Drawing circle on existing PDF using itextsharp c#

Question

I got some troubles drawing circle on an existing pdf, I found a code to add text on existing PDF, I tried to adapt it to draw circle but the result is just a blank page Does anyone have an idea how to fix this?

My code:

        string oldFile = @"C:\...6166-21.pdf";
        string newFile = @"C:\...NEW.pdf";

        // open the reader
        PdfReader reader = new PdfReader(oldFile);
        Rectangle size = reader.GetPageSizeWithRotation(1);
        Document document = new Document(size);

        FileStream fs = new FileStream(newFile, FileMode.Create, FileAccess.Write);
        PdfWriter writer = PdfWriter.GetInstance(document, fs);
        document.Open();

        // the pdf content
        PdfContentByte cb = writer.DirectContent;

        cb.Circle(150f, 150f, 50f);
        cb.SetColorStroke(iTextSharp.text.BaseColor.GREEN);

        // create the new page and add it to the pdf
        PdfImportedPage page = writer.GetImportedPage(reader, 1);
        cb.AddTemplate(page, 0, 0);

        // close the streams and voilá the file should be changed :)
        document.Close();
        fs.Close();
        writer.Close();
        reader.Close();

Answer 1

You forgot to add cb.Stroke();

Please try like this:

cb.SetColorStroke(iTextSharp.text.BaseColor.GREEN);
cb.Circle(150f, 150f, 50f);
cb.Stroke();