Write Arabic text in a PDF in C#

Write a right to left paragraph with an embedded Arabic font, numbers and currency included.

Short answer

Load a font that covers Arabic with PdfOpenTypeFont.Load, put the text in a PdfParagraph with Direction = PdfTextDirection.RightToLeft, and draw it with DrawText. Letters join and take their contextual forms, and the text carries ActualText, so it copies and searches in logical order.

recipe-arabic-text-pdf.cs

#:package PdfNetStack@1.2.0
using PdfNetStack;
using PdfNetStack.Drawing;
using PdfNetStack.Fonts;

PdfFont arabic = PdfOpenTypeFont.Load("fonts/NotoSansArabic-Regular.woff2");   // embedded as a subset
PdfFont latin = PdfOpenTypeFont.Load("fonts/Inter-Regular.woff2");
var style = new PdfTextStyle(arabic, 20) { Fallbacks = [latin] };               // digits and the euro sign

PdfDocument doc = PdfDocument.Create();
PdfPage page = doc.Pages.Add(PdfRectangle.A4);
using (PdfGraphics g = page.CreateGraphics())
{
    var paragraph = new PdfParagraph { Direction = PdfTextDirection.RightToLeft, LineHeight = 1.6 }
        .Add("المبلغ المستحق: 1,250.00 € خلال ثلاثين يوما من تاريخ الفاتورة.", style);
    g.DrawText(paragraph, 60, 60, page.Width - 120);   // top left corner and width
}
doc.Save("arabic.pdf");

Console.WriteLine(PdfDocument.Open("arabic.pdf").Pages[0].ExtractText());   // logical order

Notes

• The font is embedded as a subset of the glyphs drawn. TrueType, OpenType, WOFF and WOFF2 files load the same way.
• A font that lacks some characters, such as Latin letters, digits or the euro sign, borrows them from the fonts in Fallbacks on the PdfTextStyle, as the sample does with Inter.
• Numbers keep their left to right order inside the right to left line, as the Unicode bidirectional algorithm places them.
• doc.Viewer.RightToLeft = true tells viewers the document reads right to left, which sets the order of pages shown side by side.

Related

• Fonts and text
• Extract text
• API: PdfParagraph, PdfTextStyle, PdfOpenTypeFont