Add support for QR Model 2

[numericOverflow]

I have a couple cards that use model 2 QR codes, but it looks like the app only generates model 1 codes. They typically work, but some scanners a flakey and really seem to want that model 2 image.

Supposedly model 2 has better support for curved surfaces and distorted images, along with more data capacity (but we likely don't care about huge data payload).

http://www.qrcode.com/en/codes/model12.html

[brarcher]

The barcode support for this app comes from the zxing-android-embedded project, which in turn pulls from the zxing project. If the upstream zxing project were to add support and zxing-android-embedded were to pick it up, I'd gladly add support. Currently this app uses the latest release of zxing-android-embedded.

I encourage you to verify with the zxing test app here that it indeed does not support QR code v2. If it does not, kindly add a request to that project. If it does actually have support, let me know and I can help see if it is the zxing-android-embedded project which is missing support.

[numericOverflow]

@brarcher - I did try scanning these mode 1 & 2 QR codes with the xzing app, and they read just fine.

It looks like zxing library does support QR model 2 by passing a Map hints with "QR_VERSION":

• https://stackoverflow.com/questions/40649034/zxing-android-qr-code-mode-1-and-mode-2-type
• https://zxing.github.io/zxing/apidocs/com/google/zxing/qrcode/encoder/Encoder.html

[brarcher]

Oh, that sounds promising then. Thanks for looking into that.

So, what you are looking for is the app displaying QR model 2 codes. I think this is doable. I'll need to see how best to support it, as there currently is no plumbing in the app for hints.

Questions:

1. Do you know if QR model 2 is backwards compatible with QR model 1? That is, should a scanner for model 1 be able to read many or most model 2 codes?
2. How should the app allow one to enter a QR model 2 code? I should be able to generate both model 1 and model 2 codes to pick from when manually entering the code, but I'm curious if that is the expected way to add a model 2 card. I think when a code is scanned with the camera it would only say it is a QR code, but not mention it is a model 1 or 2.