fix: correct android preview orientation #1329

navaronbracke · 2025-02-14T08:48:26Z

This PR adjusts the preview orientation for Android.

Previously the formula was not entirely correct.

… & fix formula

navaronbracke · 2025-02-14T13:43:33Z

cc @@camsim99 I applied your latest patch changes in here to test it, too.

This now works correctly for devices that have handlesCropAndRotation set to false (so roughly API >= 30).
However, the preview is incorrectly rotated for devices that have handlesCropAndRotation set to true.
I did not see any changes between Flutter 3.27 and 3.29 when testing this.

Since the code path for handlesCropAndRotation set to true is equal to the old implementation (pre SurfaceProducer), I think that that behavior is a separate bug? With handlesCropAndRotation: true I would have expected the preview to always be rotated correctly automatically, but apparently that isn't the case.

I'll also need to test this change on a device that is naturally landscape oriented, I have not verified it there yet.

camsim99 · 2025-02-14T17:09:20Z

Thanks for testing! What device are you testing on for handlesCropAndRotation is true? And is it an emulator? Either way, I agree; that would be a separate bug that is not camera-specific.

I don't know if naturally landscape oriented devices will work yet but if it does, that'd be a happy surprise, so let me know.

navaronbracke · 2025-02-14T17:18:32Z

I was testing on these devices

Android 10: https://www.gsmarena.com/motorola_one_(p30_play)-9310.php
Android 13: https://www.gsmarena.com/samsung_galaxy_xcover6_pro-11600.php

I did not test emulators, since I know that those might not be working properly yet.
I'll try to see if I can find a tablet to test on as well.

navaronbracke · 2025-02-14T17:23:29Z

Also, the Motorola had its Vulkan support fixed (Adreno 5xx GPU) in Flutter 3.29, but I doubt that that is related, as it still reports handlesCropAndRotation: true, which indicates it is using the old API under the hood.

navaronbracke · 2025-02-17T08:36:48Z

android/src/main/kotlin/dev/steenbakker/mobile_scanner/MobileScanner.kt

@@ -621,7 +638,7 @@ class MobileScanner(
        }
        val paint = Paint().apply { colorFilter = ColorMatrixColorFilter(colorMatrix) }

-        val invertedBitmap = Bitmap.createBitmap(bitmap.width, bitmap.height, bitmap.config)
+        val invertedBitmap = Bitmap.createBitmap(bitmap.width, bitmap.height, bitmap.config!!)


This is a change that wasn't surfaced when using Kotlin 1.7, hence the bump to Kotlin 1.8. For some reason the compiler now checked for null specifically for this case (and probably others but I didn't see any changes). The bitmap config is provided when creating the original bitmap

navaronbracke · 2025-02-17T22:01:42Z

example/pubspec.yaml

@@ -19,7 +19,7 @@ dependencies:
  flutter:
    sdk: flutter

-  image_picker: ^1.0.4


Bumping image picker (and updating the pubspec.lock locally) fixed a build issue with the removal of the Android v1 embedding.

navaronbracke · 2025-02-17T22:02:50Z

android/src/main/kotlin/dev/steenbakker/mobile_scanner/MobileScannerHandler.kt

@@ -191,7 +191,7 @@ class MobileScannerHandler(
                        "textureId" to it.id,
                        "size" to mapOf("width" to it.width, "height" to it.height),
                        "naturalDeviceOrientation" to it.naturalDeviceOrientation,
-                        "isPreviewPreTransformed" to it.isPreviewPreTransformed,
+                        "handlesCropAndRotation" to it.handlesCropAndRotation,


Renamed to match the actual name from the SurfaceProducer API.

navaronbracke · 2025-02-17T22:04:17Z

example/android/.gitignore

@@ -11,3 +11,5 @@ GeneratedPluginRegistrant.java
 key.properties
 **/*.keystore
 **/*.jks
+
+**/.cxx


I had to add this line, since Flutter 3.29 would add a .cxx folder when compiling on Android. New flutter created templates did include a change like this, too.

navaronbracke · 2025-02-17T22:06:06Z

lib/src/method_channel/mobile_scanner_method_channel.dart

@@ -356,7 +365,6 @@ class MethodChannelMobileScanner extends MobileScannerPlatform {

    _textureId = null;
    _pausing = false;
-    _surfaceProducerDelegate?.dispose();


The disposal of the "delegate" is no longer needed, since the stream subscription is moved to a widget.

navaronbracke · 2025-02-17T22:06:25Z

lib/src/method_channel/mobile_scanner_method_channel.dart

@@ -319,9 +331,6 @@ class MethodChannelMobileScanner extends MobileScannerPlatform {
        startResult,
        cameraDirection,
      );
-      _surfaceProducerDelegate?.startListeningToDeviceOrientation(


This is now handled by a separate widget.

navaronbracke · 2025-02-17T22:12:44Z

lib/src/method_channel/rotated_preview.dart

+
+/// This widget represents a camera preview that rotates itself,
+/// based on changes in the device orientation.
+final class RotatedPreview extends StatefulWidget {


We don't use a StreamBuilder directly, due to some unknown issue with it.
The authors of the camera_android_camerax plugin had the same problem of the preview not updating correctly with the new rotation.

codecov-commenter · 2025-02-18T09:01:57Z

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (7947e61) to head (8586736).

Additional details and impacted files

@@            Coverage Diff            @@
##           develop     #1329   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           12        12           
  Lines          105       105           
=========================================
  Hits           105       105

Flag	Coverage Δ
unittests	`100.00% <ø> (ø)`

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lib/src/method_channel/rotated_preview.dart

navaronbracke added 5 commits February 13, 2025 16:57

remove device orientation stream subscription

e7e0a8a

use stream builder to observe the current orientation

e45ef54

fix compatibility with compiling for Flutter 3.29.0

47148b9

rename isPreviewPreTransformed to handlesCropAndRotation

4a710ef

adjust the surface producer delegate to use a separate preview widget…

ab036ed

… & fix formula

github-actions bot assigned navaronbracke Feb 14, 2025

remove preapplied rotation & obsolete comment

ed3a0bb

navaronbracke commented Feb 17, 2025

View reviewed changes

Merge branch 'develop' into fix_android_impeller_orientation

9ae1a30

navaronbracke commented Feb 17, 2025

View reviewed changes

Merge branch 'develop' into fix_android_impeller_orientation

1e5203a

imp: remove fixme as it is the best way to handle for now

ad1c312

juliansteenbakker approved these changes Feb 18, 2025

View reviewed changes

lib/src/method_channel/rotated_preview.dart Outdated Show resolved Hide resolved

Remove fixme comment

8586736

navaronbracke marked this pull request as ready for review February 18, 2025 15:17

juliansteenbakker merged commit 7f47cb2 into juliansteenbakker:develop Feb 18, 2025
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fix: correct android preview orientation #1329

fix: correct android preview orientation #1329

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fix: correct android preview orientation #1329

fix: correct android preview orientation #1329

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