Tags and labels

The codes you have generated, laid out as things you can print and stick on a product. Every stock size below is a real one in millimetres and the sheet is laid out in millimetres, so what leaves the printer is the size it says — a label sheet 4% out looks fine on screen and ruins a box of Avery. The barcodes are drawn here from the published Code 128 and EAN-13 tables rather than fetched from anywhere, and a code whose check digit is wrong is refused with the digit it should have been.