Does not recognize linear barcodes in white on black

[staydry]

Hi! Great tool, thank you for developing it.

Noticed that it does not recognize linear barcodes in white on black background (some manufacturers use them making their black packaging more attractive): looks like it tries to read black stripes instead of white in such cases.

Affected types: EAN-13/8, UPC-A/E, Code-128/93/39, Interleaved 2 of 5, Codabar, PDF417, etc.

Regards!

[markusfisch]

Hi, and thanks for filing an issue about this! 👍

This is a limitation of ZXingCpp, the barcode library this app is using. The standards of the affected types don't include negated versions, so support for this was excluded.

[staydry]

Thanks for feedback! I have notified ZXingCpp guys on this issue so may be they will implement inverted barcodes processing one day.

[staydry]

Further to above

Since inverted 1D barcodes use is not a widespread practice they are not going to implement automatic detection of those yet but mention that such a detection can be arranged on application side -

----quote----
If you need to support those, you may easily do so by inverting the image before you pass it to zxing-cpp. In that case, I'd recommend to set ReaderOptions::tryInvert to false, to not do unnecessary extra work for any 2D symbology that actually supports inverted colors.
---unquote---

Just for case you find that worthwhile in the future.