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Boosted by kornel ("Kornel"):
rebane2001@infosec.exchange ("Rebane") wrote:

i love seeing creative qr code designs, so i made this guide explaining what tricks you can (and can't!) do with qr codes while still keeping them very much readable

have fun and make cool stuff!!

(ADVANCED) Guide to (not) fucking up qr codes ...while still making them look cool asf! by Lyra Rebane (1) Just have the QR code as-is, works the best! (2) But leave some white padding, otherwise some scanners can't scan the code! (3) Recolor the code using a light and dark color! (4) But don't invert the colors, some scanners can't handle this. Everything tested with: GrapheneOS, Samsung, iOS, Binary Eye Page 1/4
(1) Depending on the error correction you can cover up to 30% of the data in the QR code. This will make the QR harder to scan, but it should still work on all scanners. (2) But this only applies to the data and ec (green). You can also cover one of the format info parts (yellow) (3) Counter-intuitively, it also only applies to entire codewords (bytes) at once. Therefore you should make sure to never mess up over 30% of the codewords, even by a single pixel! (4) For example, I added a sneaky one pixel thick worm onto this QR code, which makes it unscannable! (5) But this QR code I added that chonky snake with a pride scarf onto remains perfectly readable! Page 2/4
(1) To scan QR codes, scanners will first find the three locators (blue) and then use the zebras (red) to create a grid over the code. (2) This means that you can stretch, skew, or rotate your codes because the grid still stays intact! Don't go too overboard with this, as some scanners can't handle extreme transformations. Pretty much just make sure that straight lines can still be drawn! (3) However, transformations that don't retain the grid - such as bends - can make the QR code unreadable. Keep this in mind when putting your QR codes on curved real world objects, such as posts and pipes. (4) If you need to draw curved lines for a grid, the code cannot be scanned. Note: the GrapheneOS stock Camera app might struggle with certain skews/rotations Page 3/4
(1) QR code scanners use the grid to pinpoint the center parts of pixels, which means that the rest of the pixel does not matter! (2) This means that you can shape your pixels however you want, provided that the middle stays unchanged. (3) Or you can fill the rest of the QR code with a different image or even pure noise! Note that a QR code like this could break after resizing or image compression, so use with caution! (4) As with the other tricks, this reduces scannability, so make sure to test it with multiple devices, especially if you’re combining all of the tricks into one ultra QR code! (5) This example still scans, but may not work properly or reliably everywhere! Page 4/4