Show the "sweet spot" for the scanner

[futurepaul]

Ideally we can show which part of the screen you're trying to get the QR code into, instead of just showing a big video. Bonus points for a little freeze frame when it finds one. Might involve some math, because we support so many viewports / aspect ratios.

[j0hncc]

IS there actually a sweet spot? If so I would like to see this too, if it would improve the usefulness of the scanner. I tried scanning an invoice the other day and finally gave up and used another wallet (strike I think) which scanned it instantly. To be fair the QR was on a relatively smaller phone model, but...

edit: mutiny 1.7.1 running on Samsung A53. Don't know the model of display phone but will find out.