QR codes not getting recognized if it has a background

[nathanfallet]

Description of the problem:

My app is generating a QR code on a background. The code is well recognized by my iOS app, but on Android, only the code without background works.

Exemple : This one is not getting recognized: While the raw code, is:

Which library version are you using? 4.3.0

Which phone/tablet are you using, and which Android version does it run? (e.g. Samsung Galaxy S5, Android 5.0) Tested on my Wiko running Android 5.0, on my girlfriend Xiaomi (don't know the Android version but it's something recent), and on the emulator (Pixel 3a) running Android API 31.

Does the same happen on other devices or an emulator? It happens on all the device I tested and mentioned above.

Can you reproduce the issue in the sample project included with the library? If not, can you provide your own sample project or sample code that produces this error? Yes, using the two images I uploaded above. One is getting recognized while the other not.

In the case of an error do you have a stack trace or adb logs? There is no error. Nothing happens while pointing the code on a background.

[rkistner]

The standard scan mode is for black / dark foreground on a white / light backround.

To handle a case like this, use the "Inverted" scan mode.

[nathanfallet]

@rkistner Is there a mode in which both can be recognized? Because both can be used by users. And I have my iOS app handling both of them too, so I would like my Android app to do the same.

[rkistner]

Yes, you can use the MIXED_SCAN mode:

https://github.com/journeyapps/zxing-android-embedded/blob/2324a5403e8b89b66631977b357d1b998f1caf7e/sample/src/main/java/example/zxing/MainActivity.java#L60

[nathanfallet]

Thanks!