EAN Barcodes and GEPIR

A simple search application for searching through the Product Open Database can be found here.

I’ve been working more on Code128 by writing programs that both create Code128 from strings directly and making my own Code128 font based on the Wikipedia entry.

Then I became curious about the EAN13 symbology and thought I’d have a go at making an EAN SVG program that takes the first twelve digits of an EAN and creates a barcode in SVG format.

The Java code can be found on github here.

Here’s some of the more interesting functions.

public class EAN {

	HashMap<String, String[]> table = new HashMap<String, String[]>();
	String lgr;
	String number;
	String binaryString;
	int checksum;

	public static String binToDecSeq(String seq) {
		String s = "";
		int sum = 1;
		for(int i = 1; i < seq.length(); i++) {
			if(seq.charAt(i) != seq.charAt(i - 1)) {
				s = s + sum;
				sum = 1;
			} else {
			if(i == seq.length() - 1) {
				s = s + sum;
		return s;

	public static String createBinaryString(String number, String lgr, HashMap<String, String[]> table) {
		String binaryString = "";
		lgr = lgr + "RRRRRR";
		number = number.substring(1);
		binaryString += "101";
		for(int i = 0; i < number.length(); i++) {
			binaryString += table.get("" + lgr.charAt(i))[Character.getNumericValue(number.charAt(i))];
			if(i == 5)
				binaryString += "01010";
		binaryString += "101";
		return binaryString;
	public static HashMap<String, String[]> makeTable() {
		HashMap<String, String[]> table = new HashMap<String, String[]>();
		table.put("L", new String[] { "0001101", "0011001", "0010011", "0111101", "0100011", "0110001",
				"0101111", "0111011", "0110111", "0001011" });
		table.put("R", new String[] { "1110010", "1100110", "1101100", "1000010", "1011100", "1001110",
				"1010000", "1000100", "1001000", "1110100" });
		table.put("G", new String[] { "0100111", "0110011", "0011011", "0100001", "0011101", "0111001",
				"0000101", "0010001", "0001001", "0010111" });
		return table;
	public static int calculateChecksum(String twelveDigits) {
		int checksum = 0;
		for(int i = 0; i < twelveDigits.length() && i < 12; i++) {
			String s = "" + twelveDigits.charAt(i);
			if(i % 2 == 0) {
				checksum += Integer.parseInt(s) * 1;
			} else {
				checksum += Integer.parseInt(s) * 3;
		checksum = 10 - (checksum % 10);
		return checksum;


Web-Drafter update: Color Picker

My very tiny vector graphics application is improving at a snail pace.

I managed to make a colour picker using jQuery and the HTML range input element.

The code isn’t exactly succinct, but it gets the job done.

Because the program is growing larger, I’m trying to use the OOP facets of JavaScript and put the functions in their respective objects as much as possible, the loose functions in the posfunc.js file creates the dialog:

function color_selector_form(color) {
    frgb = color.get_fill_rgb();
    srgb = color.get_stroke_rgb();

    var red_slider = "<input class='fill_slider' id='red_slider' value="+frgb[0]+" type=\"range\" min=\"0\" max=\"255\"> <br> <div id='rfval' >"+frgb[0]+"</div><br> ";
    var green_slider = "<input class='fill_slider' id='green_slider' value="+frgb[1]+" type=\"range\" min=\"0\" max=\"255\"> <br> <div id='gfval' >"+frgb[1]+"</div><br>";
    var blue_slider = "<input class='fill_slider' id='blue_slider' value="+frgb[2]+" type=\"range\" min=\"0\" max=\"255\"> <br> <div id='bfval' >"+frgb[2]+"</div><br>";
    var fcbox = "<span id=\"fillbox\" style=\"background-color: "+color.fill+"; display: block; height: 50px; width: 50px;\">&nbsp</span>";

    var red_stroke_slider = "<input class='stroke_slider' id='red_stroke_slider' value="+srgb[0]+" type=\"range\" min=\"0\" max=\"255\"> <br> <div id='rsval' >"+srgb[0]+"</div><br> ";
    var green_stroke_slider = "<input class='stroke_slider' id='green_stroke_slider' value="+srgb[1]+" type=\"range\" min=\"0\" max=\"255\"> <br> <div id='gsval' >"+srgb[1]+"</div><br>";
    var blue_stroke_slider = "<input class='stroke_slider' id='blue_stroke_slider' value="+srgb[2]+" type=\"range\" min=\"0\" max=\"255\"> <br> <div id='bsval' >"+srgb[2]+"</div><br>";
    var scbox = "<span id=\"strokebox\" style=\"background-color: "+color.stroke+"; display: block; height: 50px; width: 50px;\">&nbsp</span>";

    var retval = "<table><tr><td>Fill<br><br>";
    retval += "Red: <br>" + red_slider + "Green: <br>" + green_slider + "Blue: <br>" + blue_slider + "<br>" + fcbox;
    retval += "</td><td>&nbsp&nbsp&nbsp</td><td>Stroke<br><br>";
    retval += "Red: <br>" + red_stroke_slider + "Green: <br>" + green_stroke_slider + "Blue: <br>" + blue_stroke_slider + "<br>" + scbox;
    retval += "</td></tr></table>";
    return retval;

