Client-side QR code generator with SVG output | Hacker News Reader

Client-side QR code generator with SVG output

fietkau.software

176 pointskentbrew31 comments

One of my favorite components from the open source web components library Shoelace is the QR code generator: https://shoelace.style/components/qr-code

This looks great! Wish I had it a few months ago instead of having to use qr-code-styling[0] which was a bit of a pain.

I remember it was around the same time that Obsidian got native callouts, so my notes for that project are all colourful & contain valuable admonitions like this:

```

> [!todo]

> That feeling when you're wasting hours of your life trying to make something you know is abandonware work just because it looks nice. There should be a word for that feeling. In Danish or Japanese. Or German.

```

[0]: https://github.com/kozakdenys/qr-code-styling

How about: fröbelen

https://nl.m.wiktionary.org/wiki/fr%C3%B6belen

Roughly means: To be creatively busy for fun

or a phrase, like "beating off a dead horse"

Yikes. That does not mean what you think it does in my locale.

The phrase would be "flogging a dead horse".

There’s an English word for it: art.

If that’s too broad, try https://en.m.wikipedia.org/wiki/Autotelic

If you're looking for a non web QR generator with lots of options try Zint. https://www.zint.org.uk/ It's the only option I have found that doesn't seem to lock out any features. You want to control the error correction? Got it. Render in color? No problem. Batch convert 1000 lines of text into 1000 individual images. It took less than a second. It even does Datamatrix and other non QR encodings.

USE THIS SOFTWARE AND LEARN FROM MY MISTAKE:

We made a cute Christmas video to include in our card this year. My wife created a QR code from a random website and included it in the card as a picture. It linked to our video. We sent all of the cards out. People loved it.

... except we got an email from the QR code company about a week before Christmas. We went over our "free" click (the QR code went through their URL shortener). If we wanted to keep the QR code active we had to pay $20/mo.

We got absolutely fleeced. Never again. Control the URL and make the QR image yourself.

I've spotted this on several large events on setup day, explained how fucked they'll be in a few days and showed them a safe QR code generator. Usually it was just signage and they could reprint the QR code and glue it over the bad one, but one of them had printed hundreds of leaflets with the event schedule and I think they just ended up paying because even a year of "QR ransom" was cheaper than overnight printing and shipping.

My other favourite QR-code related fuckup is designers trimming the quet zone to just 1 module "because the white border looks ugly" and not checking if the codes are scannable. That and light-on-dark codes, which according to the standard don't exist, but most scanner apps can handle them these days thanks to endless complaining by designers.

Yep, came here to make a similar comment.

My sister used some random free QR generator to open your email app with a “to/subject” filled out. There was no sign up and she didn’t know to check to QR code itself. Instead of being a normal QR code (QR codes support the email case directly, as part of the “spec”) it was a link to the QR company’s website that immediately bounced you to the the right url to open your email.

After a month or so they emailed her (using the email address she entered for the code) and told her to pay up or the code would stop working.

These people are scum. Make it clear it’s not a standalone QR Code (and there are potential upsides to this, to be fair, like updating where the qr code points) and don’t bait and switch.

Clever grift. I am surprised I have not heard more stories about “free” web tools utilizing some kind of similar monetization trick.

Thank you for building this wonderful UI on top of my library!

If you stumbled upon this looking for the smallest QR code JS library, it's probably LeanQR [0]. It's under 10kb minified and 5kb compressed.

[0] https://qr.davidje13.com/

While I didn't never specifically optimize it for the size (unlike some libraries I do), my very old qr.js library [1] seems to be smaller than that, less than 9 KB minified and 4 KB gzipped in my brief testing.

I should note that qr.js never supported the correct Kanji encoding and optimal encoding based on dynamic programming, but otherwise it is functionally complete and I think it can't get much larger than that. There are lots of rooms to cut from there and I will say 5 KB is a fair estimate for the minified size after modest but correctly guided size optimization.

[1] https://github.com/lifthrasiir/qr.js (predates the modern JS, but surely more popular than LeanQR I believe)

Huh. Didn't run in to it when I was searching for libraries. It appears to be just 350 bytes larger than LeanQR when gzipped.

I found that Anthony Fu's QR Toolkit is a great alternative: https://qrcode.antfu.me/

Pretty great example, but I was bummed to see that Error Level is missing. I like to create easy codes with low error correction.

Use mine - more technical options, fewer graphical options. https://www.nayuki.io/page/qr-code-generator-library

I've been using this library: https://www.npmjs.com/package/qrcode.

Works great and it does svg too. There are a few alternatives to this around as well but this one seems good enough.

Isn't this one of those rare occasions where bitmap file format is more optimal for storing output?

At 1 module = 1 pixel resolution, it definitely is, although a gzipped SVG gets you closer than you'd expect. The main problem with images is scaling: unless you can force the image to scale "without" interpolation, you'll get a blurry unscannable mess. If you increase the resolution enough to be crisp on a modern high-res display, at some point, SVG becomes more efficient. I did some experiments on this a few years back, but can't find the results right now.

A even if you can force nearest-neighbour interpolation (in CSS this is only possible since 2015 in Chromium and even later in Firefox), the result still won't be perfect at non-integer scales (see [0]). Other use-cases (like PDF files IIRC) don't give you the option to force scaling modes at all, so drawing them with vector paths is the only option to make them crisp.

[0] https://codepen.io/robinrendle/full/EaOJeq/

With SVG you can render directly on the page, no extra file involved.

You can also do that with png https://stackoverflow.com/a/8499716/1595060

You can try https://app.y.gy. It's not a library, but they have an API for link-shortening and QR Code Generation.

"The demo on this page combines Project Nayuki’s QR Code generator library (a multi-language open source project that can, among other things, perform the conversion of text into raw QR code data) with my own QRSVG project, which can turn a QR-like two-dimensional boolean data map into an efficient vector description of its own visualization by tracing the contours of contiguous shapes."

For some reason in my phone camera - "Open in browser" is not showing up if background is dark.

The original spec didn't allow for anything but "dark on light" codes. The official spec has been amended a bunch of times, but it's not always clear what version of the QR code spec an app uses. If it stuck with the original from 2000, it can't scan inverted codes. The spec itself has been amended in 2006, but the full spec is proprietary and needs to be bought, so not everyone may have updated their code if they have the old spec on a network share somewhere.

What phone and software? Old libraries looked for the contrast of black-on-white (not white-on-black), but I thought that was a solved problem now.

iPhone 15 pro, iOS 17.6.1

Black background, white foreground works fine on my iPhone 13 mini.

For local use, this Python library can generate SVGs with QR codes: https://github.com/lincolnloop/python-qrcode

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