Can't scan some PDF417 barcodes

[seadowg]

Some barcodes (sent to us privately) on states IDs can't be scanned in the latest version (v2025.3.1) of Collect. This appears to be a regression as they can be scanned in v2025.2.0-beta.6. @seadowg can reproduce easily using his Pixel 6a.

Problem
It’s difficult to scan wide barcodes because the square viewfinder forces users to get very close to capture enough detail while also fitting the full barcode in frame. The square shape doesn’t always match the proportions of barcodes.

Hotfix solution

• Add landscape with full-screen viewfinder: Keep the current square viewfinder as-is to avoid disruption, and add a landscape mode with a full-screen viewfinder so it's easier to scan the entire barcode. A FAB lets the user switch between these modes without rotating.
• No flashlight button in landscape: We won't have the flashlight button on landscape. The user would need to turn that on in portrait mode.
• Rotate to go back to portrait mode: To get out of landscape mode, they can simply turn the device or press the rotate button.
• Inform the user they can rotate: To make the rotating option clear, we’ll add a prompt 10s after landing on the viewfinder in portrait mode (adding a label to the FAB expanding it to an "extended FAB"), nudging users that they can rotate the device.
• Keep orange border: We can still keep the orange state and bring the icon into the frame in landscape so it's clear when it isn't working.

Figma

[seadowg]

@dbemke it looks like I'm able to scan if I make the viewfinder (and the area we filter barcodes within) fill the whole screen. I'll send you an APK on Slack to see if you get the same results.

[WKobus]

@seadowg Should we do regression for barcode scanning in this APK or just test the case with scanning mentioned PDF codes

[seadowg]

@WKobus just check that it's as easy to scan that specific PDF417 barcode as in v2025.2.0-beta.6.

[dbemke]

Results of testing the ID barcode:

Pixel 7a Android 16 - first scan neutral, following scans fast
Pixel 3a Android 12 - Scans horizontally and vertically, a lot of leaks, but no crashes
Redmi 9T Android 10- unable to scan (no orange frame) both in horizontal and vertical
Pixel 6a Android 16 - Easy to scan
Samsung Galaxy M23 Android 14 - Unable to scan vertically, easy horizontally
Samsung Galaxy M12 Android 11 - Unable to scan vertically, easy to scan horizontally
Redmi 7 Android 10 - Unable to scan vertically, easy to scan horizontally
Nexus 5x Android 8.1 - easy to scan both vertically and horizontally

8 devices checked: 4 devices worked well (Pixels and Nexus Android 8.1), 1 devices isn't possible to scan, 3 devices scan only horizntally

[seadowg]

@alyblenkin @grzesiek2010 I think we can basically conclude that the problem is needing to get close enough to the barcode for the camera to pickup detail while also fitting the barcode within the view finder - that's hard given how wide the barcode is and the square shape of the barcode. Increasing the size of the view finder helps, but I find on the Pixel 6a that I usually have to scan in landscape.

A couple of ideas:

1. Allow rotation and show a (landscape) rectangle view finder in landscape. This makes it much easier to scan, but makes it hard to show the prompt and flashlight button.
2. Make the view finder taller than it is wide (a portrait rectangle) if there's room (like in the full screen scanner). This doesn't make it any easier to scan portrait, but you can quickly flip the phone (which doesn't rotate the display) to fit the barcode in close enough to fit.
3. Allow a question level opt-in to remove the view finder entirely (and filtering of things otuside it).

Let me know if you have preferences between those, or if you have any alternatives.

[lognaturel]

One more alternative I’d like for us to consider:

Use the whole window for scanning, once a code bounding box is identified, show that box with the orange color. Once it’s scannable, show the green color. This would balance making scanning as easy as possible with making sure the user knows what is being scanned. If I recall correctly that’s what the ML Kit Android demo does. I can link to that if helpful.

1 devices isn't possible to scan, 3 devices scan only horizntally

How does that compare to 2025.2 with ZXing?

[seadowg]

Use the whole window for scanning, once a code bounding box is identified, show that box with the orange color. Once it’s scannable, show the green color.

The view finder filtering also really helped us with removing partials (#6784), so we'd need to be careful about regressions there as well as making sure to redesign for full window scanning. It does make me think that there's probably a whole section of fuzzier "bounding box" approaches we could experiment with like requiring "most" of the barcode in the view finder etc. However, I would like to see if we can get a smaller change out as a hotfix first and I don't think we should rework our current approach if it still feels like the best flow for the majority of barcodes.

EDIT: @lognaturel is going to have an experiment with scanning partials with the APK I sent @dbemke earlier (#6913 (comment)) and report back.

[lognaturel]

a lot of leaks

This is Leak Canary reading memory to try to detect leaks. I don't see any actual leaks detected though.

@lognaturel is going to have an experiment with scanning partials with the APK I sent @dbemke earlier
The view finder filtering also really helped us with removing partials (#6784)

Not as far as I can tell. I have been very easily been able to reproduce partial scans on some of our prior builds and even on the ZXing versions. I've tried really hard with the debug build that makes the bounding box the whole screen and I have not been able to get a partial or incorrect scan.

I think the only thing the bounding box helps with is if there are multiple barcodes close together. That's definitely a possibility (in fact our Insiders call speaker today showed a roster sheet with many barcodes) but I don't know how we want to balance that with making single codes easier to scan.

For what it's worth, the experience with the full screen bounding box turning yellow then green feels really nice to me too. Maybe we could consider a hybrid where we keep the current square bounding box in portrait and when users turn to landscape the bounding box maxes out the screen (no flashlight or prompt).

[alyblenkin]

I think the only thing the bounding box helps with is if there are multiple barcodes close together. That's definitely a possibility (in fact our Insiders call speaker today showed a roster sheet with many barcodes) but I don't know how we want to balance that with making single codes easier to scan.

Yes, I was going to make this point as well! We need to find a balance.

Maybe we could consider a hybrid where we keep the current square bounding box in portrait and when users turn to landscape the bounding box maxes out the screen (no flashlight or prompt).

Yes, this might be a nice balance. I think rotating your phone to expand the bounding box makes a lot of sense. It would be great to still have the flashlight prompt if it's dark, but I guess they could also turn it on in portrait and it stays on?

I could mock up what it could look like if we kept it @seadowg? I'm thinking a floating button could work.

[lognaturel]

With my Pixel 3a and the debug build with the full screen bounding box, I can scan the South African driver's license from the recent forum post when in landscape. I gave up in portrait after 30s.

I cannot scan the code that was privately sent after a minute of trying in landscape. When I turn the brightness and contrast up on my monitor showing the code that was privately sent, it's very easy to scan in landscape with the full screen bounding box.

[dbemke]

How does that compare to 2025.2 with ZXing?

Zxing in Collect v2025.2.0

Redmi 9t Android 10 - difficult to scan, wrong results 11sec
Pixel 7a Android 16 - difficult to scan, correct and wrong results 6sec, 10sec
Nexus 5x Android 8.1 - difficult to scan, correct results 10sec
Samsung Galaxy M23 Android 14 - first scan neutral(7s), next scans easy(1-3s), correct results
Pixel 3a Android 12 - easy to scan (2-4 second), first time partially, next scans correct results
Pixel 6a Android 16 - ~5 sec to scan, mostly correct results, few wrong
Samsung Galaxy M12 Android 11 - ~10 sec to scan, wrong results
Redmi 7 Android 10 - 13 sec to scan, wrong results
Alcatel Android 10 - difficult to scan(more than 15s), wrong results

9 devices checked: on all devices it is possible to scan