While the pos.js has the $(document).ready() functions for the dynamically created elements:

jQuery(document).on("change mousemove", ".fill_slider", function() {
   selected_color.update_fill(jQuery(this).val(), jQuery(this).attr("id"));
   var id = jQuery(this).attr("id");
   //console.log(id + " " +jQuery(this).val());
   if(id.substring(1, 2) == "r") {
       } else  if(id.substring(1, 2) == "g") {
       } else  if(id.substring(1, 2) == "b") {

Which in turn calls the appropriate methods in the MyColor object.

MyColor.prototype.update_fill = function(colorval, id) {
    var hexredval = parseInt(colorval).toString(16);
    if(hexredval.length < 2)
        hexredval = "0" + hexredval;
    var channel = id.substring(0,1);
    if(channel == "r")
        this.fill = (this.fill.substring(0, 1) + hexredval.substring(0, 2) + this.fill.substring(3)).toUpperCase();
    else if(channel == "g")
        this.fill = (this.fill.substring(0, 3) + hexredval.substring(0, 2) + this.fill.substring(5)).toUpperCase();
    else if(channel == "b")
        this.fill = (this.fill.substring(0, 5) + hexredval.substring(0, 2)).toUpperCase();
    jQuery("#" + channel + "fval").html(colorval);
    jQuery("#fillbox").css("background-color", this.fill);

As you can see, the code isn’t really DRY, but I find that making a clumsy solution is a great way to start a project and get anything done whatsoever, and then improve on it (or just keep it until it becomes cluttered).

Interactive jQuery Menu

A few days ago I was asked to update the layout of the website for a store I used to work at.

I thought this was a good chance to get to know jQuery animations, so I put together a bunch of stock images as background, edited pictures of frames and put some text in the frames for the icons.

I worked with artboards in Affinity Designer so I could export multiple images to different files, I also worked with groups and a transparent background so I could make .png files of the frames and put them on top of the background images.

That way I used the background-image css property, with display set to block and could superimpose a png with transparency over another image.

With jQuery I selected all images, where each image has a class “RT” and I used the reserved word this to select the particular instance for mouseover and mouseleave events.

With this I managed to make a fun little menu where the frame with the text grows and shrinks according to mouse-events.

The result can be seen here.


I noticed that my programming page was sadly empty.

So to have some actual content I started writing a bit about C so I can rehash and remind myself of what I’ve learned about the C programming language.

It’s some really basic stuff, and of course, I’ve made programs to do a lot more than just print to terminal and work on simple variables, but I have to start somewhere when I write about that stuff.

Let's start at the very beginning. 

A very good place to start.

When you read you begin with ABC.

When you code you compile with G C C

Fontstats Plugin

Today I finished a little WordPress plugin I’ve been working on.

It’s a two part plugin, one php script collects data from any Norwegian designer on DaFont by visiting each site, and by the power of Regex-Grayskull it inserts it into a database on my website.

The WordPress plugin then selects the last sampled date and displays it in a HTML-table on any post or page where I insert the registered shortcode.

Here’s the result:

