Added camera package to project

added camera plugin to project

more reverse naming

added communication bloc

layout fix

android/app/build.gradle

@@ -43,7 +43,7 @@ android {
     }
 
     defaultConfig {
-        minSdkVersion flutter.minSdkVersion
+        minSdkVersion 21
         targetSdkVersion flutter.targetSdkVersion
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName

ios/Runner.xcworkspace/contents.xcworkspacedata

@@ -4,4 +4,7 @@
    <FileRef
       location = "group:Runner.xcodeproj">
    </FileRef>
+   <FileRef
+      location = "group:Pods/Pods.xcodeproj">
+   </FileRef>
 </Workspace>

lib/data/ev_source/camera/bloc_camera.dart

@@ -0,0 +1,126 @@
+import 'dart:async';
+import 'dart:io';
+import 'dart:math';
+import 'dart:typed_data';
+import 'package:camera/camera.dart';
+import 'package:exif/exif.dart';
+import 'package:flutter/widgets.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:lightmeter/screens/metering/communication/bloc_communication_metering.dart';
+import 'package:lightmeter/screens/metering/communication/event_communication_metering.dart' as communication_event;
+import 'package:lightmeter/screens/metering/communication/state_communication_metering.dart' as communication_states;
+import 'package:lightmeter/utils/log_2.dart';
+
+import 'event_camera.dart';
+import 'state_camera.dart';
+
+class CameraBloc extends Bloc<CameraEvent, CameraState> {
+  final MeteringCommunicationBloc _communicationBloc;
+  late final StreamSubscription<communication_states.MeteringCommunicationState> _communicationSubscription;
+
+  late final _WidgetsBindingObserver _observer;
+  CameraController? _cameraController;
+  CameraController? get cameraController => _cameraController;
+
+  CameraBloc(this._communicationBloc) : super(const CameraInitState()) {
+    _communicationSubscription = _communicationBloc.stream.listen(_onCommunicationState);
+
+    _observer = _WidgetsBindingObserver(_appLifecycleStateObserver);
+    WidgetsBinding.instance.addObserver(_observer);
+
+    on<InitializeEvent>(_onInitialized);
+
+    add(const InitializeEvent());
+  }
+
+  @override
+  Future<void> close() async {
+    WidgetsBinding.instance.removeObserver(_observer);
+    _cameraController?.dispose();
+    await _communicationSubscription.cancel();
+    super.close();
+  }
+
+  void _onCommunicationState(communication_states.MeteringCommunicationState communicationState) {
+    if (communicationState is communication_states.MeasureState) {
+      _takePhoto().then((ev100) {
+        if (ev100 != null) {
+          _communicationBloc.add(communication_event.MeasuredEvent(ev100));
+        }
+      });
+    }
+  }
+
+  Future<void> _onInitialized(_, Emitter emit) async {
+    emit(const CameraLoadingState());
+    try {
+      final cameras = await availableCameras();
+      _cameraController = CameraController(
+        cameras.firstWhere(
+          (camera) => camera.lensDirection == CameraLensDirection.back,
+          orElse: () => cameras.last,
+        ),
+        ResolutionPreset.medium,
+        enableAudio: false,
+      );
+
+      await _cameraController!.initialize();
+      await _cameraController!.setFlashMode(FlashMode.off);
+      emit(CameraReadyState(_cameraController!));
+    } catch (e) {
+      emit(const CameraErrorState());
+    }
+  }
+
+  Future<double?> _takePhoto() async {
+    if (_cameraController == null ||
+        !_cameraController!.value.isInitialized ||
+        _cameraController!.value.isTakingPicture) {
+      return null;
+    }
+
+    try {
+      final file = await _cameraController!.takePicture();
+      final Uint8List bytes = await file.readAsBytes();
+      Directory(file.path).deleteSync(recursive: true);
+
+      final tags = await readExifFromBytes(bytes);
+      final iso = double.parse("${tags["EXIF ISOSpeedRatings"]}");
+      final apertureValueRatio = (tags["EXIF FNumber"]!.values as IfdRatios).ratios.first;
+      final aperture = apertureValueRatio.numerator / apertureValueRatio.denominator;
+      final speedValueRatio = (tags["EXIF ExposureTime"]!.values as IfdRatios).ratios.first;
+      final speed = speedValueRatio.numerator / speedValueRatio.denominator;
+
+      return log2(pow(aperture, 2)) - log2(speed) - log2(iso / 100);
+    } on CameraException catch (e) {
+      debugPrint('Error: ${e.code}\nError Message: ${e.description}');
+      return null;
+    }
+  }
+
+  Future<void> _appLifecycleStateObserver(AppLifecycleState state) async {
+    switch (state) {
+      case AppLifecycleState.resumed:
+        add(const InitializeEvent());
+        break;
+      case AppLifecycleState.paused:
+      case AppLifecycleState.inactive:
+        _cameraController?.dispose();
+        _cameraController = null;
+        break;
+      default:
+    }
+  }
+}
+
+/// This is needed only because we cannot use `with` with mixins
+class _WidgetsBindingObserver with WidgetsBindingObserver {
+  final ValueChanged<AppLifecycleState> onLifecycleStateChanged;
+
+  _WidgetsBindingObserver(this.onLifecycleStateChanged);
+
+  @override
+  void didChangeAppLifecycleState(AppLifecycleState state) {
+    onLifecycleStateChanged(state);
+  }
+}

