Region of interest feature does not work for non-square aspect ratios(!)

[xc212]

Expected behavior:

• QR code should scan if it is framed by the rect of interest with a small margin

Found behavior:

• QR code does not scan unless it is significantly smaller than the rect of interest

Steps to reproduce:

• Modify example so that the preview is full screen. (To do this I deleted all constraints on it and used the autoresizing mask to cover all of the superview.)
• Modify the region of interest so that it appears approximately square even though the view is non-square
• Start scanning a QR code from up close, then zoom out
• It will be a while before the region detects the QR code - the QR code is only detected at scales much smaller than the region displayed (see image)

^ this is the maximum scale I could get the QR code to scan with, starting from a close zoom

Tested on iOS 13 with iPhone X

[steventnorris-40AU]

Has there been a solution for this? I'm experiencing this as well. If I pull the phone really far away so the QR code is teeny tiny, it scans. Anything other than that will not work. My scale ends up being much smaller than what @xc212 experienced, using an iPhoneX.

[steventnorris-40AU]

Also, @xc212 if you don't use a rectOfInterest, it should scan fine at any size, which is my workaround for now. It seems the interest rectangle is done as a percentage of the screen, so getting a square might not be possible anyhow. This seems to be an issue with certain phone resolutions as well, so it's possible the drawn interest area and the actual area of the image being checked differ.

[ddaddy]

I'm having this same problem. If I don't use rectOfInterest then a qrcode will scan at any size. If I add a rectOfInterest the qrcode needs to be significantly smaller than the rectOfInterest for it to scan.

[mirekkukla]

The underlying seems to be that the rectOfInterest dimensions, when it comes to drawing the visual helper lines, assume your phone is in portrait orientation. Behind the scenes, though, when it comes to actually detecting the bar code, the given rectOfInterest dimensions are read as if your phone was in landscape orientation.

This is why a square area of interest works: the 'displayed' rectangle matches the detection region.