Fighting with computers

Computers are not always friendly.

Friday, February 13, 2015

Barcode listings with data

A few weeks ago I mentioned a new tool I created for (allegedly) making my life easier when delivering marked exams to my students. Then I covered the process that happens after the exam. But one key element it was not mentioned is what it needs to do in advance.

For my system I needed a set of labels. My prototype used Code-128 barcode that can handle ASCII code to encode each student email using barcode command-line program for Linux. The only problem with that was the lack of additional information being added to the label, such as the student name.

Looking around I found a very handy tool by AVERY company, that helps you creating labels on-line for all their range of labels. What is even better is the tool will allow you to upload an excel file with data columns, like names and addresses to create a custom listing you designed and export it as PDF (they offer to print it for you to and deliver the labels to your office too).

After some tweaks and, the most difficult part, discovering the reference of my European A4 labels on their site, I get a set of working labels but this time using 2D QR codes that are a bit more reliable than 1D barcodes.

But I was left with a bit of an itch that I should be looking for a way of solving the problem entirely with my own software instead of using an online application, as importing a new list of students required a bit of touching here and there.

Not knowing what could do the job more easily, I turned to the ZXing library I am already using for decoding and I saw there is an encoder too. And given that creating a PDF output seemed to work well for AVERY I decided to do the same, this time using Processing, as it tends to make my life easier than when using Java.


The function above will create a QR code as an image you can later place inside a PDF page following the pattern you want. Going from BufferedImage to PImage took me like one hour to get right, as it seems Processing has been going through different solutions to that in the past, most of them no longer working.

So now I do have a tool that creates the labels from a CSV files with students name and addresses. I am looking forward to use these tools in the coming months.

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