lib/data/ev_source/camera/event_camera.dart

@@ -0,0 +1,7 @@
+abstract class CameraEvent {
+  const CameraEvent();
+}
+
+class InitializeEvent extends CameraEvent {
+  const InitializeEvent();
+}

lib/data/ev_source/camera/state_camera.dart

@@ -0,0 +1,23 @@
+import 'package:camera/camera.dart';
+
+abstract class CameraState {
+  const CameraState();
+}
+
+class CameraInitState extends CameraState {
+  const CameraInitState();
+}
+
+class CameraLoadingState extends CameraState {
+  const CameraLoadingState();
+}
+
+class CameraReadyState extends CameraState {
+  final CameraController controller;
+
+  const CameraReadyState(this.controller);
+}
+
+class CameraErrorState extends CameraState {
+  const CameraErrorState();
+}

lib/main.dart

@@ -1,16 +1,13 @@
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
-import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:flutter_localizations/flutter_localizations.dart';
 import 'package:lightmeter/data/permissions_service.dart';
 import 'package:lightmeter/screens/settings/settings_screen.dart';
 import 'package:provider/provider.dart';
 
 import 'generated/l10n.dart';
-import 'models/photography_value.dart';
 import 'res/theme.dart';
-import 'screens/metering/metering_bloc.dart';
+import 'screens/metering/flow_metering.dart';
-import 'screens/metering/metering_screen.dart';
 import 'utils/stop_type_provider.dart';
 
 void main() {
@@ -45,30 +42,27 @@ class _ApplicationState extends State<Application> {
     return Provider(
       create: (context) => PermissionsService(),
       child: StopTypeProvider(
-        child: BlocProvider(
+        child: MaterialApp(
-          create: (context) => MeteringBloc(context.read<StopType>()),
+          theme: ThemeData(
-          child: MaterialApp(
+            useMaterial3: true,
-            theme: ThemeData(
+            colorScheme: lightColorScheme,
-              useMaterial3: true,
-              colorScheme: lightColorScheme,
-            ),
-            localizationsDelegates: const [
-              S.delegate,
-              GlobalMaterialLocalizations.delegate,
-              GlobalWidgetsLocalizations.delegate,
-              GlobalCupertinoLocalizations.delegate,
-            ],
-            supportedLocales: S.delegate.supportedLocales,
-            builder: (context, child) => MediaQuery(
-              data: MediaQuery.of(context).copyWith(textScaleFactor: 1.0),
-              child: child!,
-            ),
-            home: const MeteringScreen(),
-            routes: {
-              "metering": (context) => const MeteringScreen(),
-              "settings": (context) => const SettingsScreen(),
-            },
           ),
+          localizationsDelegates: const [
+            S.delegate,
+            GlobalMaterialLocalizations.delegate,
+            GlobalWidgetsLocalizations.delegate,
+            GlobalCupertinoLocalizations.delegate,
+          ],
+          supportedLocales: S.delegate.supportedLocales,
+          builder: (context, child) => MediaQuery(
+            data: MediaQuery.of(context).copyWith(textScaleFactor: 1.0),
+            child: child!,
+          ),
+          home: const MeteringFlow(),
+          routes: {
+            "metering": (context) => const MeteringFlow(),
+            "settings": (context) => const SettingsScreen(),
+          },
         ),
       ),
     );

lib/screens/metering/bloc_metering.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:math';
 
 import 'package:flutter_bloc/flutter_bloc.dart';
@@ -7,19 +8,25 @@ import 'package:lightmeter/models/iso_value.dart';
 import 'package:lightmeter/models/nd_value.dart';
 import 'package:lightmeter/models/photography_value.dart';
 import 'package:lightmeter/models/shutter_speed_value.dart';
+import 'package:lightmeter/screens/metering/communication/event_communication_metering.dart' as communication_events;
+import 'package:lightmeter/screens/metering/communication/state_communication_metering.dart' as communication_states;
 import 'package:lightmeter/utils/log_2.dart';
 
