Doesn't detect white codes on dark backgrounds

[mircerlancerous]

It's becoming more common for QR codes to be printed in white instead of black, with dark backgrounds instead of white; the scanner cannot decode these it seems, at least not in my implementation. I've seen this recently on a pizza box and a promo poster, so I'm assuming it's not a fluke. Seem like it'd be pretty easy to add support by just inverting the canvas colour every third scan, or something like that.

[ioulian]

I have the same issue, we have white QR code on red background

[mircerlancerous]

@ioulian it would be great if you can upload a sample of your QR code.
For my part I have fixed this for my purposes by employing the change I recommended; this should really be implemented in the core decoding functions, so I won't do a PR with it. If you try it and it works or doesn't, add a comment here
zxing-browser.min.neg.zip