fix: 3674 - simplified the barcode scan with native solution

[monsieurtanuki]

Deleted files:

• tons of them

New file:

• smooth_qr_view.dart: QR View.

Impacted files:

• app_test.dart: removed reference to specific scanner
• basic_test.dart: removed reference to specific scanner
• camera_helper.dart: removed now useless code
• camera_scan_page.dart: HIGHLY simplified the code with the use of new class SmoothQRView
• constant_icons.dart: added a "camera flip" icon
• labeler.yml: removed reference to now removed files
• main.dart: removed reference to specific scanner
• main_fdroid.dart: removed reference to specific scanner
• main_google_play.dart: removed reference to specific scanner
• main_ios.dart: removed reference to specific scanner
• pubspec.lock: wtf
• pubspec.yaml: added qr_code_scanner; removed reference to specific camera and specific scanner
• scan_page.dart: simplified the display - camera on top, carousel on bottom
• user_preferences_dev_mode.dart: removed reference to camera post frame callback duration and scan area settings
• user_preferences_settings.dart: removed reference to file/byte camera mode computation setting

What

• The goal is to get rid of the flutter camera package (which does not give entire satisfaction) for the barcode scanning.
• The solution here is to use native packages.
• The existing flutter package with native code I found (qr_code_scanner) is based on ZXing.
• Very interesting side-effects:
  • the app finally works on my smartphone
  • the code is hugely simplified
  • the code runs much faster - at least for developers waiting much too long during the flutter run
• The UI is slightly different: the camera preview is now restricted to the top part of the screen.
• If later we need to implement MLKit as well, we need to implement a solution similar to whatever qr_code_scanner provides: a single widget, with camera based on native libraries.
• Of course this PR should be tested on a large number of devices.

Screenshot

dark mode	light mode

Fixes bug(s)

• Fixes: Pixelated camera #3674
• Fixes: I can't scan anything anymore #3670
• Fixes: Can't Scan item from camera properly ( Blur ) #3664
• Fixes: IllegalStateException: CameraDevice was already closed #3521
• Fixes: Barcode Scanner with fdroid build does not work #3427
• Fixes: _CastError: Null check operator used on a null value #3349
• Fixes: StateError: Bad state: Cannot add new events after calling close #3348
• Fixes: LateError: LateInitializationError: Field '_mainIsolate@2150453397' has not been initialized. #3347
• Fixes: Camera crashes the app (Samsung) #2917
• Fixes: The app does not work on Monsieur Tanuki's test phone #2849
• Fixes: OutOfMemoryError: Failed to allocate a 3686736 byte allocation with 119544 free bytes and 116KB until OOM, max allo... #2548

Part of

• [Tracker] Make the app lighter #3669

[codecov-commenter]

Codecov Report

Merging #3694 (07f41af) into develop (f2ede98) will increase coverage by 0.44%.
The diff coverage is 1.14%.

@@            Coverage Diff             @@
##           develop   #3694      +/-   ##
==========================================
+ Coverage     9.34%   9.79%   +0.44%     
==========================================
  Files          272     264       -8     
  Lines        13722   13010     -712     
==========================================
- Hits          1283    1274       -9     
+ Misses       12439   11736     -703     

Impacted Files	Coverage Δ
packages/smooth_app/lib/helpers/camera_helper.dart	0.00% <0.00%> (ø)
...b/pages/preferences/user_preferences_dev_mode.dart	0.00% <ø> (ø)
...b/pages/preferences/user_preferences_settings.dart	10.30% <ø> (+0.46%)	⬆️
...es/smooth_app/lib/pages/scan/camera_scan_page.dart	2.56% <0.00%> (+2.11%)	⬆️
packages/smooth_app/lib/pages/scan/scan_page.dart	3.07% <0.00%> (-1.83%)	⬇️
...ages/smooth_app/lib/pages/scan/smooth_qr_view.dart	0.00% <0.00%> (ø)
packages/smooth_app/lib/themes/constant_icons.dart	53.84% <0.00%> (-9.80%)	⬇️
packages/smooth_app/lib/main.dart	14.16% <25.00%> (+0.45%)	⬆️

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[teolemon]

I'd really like to have a thorough discussion about this, it's the 3rd time we change scanner, but now we're in production. I've added elements to the Barcode Scanning document.
https://docs.google.com/document/d/1nxjyZD8NKM28w1J5LPhMybIRiw1t-31gB3mq39XtFxw/edit#
Can we schedule a discussion sometime this week ?

[monsieurtanuki]

@teolemon Please set an appointment and tell me a day in advance.

Additional thoughts...

The previous MLKit implementation:

• was too embedded in the Smoothie code; it should be a black box from Smoothie's perspective, just a widget with a callback
• was partly hidden in another github repository; as a dev with limited understanding of github I have no idea where the code is. As a consequence, I have no way to challenge it or to work on it.
• was not stable and provoked tons of sentry logs, which made sentry reports useless
• never worked on my smartphone, and more generally was notoriously problematic with low-end devices because of memory

To me, those are only nice-to-haves:

• immersive fullscreen
• best decoder
• in all directions

My recent work on the barcode scanner provided me with food for thought.
The most practical way would be to build our own "scan barcode" widgets, away from Smoothie:

• based on a native, camera or cameraX visual layer
• calling either zxing or mlkit
• and in the end a callback for each new barcode

With those widgets we'd be then able to say something like that in Smoothie:

• for ios, native and mlkit
• for google play, native (then cameraX) and mlkit
• for fdroid, native (then cameraX) and zxing

If I started this PR it was because:

• there were recent pending issues (a dozen would be closed, including several P0s)
• I had no idea how to fix MLKit
• I had nothing to lose as it never worked on my smartphone anyway

If someone else could fix the P0 issues I referred to while keeping MLKit I'd be more than happy.

[natrius]

Because its mentioned above - i installed 4.5.0 now and tried it: #3427 is not fixed unfortunately. The camera seems to refocus every 2-3 seconds but thats it. Thanks for your efforts!

[monsieurtanuki]

@natrius This PR was not merged eventually.
Thank you for your comment: we definitely need to fix that barcode scan / camera preview issue.

[M123-dev]

Because its mentioned above - i installed 4.5.0 now and tried it: #3427 is not fixed unfortunately. The camera seems to refocus every 2-3 seconds but thats it. Thanks for your efforts!

What I am wondering right now, is this refocusing a "big" problem, because we use the same camera implementation on ever store only the scanning engine is changed

[monsieurtanuki]

@M123-dev That's the whole idea: being able to split in OOP a generic widget, camera preview and barcode scan algorithm.