How can I add a barcode to a pdf + pages (envelop) numbering?

Q: How can I add a barcode to a pdf + pages (envelop) numbering?
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A: You could use ElementBuilder & ElementWriter as shown in
ElementBuilder sample project (http://www.pdftron.com/pdfnet/
samplecode.html#ElementBuilder). The barcode can be either a text run
element (used in conjunction with appropriate barcode font) or an
image (see AddImage sample for an example of how to add an image to
PDF). Alternatively you can also use the new Stamper utility class (as
shown in Stamper sample) which is a bit easier to use but less
flexible than ElementBuilder/ElementWriter.