It seems to be impossible to find a version of OCR-B, the typeface, that actually is reliably monospaced, meaning that 10 characters, regardless of which characters, always take up the exact same space.

[jwildeboer@social.wildeboer.net]

It seems to be impossible to find a version of OCR-B, the typeface, that actually is reliably monospaced, meaning that 10 characters, regardless of which characters, always take up the exact same space. This makes aligning characters next to impossible First example in Inkscape uses https://github.com/rastislavcore/ocr-b/tree/master/dist, the second example uses https://www.freefontdownload.org/en/ocr-b-regular.font

(details in the ALT text)

[arby@ruhr.social]

@jwildeboer Ich bin nicht sicher, ob die Messung korrekt ist. Monospace bedeutet ja erstmal nur, dass der Abstand vom linken Rand eines Buchstaben zum linken Rand des nächsten Buchstabens ("Dickte") immer gleich ist. Die Zeichen selbst können theoretisch in der Breite abweichen.
Wie man ja auch in deinem Beispiel sehen kann: Das B ist definitiv breiter als das I oder das J. Was man auch sehen kann: Der Abstand ist nicht 2,54, die Zeichen wandern in ihrem "Rahmen" immer weiter nach rechts.

[jwildeboer@social.wildeboer.net]

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[marjolica@social.linux.pizza]

@jwildeboer whenever is see 2.54mm mentioned in a spec. I know it was written by idiots (probably American).

[ptesarik@fosstodon.org]

@jwildeboer But you know how this is usually solved in practice, don't you?
Break up your text into individual glyphs and then align each glyph separately on a 2.54mm boundary…

[thebellman@hachyderm.io]

@jwildeboer I am interested to see how you solve this. My initial thoughts were all wrong and it’s an interesting problem that probably did not exist when the standard was created. The phrasing smells of a time before laser printers.

[jwildeboer@social.wildeboer.net]

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[gruff@stroud.social]

@jwildeboer I sense that the spec was devised in the era of daisy wheels, golfballs and line printers.

[jwildeboer@social.wildeboer.net]

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[jwildeboer@social.wildeboer.net]

OK. I sorta kinda solved it

- Create a textbox, fill it with 30 identical characters (I use spaces)
- Make sure all spacing is set to 0
- Now set the width of that box to the desired size (in the TD1 case 77,7mm) and take note of the character size Inkscape calculates based on that
- Set the three text lines to that character size
- Align the three text lines using the "Align Text Anchors Horizontally" option
- Resize the group again to the desired width of 77,7mm

[jwildeboer@social.wildeboer.net]

For the TD2 sized documents do the same dance but with 2 lines of 36 characters each and a size of 93,3mm. For TD3 (passport) 2 lines with 44 characters and a size of 114mm. It's a pragmatic solution that delivers acceptable results for the MRZ scanners I can test with, so I consider this solved for now.

[0x58@infosec.exchange]

@jwildeboer Working on your passports counterfeiting skills?

[jwildeboer@social.wildeboer.net]

@0x58 I design and create my own documents based on the ICAO9303 standards for my own organisation, which is not a country, so it is no counterfeiting

[0x58@infosec.exchange]

@jwildeboer Practice makes perfect.

[jwildeboer@social.wildeboer.net]

@0x58 10 years of that already under my belt. But now I want to have the complete production process as Open Source.

[hook@toot.si]

@jwildeboer, if you come up with a whole tutorial, I would be quite interested.

@0x58