Why are QR Codes with capital letters smaller than QR codes with lower-case letters?
shkspr.mobi
Take a look at these two QR codes. Scan them if you like, I promise there's nothing dodgy in them.     Left is upper-case HTTPS://EDENT.TEL/ and right is lower-case https://edent.tel/ You can clearly see that the one on the left is a "smaller" QR as it has fewer bits of data in it. Both go to the same URl, the only difference is the casing. What's going on? Your first thought might be th…

All uppercase text is unreadable and ugly as fuck. But it is what it is… if you typeset QR codes and can work within a small character set, you’re trapped with all uppers.

So then the question is, what can be safely converted to all uppercase without breaking? Apparently schemes, domain names and email addresses.

But what about the path? Nope, we’re fucked on that:

https://overflow.ocus.top/exchange/webmasters/questions/90339/why-are-urls-case-sensitive

OTOH, sometimes we get lucky

Ultimately a stupid decision by the QR designers indeed. Hence the cross-posting to !asshole_crappy_design@slrpnk.net. The bulkier the text, the more useful it is to use the smaller char set. But the bulkier it is, the more unpleasant it is to read all uppercase.

    • evenwichtOPEnglish
      2·
      23 小时前

      see the other comments. pdflatex crashes when fancyqr is overworked, which I’ve seen happen when exceeding just 2 qr codes. There is also a typesetting problem w/big codes.

      Even when it doesn’t crash the compiler, it’s very slow. None of the QR pkgs are sophisticated enough to store the computed result and reuse it from one compilation to another.

  • pmjvEnglish
    1·
    23 小时前

    what’s the benefit of this? why should i care how big my qr code is?

    • evenwichtOPEnglish
      7·
      23 小时前

      You would care in some situations. Someone needs codes to be scannable from a long distance: https://hachyderm.io/@dolanor/117079618531657267

      I sometimes produce a document that is littered with codes. If the qrcodes are small enough, they can be in the doc close to where they are referenced. The bigger they are, the more intrusive they are to typeset around. If you are doing a bilingual doc with a different lang on either side of the QR code, It’s harder to manage a big code aesthetically. Then we are forced to consider moving all the QR codes to the last page in a references section – which is a trade-off because it means the reader must track down the right code for the reference they want to follow.

      QR encoding is computationally intensive. When I use the fancyqr package (which uses colors), I can only get away with 2 QR codes per document or latex crashes.

      Consider artwork as well. A stained glass worker really needs to keep the labor of cutting glass to a minimum and has a strong incentive to have a reduced number of bits. But then it’d be a shame to do a lot of labor to get a stained glass QR code that yields all uppercase text.

      So the poor decision to use all uppercase for the smaller charset impacts in several unpredictable ways. That is, you cannot predict all the circumstances that small QR codes are needed. But they could have predicated that all uppercase is less useful than all lowercase.

      • pmjvEnglish
        3·
        23 小时前

        Thanks for the comprehensive answer!