@lionowl #LÖWEN

A Recursive QR Code

https://shkspr.mobi/blog/2025/03/a-recursive-qr-code/

I've been thinking about fun little artistic things to do with QR codes. What if each individual pixel were a QR code?

There's two fundamental problems with that idea. Firstly, a QR code needs whitespace around it in order to be scanned properly.

So I focussed on the top left positional marker. There's plenty of whitespace there.

Secondly, because QR codes contain a lot of white pixels inside them, scaling down the code usually results in a grey square - which is unlikely to be recognised as a black pixel when scanning.

So I cheated! I made the smaller code transparent and gradually increased its opacity as it grows larger.

I took a Version 2 QR code - which is 25px wide. With a 2px whitespace border around it, that makes 29px * 29px.

Blow it up to 2900px * 2900px. That will be the base image.

Take the original 25px code and blow it up to the size of the new marker, 300px * 300px. Place it on a new transparent canvas the size of the base image, and place it where the marker is - 400px from the top and left.

Next step is creating the image sequence for zooming in. The aim is to move in to the target area, then directly zoom in.

The whole code, if you want to build one yourself, is:

#!/bin/bash#   Input fileinput="25.png"#   Add a whitespace borderconvert "$input" -bordercolor white -border 2 29.png#   Upscaled image sizeupscaled_size=2900#   Scale it up for the baseconvert 29.png -scale "${upscaled_size}x${upscaled_size}"\! base.png#   Create the overlayconvert -size "${upscaled_size}x${upscaled_size}" xc:none canvas.pngconvert "$input" -scale 300x300\! 300.pngconvert canvas.png 300.png -geometry +400+400 -composite overlay.png#   Start crop size (full image) and end crop size (target region)start_crop=$upscaled_sizeend_crop=350#   Zoom-in target position (top-left corner)target_x=375target_y=375#   Start with a completely opaque imageoriginal_opacity=0#   Number of intermediate imagessteps=100for i in $(seq 0 $((steps - 1))); do    #   Calculate current crop size    crop_size=$(echo "$start_crop - ($start_crop - $end_crop) * $i / ($steps - 1)" | bc)    crop_size=$(printf "%.0f" "$crop_size")  # Round to nearest integer    #   Keep zoom centered on the target    crop_x_offset=$(echo "$target_x - ($crop_size - $end_crop) / 2" | bc)    crop_y_offset=$(echo "$target_y - ($crop_size - $end_crop) / 2" | bc)    #   Once centred, zoom in normally    if (( crop_x_offset < 0 )); then crop_x_offset=0; fi    if (( crop_y_offset < 0 )); then crop_y_offset=0; fi    #   Generate output filenames    background_file=$(printf "%s_%03d.png" "background" "$i")    overlay_file=$(printf "%s_%03d.png" "overlay" "$i")    combined_file=$(printf "%s_%03d.png" "combined" "$i")    #   Crop and resize the base    convert "base.png" -crop "${crop_size}x${crop_size}+${crop_x_offset}+${crop_y_offset}" \            -resize "${upscaled_size}x${upscaled_size}" \            "$background_file"    #   Transparancy for the overlay    opacity=$(echo "$original_opacity + 0.01 * $i" | bc)    # Crop and resize the overlay    convert "overlay.png" -alpha on -channel A -evaluate multiply "$opacity" \            -crop "${crop_size}x${crop_size}+${crop_x_offset}+${crop_y_offset}" \            -resize "${upscaled_size}x${upscaled_size}" \            "$overlay_file"    #   Combine the two files    convert "$background_file" "$overlay_file" -composite "$combined_file"done#   Create a 25fps video, scaled to 1024pxffmpeg -framerate 25 -i combined_%03d.png -vf "scale=1024:1024" -c:v libx264 -crf 18 -preset slow -pix_fmt yuv420p recursive.mp4

blog! “A Recursive QR Code”

I've been thinking about fun little artistic things to do with QR codes. What if each individual pixel were a QR code?

There's two fundamental problems with that idea. Firstly, a QR code needs whitespace around it in order to be scanned properly.

So I focussed on the top left positional marker. There's plenty of whitespace there.

