Limit for data?

[rucksman]

I tried to generate a QR Code with around 144 strings, each consisting of 20 alphanumeric characters. Unfortunately this fails (downloaded PNG file is completely white). Is there a limit somewhere in the code? The German Wikipedia states that up to 4096 alphanumeric characters are possible in a QR Code, so my 2880 characters should work.

[lyqht]

Have you tried changing the error correction level for your use case? The longer your data, the lower you have to set the error correction level. Here's a good explanation I found about how the qr code size relates to the data length kozakdenys/qr-code-styling#104 (comment)

[rucksman]

Yes, error correction level is already at L. Which version of the QR code is used in mini-qr (https://www.qrcode.com/en/about/version.html)? Seems like a version lower than 33 is used, because from version 32 on downwards only 2840 or less alphanumeric characters are allowed. Ideally version 40 shouldbe used for maximum characters.