet.jpg');

pdf.addPage(pw.Page(build: (pw.Context context) {
return pw.Center(
child: pw.Image(netImage),
); // Center
})); // Page
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To load an SVG:
String svgRaw = '''
<svg viewBox="0 0 50 50" xmlns="http://www.w3.org/2000/svg">
<ellipse style="fill: grey; stroke: black;" cx="25" cy="25" rx="20" ry="20"></ellipse>
</svg>
''';

final svgImage = pw.SvgImage(svg: svgRaw);

pdf.addPage(pw.Page(build: (pw.Context context) {
return pw.Center(
child: svgImage,
); // Center
})); // Page
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To load the SVG from a Flutter asset, use await rootBundle.loadString('assets/file.svg')
To use a TrueType font:
final Uint8List fontData = File('open-sans.ttf').readAsBytesSync();
final ttf = pw.Font.ttf(fontData.buffer.asByteData());

pdf.addPage(pw.Page(
pageFormat: PdfPageFormat.a4,
build: (pw.Context context) {
return pw.Center(
child: pw.Text('Hello World', style: pw.TextStyle(font: ttf, fontSize: 40)),
); // Center
})); // Page
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Or using the printing package's PdfGoogleFonts:
final font = await PdfGoogleFonts.nunitoExtraLight();

pdf.addPage(pw.Page(
pageFormat: PdfPageFormat.a4,
build: (pw.Context context) {
return pw.Center(
child: pw.Text('Hello World', style: pw.TextStyle(font: font, fontSize: 40)),
); // Center
})); // Page
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To display emojis:
final emoji = await PdfGoogleFonts.notoColorEmoji();

pdf.addPage(pw.Page(
pageFormat: PdfPageFormat.a4,
build: (pw.Context context) {
return pw.Center(
child: pw.Text(
'Hello 🐒💁👌🎍😍🦊👨 world!',
style: pw.TextStyle(
fontFallback: [emoji],
fontSize: 25,
),
),
); // Center
})); // Page
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To save the pdf file:
// On Flutter, use the [path_provider](https://pub.dev/packages/path_provider) library:
// final output = await getTemporaryDirectory();
// final file = File("${output.path}/example.pdf");
final file = File("example.pdf");
await file.writeAsBytes(await pdf.save());
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See an interactive demo here: https://davbfr.github.io/dart_pdf/.



Encryption, Digital Signature, and loading a PDF Document #
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.
It implements a PDF parser to load an existing document and add pages, change pages, and add a signature.