Secondly, because QR codes…

Read more: https://shkspr.mobi/blog/2025/03/a-recursive-qr-code/
⸻
#art #qr #QRCodes

@psuPete Recommends - Weekly highlights on cyber security issues, 03/01/25 https://www.llrx.com/2025/03/pete-recommends-weekly-highlights-on-cyber-security-issues-march-1-2025/ Five posts from this week: #Trump has purged government websites; The Wayback Machine trying to preserve the record; Turn off your read receipts. They’re a #security risk; You can now easily remove personal info from #Google Search results; Google plans to end #SMS verification in favor of #QR codes; and #Verizon isn’t doing enough to protect customers from #robocall scams. #cybercrime #privacy

Did you know that you can invoke Siri Shortcuts by scanning a QR code? The shortcut has to exist on the device on which you scan the QR code, of course. The URL you have to encode is:
shortcuts://run-shortcut?name=<insert shortcut name here>
The shortcut name can even contain spaces and they don’t have to be encoded as %20, easy peasy.
One of my use cases: Enable/Disable the guest wifi by scanning a QR code that sticks on a door.
#qrcode #sirishortcuts #ios #iphone #automation #workflow #qr

Making easy-to-scan #QR codes is an under-appreciated skill.

Not using super long URLs from some verbose CMS is a good start, but there's more tricks:

https://shkspr.mobi/blog/2025/02/why-are-qr-codes-with-capital-letters-smaller-than-qr-codes-with-lower-case-letters/

為什麼帶大寫字母的 QR 碼比小寫字母的 QR 碼要小？- Terence Eden's Blog
➤ 大寫字母在 QR 碼中的優勢
✤ https://shkspr.mobi/blog/2025/02/why-are-qr-codes-with-capital-letters-smaller-than-qr-codes-with-lower-case-letters/
文中探究為何帶大寫字母的 QR 碼比小寫字母的 QR 碼更小的原因，並解釋了這背後的技術原理。
+ 看完這篇文章後，對 QR 碼背後的技術原理有更深入的瞭解，很有趣！
+ 原來大小寫字母在 QR 碼中使用有這麼多差別，學到了一個小技巧！
#QR 碼技術

Fun fact: #QR codes can be either alphanumeric mode or binary mode. Alphanumeric mode is all-caps and is more concise, so your URL will generate simpler QR codes when it is entirely uppercase.

Here's a very detailed explanation by Terrence Eden, @blog: https://shkspr.mobi/blog/2025/02/why-are-qr-codes-with-capital-letters-smaller-than-qr-codes-with-lower-case-letters/

blog! “Why are QR Codes with capital letters smaller than QR codes with lower-case letters?”

Take a look at these two QR codes. Scan them if you like, I promise there's nothing dodgy in them.

Read more: https://shkspr.mobi/blog/2025/02/why-are-qr-codes-with-capital-letters-smaller-than-qr-codes-with-lower-case-letters/
⸻
#qr #QRCodes

Russian hackers target Signal accounts in growing #espionage effort

Google’s Threat Intelligence identified rise in #Russian state-backed #hacking aimed at compromising #Signal #messenger

Primary technique involves exploiting Signal’s linked devices feature, allowing users to connect additional devices to their accounts

Hackers create malicious #QR codes when scanned, link a victim’s Signal account to a hacker device

https://kyivindependent.com/russian-hackers-target-signal-accounts-in-growing-espionage-effort/

Maybe the new #DMA #NFC #interoperability measures for #iOS will lead to a better way for train companies to share e-tickets with customers than #QR codes, which need to be scanned by gates… which simultaneously try to take a card payment from your i#Phone

You know what though, #QR codes are actually pretty neat.

As a kid, I never expected that one day we'd be able to just slap 2953 bytes on the side of whatever object we want to slap 2953 bytes onto. Just, like, whatever bytes we feel like slapping that day.

TIL QR codes were inspired by the game of Go.

https://open.prodir.com/en/2021/06/bars-cars-and-go-the-story-of-the-qr-code/

Building a QR Code #HTML Web Component via https://mstdn.social/@scottjehl

https://scottjehl.com/posts/q-r

#Evil QR code!
This #QR #Code Leads To Two Websites, But How? https://hackaday.com/2025/01/23/this-qr-code-leads-to-two-websites-but-how/