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PDF Library

Create, load and edit PDF files in Dart with dox_pdf_lib, and send them from a Dox controller.

dox_pdf_lib draws text, shapes, SVG paths, JPEG and PNG images. It also does forms, attachments, metadata, custom fonts, and PDF/A and PDF/X. It has the API of the pdf-lib JavaScript library.

The package is standalone. It does not need Dox, and Dox does not need it. To fill pdfme templates, see pdfme.

Install

dart pub add dox_pdf_lib

Send a PDF from a controller

A controller can return a DownloadableFile. Dox streams the bytes and sets Content-Type and Content-Disposition. The browser saves the file. See Response.

Use StreamFile instead to show the PDF in the browser tab.

lib/app/http/controllers/report.controller.dart
import 'dart:io';
import 'dart:typed_data';

import 'package:dox_core/dox_core.dart';
import 'package:dox_pdf_lib/dox_pdf_lib.dart';

@Inject()
class ReportController {
  Future<DownloadableFile> show(DoxRequest req) async {
    PDFDocument doc = await PDFDocument.create();
    PDFFont font = await doc.embedFont(StandardFonts.helvetica);
    PDFPage page = doc.addPage(PageSizes.A4);
    page.drawText('Monthly report', x: 50, y: 750, font: font, size: 24);

    Uint8List bytes = await doc.save();
    return DownloadableFile(
      ContentType('application', 'pdf'),
      Stream<List<int>>.value(bytes),
      'report.pdf',
      length: bytes.length,
    );
  }
}
lib/routes/api.dart
Route.get('/report.pdf', (ReportController c) => c.show);

Fonts

The 14 standard PDF fonts, like Helvetica, are built in. They only have Latin letters. For other languages, embed your own TrueType or OpenType font. Use subset: true to put only the letters you use into the file.

Uint8List bytes = File('NotoSansThai-Regular.ttf').readAsBytesSync();
PDFFont thai = await doc.embedFont(bytes, subset: true);
page.drawText('สวัสดีครับ', x: 50, y: 700, font: thai, size: 20);

Thai, Myanmar, Khmer, Lao, Arabic, Hebrew and Hindi text is laid out correctly. Line breaks in Myanmar, Thai, Khmer and Lao go between words.

PDF/A and PDF/X

PDF/A is for long-term archives. PDF/X is for print. One call, setConformance, sets up a document for the standard you pick.

You bring the ICC profile. The package ships none.

Uint8List srgb = File('sRGB2014.icc').readAsBytesSync();

PDFDocument doc = await PDFDocument.create();
doc.setTitle('Annual report');
doc.setConformance(
  PDFStandard.pdfA2b,
  iccProfile: srgb,
  outputConditionIdentifier: 'sRGB IEC61966-2.1',
);

// PDF/A needs fonts from a font file. Standard fonts do not work.
PDFFont font = await doc.embedFont(
  File('NotoSans-Regular.ttf').readAsBytesSync(),
  subset: true,
);
doc.addPage().drawText('Kept for a long time', x: 50, y: 750, font: font);

for (ConformanceIssue issue in doc.checkConformance(PDFStandard.pdfA2b)) {
  print(issue);
}

checkConformance lists what is still wrong. For PDF/X, use PDFStandard.pdfX1a, pdfX3 or pdfX4, and give each page a trim box. The dox_pdf_lib README has the full list of rules.

Platforms

dox_pdf_lib uses dart:ffi and a small native library. It runs in Dart programs on macOS, Linux and Windows.

They do not run on the web, iOS or Android.

A ready-built native library is downloaded for you, so you do not need Rust.

On Linux, the ready-built library needs glibc 2.35 or newer, for example Ubuntu 22.04 or Debian 12. On older Linux, or on Alpine, build the library yourself. The dox_pdf_lib README shows how.

Without Dox

The same code works in any Dart program. Call PDFDocument.create(), then write the bytes to a file:

import 'dart:io';

import 'package:dox_pdf_lib/dox_pdf_lib.dart';

Future<void> main() async {
  PDFDocument doc = await PDFDocument.create();
  PDFFont font = await doc.embedFont(StandardFonts.helvetica);
  PDFPage page = doc.addPage(PageSizes.A4);
  page.drawText('Hello, PDF!', x: 50, y: 750, font: font, size: 30);
  File('hello.pdf').writeAsBytesSync(await doc.save());
}

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