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/
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#art #qr #QRCodes

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

Ich habe ja keine Ahnung, und nur Chat nur hier von! ich frage mich aber, ob es #QRCodes gibt die so ziemlich ins „jenseits“ laufen und immer weiter. Es gibt einfach zu viele Cameras die ständig „on search“ sind. Macht so etwas Sinn?

Yo Dawg! I heard you like #games in #qrcodes so I'm adding a QR-Code reader to QR-Code games so you can scan QR-Codes while playing QR-Codes. #deadmeme #opensource #rewtro #WIP

(FAQ: Are monsters GFX, sounds, and data encoded in card's QR-Codes? A: Yes)

Die Landeshauptstadt Kiel warnt vor gefälschten Aufklebern zur Bezahlung von Parkgebühren. Es handelt sich dabei um einen QR-Code, der nicht zur offiziellen easypark-App führt.

Kieler Nutzer*innen sollten genauer hinschauen, ob die #QRCodes vertrauenswürdig sind. Gefälschte QR-Codes haben einen pinkfarbenen Rand und werden über den Original-QR-Code geklebt. In einem Verdachtsfall sollte die Polizei hinzugezogen werden.

Infos von Easypark
https://www.easypark.com/de/so-erkennst-du-betrug

Needless to say, don’t scan any random QR-codes you get spammed with here.

I'm always looking for interesting use cases for #QRCodes. This one certainly makes my list of cool: A #QR code based doorbell.
https://dingdongdoorbell.com/

Don’t know who needs to here this so I’ll say it loud.

DO NOT SCAN QR CODES

A friend did that a couple of days ago. It was on a machine in a car park to download their app. Except someone has replaced it and the first she knew was her bank letting her know they’d spotted fraudulent activity.

She was lucky and the bank stopped all the transactions and blocked her account. The next person might not be.