QR code detection in PDFs sometimes fails

[fhibler]

Hi,

the PDF upload of the EU COVID certificate (export from CWA) is only working if I rotate the PDF, so that the QR code is on the top right corner. It did not work with the default layout.

Error message being shown:
Could not find QR Code in provided file.

iPhone X
iOS: 15.2
Latest Safari w/ default settings
CWA: 2.15.1 (2)

[marvinsxtr]

I think the QR code is upside down there. In general, the QR code detection in PDFs seems to be kind of inconsistent. We already tried to optimize this but seem to have reached the limitations of the library we are using. Haven't found something better since.