No.DownloadsDesignerDate SampledCountry
1104003208Måns Grebäck2018-06-25Sweden
222327863Pizzadude - Jakob Fischer2018-06-25Denmark
34461415Johan Waldenström2018-06-25Sweden
43375502Mr.fisk Fonts - Mike Larsson2018-06-25Sweden
53208340Fontourist - Hans Gerhard Meier2018-06-25Norway
63182490Carl Krull2018-06-25Denmark
72686973Listemageren - Klaus Johansen2018-06-25Denmark
82501568Johan Aakerlund2018-06-25Denmark
92365834CheapProFonts - Roger S. Nelsson2018-06-25Norway
111246530Flight of the Dragon - Hasan Guven2018-06-25Norway
121034712Christian Munk2018-06-25Denmark
13710440Your Own Font - Ellinor Rapp2018-06-25Sweden
14547581Vinterstille TypeFaceLab - Klaus Nielsen2018-06-25Denmark
15523780Adam Ericsson2018-06-25Sweden
17473049Viktor Hammarberg2018-06-25Sweden
18428107Moonbase Press - Svein Kåre Gunnarson2018-06-25Norway
19404563Espen Morten Kvalheim2018-06-25Norway
20348166Staffan Vilcans2018-06-25Sweden
21317035Martin Holm2018-06-25Norway
22312512Jonas Borneland Hansen2018-06-25Denmark
23303609Thor Christopher Arisland2018-06-25Norway
24232332Norwegian Ink / Design for Dough - Frode Nordbø2018-06-25Norway
25204084Anton - Anton Lundström2018-06-25Sweden
26203428David Engelby2018-06-25Denmark
27197013dawnland - Daniel Viberg2018-06-25Sweden
28173318211178 Creative Agency - Morten Talleivsen2018-06-25Norway
29131332Martin Sørensen2018-06-25Denmark
3189301Joaquim Marquès Nielsen2018-06-25Denmark
3288879Andreas Larsen2018-06-25Denmark
3387603Nils Kähler2018-06-25Denmark
3482378Pär Lundkvist2018-06-25Sweden
3580185Anton Bohlin2018-06-25Sweden
3675397Digital Flame Studios - sindre små2018-06-25Norway
3862241huskmelk - Rashid Akrim2018-06-25Norway
3960303Kyrre Honohan2018-06-25Norway
4054651Pia Hed Aspell2018-06-25Sweden
4152751Nadia Rosenfeldt2018-06-25Denmark
4251093Linn Mustanoja2018-06-25Sweden
4348483Lars Håhus2018-06-25Sweden
4443404ronjam - Ronja Melcker2018-06-25Sweden
4540533Atle Mo2018-06-25Norway
4635735Erik Jeddere-Fisher2018-06-25Norway
4831826benjamin rauber2018-06-25Sweden
4930271Arman Ay2018-06-25Sweden
5026811Mark Lund2018-06-25Norway
5225739Andrew Nordquist2018-06-25Sweden
5325630Botond Bokor2018-06-25Sweden
5425557Dan Thorup2018-06-25Denmark
5524353Aske Ching2018-06-25Denmark
5720539Bull - Sandra Madsen2018-06-25Denmark
5820126David Lindecrantz2018-06-25Sweden
5920108Henrik Johansson2018-06-25Sweden
6019749Erik Holm2018-06-25Norway
6119738Kristian Dalen2018-06-25Norway
6219587Carl Enlund2018-06-25Sweden
6316904Mandy Pandy2018-06-25Sweden
6414428Christian Koch2018-06-25Denmark
6512831Alexander Rossebø2018-06-25Norway
6612485Johan Brodd2018-06-25Sweden
6711055Viktor Örneland2018-06-25Sweden
689427Mathias Alvebring2018-06-25Sweden
708124Studio Indigo - Helena Öhman2018-06-25Sweden
727491Mathias Rue2018-06-25Denmark
736810Manuela Hardy2018-06-25Norway
756451Sara Lindberg2018-06-25Sweden
766375Gröt Havregrynsson2018-06-25Sweden
776249Mattis Folkestad2018-06-25Norway
785369Oliver Waldemar2018-06-25Sweden
794863Simon Jakobsson2018-06-25Sweden
804168KingDGaming - Elias Eriksson2018-06-25Sweden

Regex 101

Today I received an email from the store I used to work at asking me to make a printer friendly version of an online table of information.

As I learned more about regular expressions from the “INF3331” course I took this fall, solving this problem proved to be way easier than any previous attempts at the likes of it.

At times I’ve thought that regexes are harder to read and debug than ordinary programming languages, but with a good editor like Atom or the regex101 page, it all became a lot less stressful.

As far as editors go, I have to admit that I still use emacs when I’m not using an IDE or GUI-editor.

Note to self about regular expressions.

(.*?) to capture zero or more characters in a non-greedy manner

(?:.*?) for the same grouping without backreferences.

$1 or $[group-number] for backreferences in JavaScript and Atom

\1 or \[group-number] for backreferences in Python, PHP.

Perl and PHP also uses \g1 or \g[group-number] for backreferences.

The following characters need to be escaped in regex:


Web Drafter

A tiny online vector graphics application.

Click here to try it out.

As a small project to familiarise myself with JavaScript, jQuery and SVG I started working on a small vector graphics app using the SVG.js library.

At first I was thinking of manipulating SVG-text directly as I had done with my desktop Java applications, but since I found that simply appending or updating the inner html of divs didn’t refresh the SVG canvas and other annoying things I found it was smarter to just use a simple JavaScript library for this.

In addition to learning a lot of jQuery and JavaScript, especially understanding the specifics of JavaScripts idiosyncratic approach to OOP, I learned a bit about which existing libraries there are and how to use them. For this small application, SVG.js did nicely, but I also learned about a larger library called Raphaël, and an interesting little script called Flowtype, that automagically resizes the font size in relation to the window size.

I put the source code of my little application on GitHub here.

Up to now I’ve only managed to do the most basic rectilinear polygons, with the foundations set for snapping and I’m planning to create a simple colour-picker functionality for the stroke, fill and opacity.

The hotkeys are:

cmd+z – UNDO (mac)

ctrl+z – UNDO (windows, linux)

D – Delete the last polygon.

S – Show data on the selected polygon.

Polygons are created by closing the path.

This is done by creating a line where the end coordinate is the same as the first coordinate of the polygon.