use fonts in pdf library custom code

i can't use custom or the theme fonts in my custom action code that generates pdf based on arguments here is my code : // Automatic FlutterFlow imports import 'package:pdf/pdf.dart'; import 'package:pdf/widgets.dart' as pw; import 'package:printing/printing.dart'; Future pdfTest( String schoolName, String officeName, String department, String creatorName, String schoolManagerName, String programName, String dateOfCreation, String numberOfPeople, ) async { // Load the custom font final pdf = pw.Document(); // final fontData = await rootBundle.load('assets/Rubik-Regular.ttf'); // final customFont = pw.Font.ttf(fontData.buffer.asByteData()); // Title of the page pdf.addPage(pw.Page( pageFormat: PdfPageFormat.a4, build: (pw.Context context) { return pw.Column(children: [ pw.Text("تقرير", // Arabic text for "Report" style: pw.TextStyle( font: theme.defaultFont, fontSize: 40, ), textAlign: pw.TextAlign.right),