Show HN: QR code renderer in a TrueType font

#1

Post by foodevl » Sun, Jun 28, 2026, 12:37 AM UTC

In the "Libre Barcode Project" discussion yesterday, 1bpp asked: "Is anyone willing to sacrifice their sanity for the sake of implementing a QR renderer as TTF hinting code?"

Yes. I had some tokens to burn and was curious... turns out, it's possible. This was put together by a mix of Gemini, GPT, and Claude (depending on which usage limits kept running out).

Show HN: QR code renderer in a TrueType font
qr.jim.sh

Re: Show HN: QR code renderer in a TrueType font

#2

Post by foodevl » Sun, Jun 28, 2026, 12:38 AM UTC

1bpp's comment suggesting this yesterday: https://news.ycombinator.com/item?id=48682460

Re: Show HN: QR code renderer in a TrueType font

#3

Post by WenboS » Sun, Jun 28, 2026, 2:02 PM UTC

This is absolute black magic. I never realized OpenType rules were powerful enough to render something as complex as a QR matrix inline.

Re: Show HN: QR code renderer in a TrueType font

#4

Post by bigboss2700 » Mon, Jun 29, 2026, 9:27 AM UTC

That's a wonderfully cursed idea.

Re: Show HN: QR code renderer in a TrueType font

#5

Post by 1bpp » Mon, Jun 29, 2026, 4:21 PM UTC

This is terrifying, great job!

Re: Show HN: QR code renderer in a TrueType font

#6

Post by red_hare » Wed, Jul 01, 2026, 6:44 PM UTC

Wow. This is so freaking cool.

Re: Show HN: QR code renderer in a TrueType font

#7

Post by lifthrasiir » Wed, Jul 01, 2026, 6:45 PM UTC

See https://github.com/jimparis/qr-font/blob/master/design.md for the actual design. As who have written a QR code encoder library... I'm in shock and awe.

Re: Show HN: QR code renderer in a TrueType font

#8

Post by layer8 » Wed, Jul 01, 2026, 6:49 PM UTC

Side question: Why is nobody making QR codes on web pages clickable (regardless if it’s an image or text-based)? Not every QR code represents a URL, of course, but many do. Maybe there should be a qrcode URL scheme that lets browsers behave the same way as a camera scanning a QR code.

Re: Show HN: QR code renderer in a TrueType font

#9

Post by giraffe_lady » Wed, Jul 01, 2026, 7:01 PM UTC

WenboS wrote: post #3

This is absolute black magic. I never realized OpenType rules were powerful enough to render something as complex as a QR matrix inline.

Font shaping rules are actually turing complete. An incredible amount of engineering effort has gone into this not being a total disaster everywhere at all times.

Re: Show HN: QR code renderer in a TrueType font

#10

Post by layer8 » Wed, Jul 01, 2026, 7:07 PM UTC

WenboS wrote: post #3

This is absolute black magic. I never realized OpenType rules were powerful enough to render something as complex as a QR matrix inline.

It’s basically Turing-complete: https://simoncozens.github.io/fonts-and-layout/features.html

Once something is Turing-complete, the magic turns from black to white. ;)