如何在 C# 中使用 IText7 在现有 pdf 顶部添加条形码？

Question

I'm trying to use IText7 for C# in order to add a Barcode128 at the top of an existing PDF page.

Every examples I've found for the moment are adding the barcode on a new page or are done using iTextSharp or IText5.

If you have any clue of how to perform what I need, I'll be very thankful.

Answer 1

You have several ways to place a barcode on a PDF, as per the examples . I've converted one of the examples into C# for your convenience:

using (var document = new PdfDocument(new PdfReader(SRC), new PdfWriter(DEST)))
        {
            PdfCanvas canvas = new PdfCanvas(document.GetFirstPage());
            Barcode128 code128 = new Barcode128(document);
            code128.SetCode("12345XX789XXX");
            code128.SetCodeType(Barcode128.CODE128);
            PdfFormXObject xObject =
                code128.CreateFormXObject(ColorConstants.BLACK, ColorConstants.BLACK, document);
            float x = 36;
            float y = 750;
            float w = xObject.GetWidth();
            float h = xObject.GetHeight();
            canvas.SaveState();
            canvas.SetFillColor(ColorConstants.LIGHT_GRAY);
            canvas.Rectangle(x, y, w, h);
            canvas.Fill();
            canvas.RestoreState();
            canvas.AddXObject(xObject, 36, 750);
        }

it should be easy to tweak it to do what you are trying to achieve.