-import 'metering_event.dart';
+import 'communication/bloc_communication_metering.dart';
-import 'metering_state.dart';
+import 'event_metering.dart';
+import 'state_metering.dart';
 
 class MeteringBloc extends Bloc<MeteringEvent, MeteringState> {
+  final MeteringCommunicationBloc _communicationBloc;
+  late final StreamSubscription<communication_states.ScreenState> _communicationSubscription;
+
   List<ApertureValue> get _apertureValues => apertureValues.whereStopType(stopType);
   List<ShutterSpeedValue> get _shutterSpeedValues => shutterSpeedValues.whereStopType(stopType);
   final _random = Random();
 
   StopType stopType;
 
-  MeteringBloc(this.stopType)
+  MeteringBloc(this._communicationBloc, this.stopType)
       : super(
           MeteringState(
             iso: isoValues.where((element) => element.value == 100).first,
@@ -29,14 +36,42 @@ class MeteringBloc extends Bloc<MeteringEvent, MeteringState> {
             exposurePairs: [],
           ),
         ) {
+    _communicationSubscription = _communicationBloc.stream
+        .where((state) => state is communication_states.ScreenState)
+        .map((state) => state as communication_states.ScreenState)
+        .listen(_onCommunicationState);
+
     on<StopTypeChangedEvent>(_onStopTypeChanged);
     on<IsoChangedEvent>(_onIsoChanged);
     on<NdChangedEvent>(_onNdChanged);
-    on<MeasureEvent>(_onMeasure);
+    on<MeasureEvent>((_, __) => _communicationBloc.add(const communication_events.MeasureEvent()));
+    on<MeasuredEvent>(_onMeasured);
 
     add(const MeasureEvent());
   }
 
+  @override
+  Future<void> close() async {
+    await _communicationSubscription.cancel();
+    return super.close();
+  }
+
+  void _onCommunicationState(communication_states.ScreenState communicationState) {
+    if (communicationState is communication_states.MeasuredState) {
+      add(MeasuredEvent(communicationState.ev100));
+    }
+  }
+
+  /// https://www.scantips.com/lights/exposurecalc.html
+  Future<double> measureEv() async {
+    final aperture = _apertureValues[_random.nextInt(_apertureValues.length)];
+    final shutterSpeed = _shutterSpeedValues[_random.nextInt(_shutterSpeedValues.thirdStops().length)];
+    final iso = isoValues[_random.nextInt(isoValues.thirdStops().length)];
+
+    final evAtSystemIso = log2(pow(aperture.value, 2).toDouble() / shutterSpeed.value);
+    return evAtSystemIso - log2(iso.value / state.iso.value);
+  }
+
   void _onStopTypeChanged(StopTypeChangedEvent event, Emitter emit) {
     stopType = event.stopType;
     emit(MeteringState(
@@ -70,15 +105,8 @@ class MeteringBloc extends Bloc<MeteringEvent, MeteringState> {
     ));
   }
 
-  /// https://www.scantips.com/lights/exposurecalc.html
+  void _onMeasured(MeasuredEvent event, Emitter emit) {
-  void _onMeasure(_, Emitter emit) {
+    final ev = event.ev100 + log2(state.iso.value / 100);
-    final aperture = _apertureValues[_random.nextInt(_apertureValues.length)];
-    final shutterSpeed = _shutterSpeedValues[_random.nextInt(_shutterSpeedValues.thirdStops().length)];
-    final iso = isoValues[_random.nextInt(isoValues.thirdStops().length)];
-
-    final evAtSystemIso = log2(pow(aperture.value, 2).toDouble() / shutterSpeed.value);
-    final ev = evAtSystemIso - log2(iso.value / state.iso.value);
-
     emit(MeteringState(
       iso: state.iso,
       ev: ev,

lib/screens/metering/communication/bloc_communication_metering.dart

@@ -0,0 +1,11 @@
+import 'package:flutter_bloc/flutter_bloc.dart';
+
+import 'event_communication_metering.dart';
+import 'state_communication_metering.dart';
+
+class MeteringCommunicationBloc extends Bloc<MeteringCommunicationEvent, MeteringCommunicationState> {
+  MeteringCommunicationBloc() : super(const InitState()) {
+    on<MeasureEvent>((_, emit) => emit(const MeasureState()));
+    on<MeasuredEvent>((event, emit) => emit(MeasuredState(event.ev100)));
+  }
+}

lib/screens/metering/communication/event_communication_metering.dart

@@ -0,0 +1,21 @@
+abstract class MeteringCommunicationEvent {
+  const MeteringCommunicationEvent();
+}
+
+abstract class SourceEvent extends MeteringCommunicationEvent {
+  const SourceEvent();
+}
+
+abstract class ScreenEvent extends MeteringCommunicationEvent {
+  const ScreenEvent();
+}
+
+class MeasureEvent extends ScreenEvent {
+  const MeasureEvent();
+}
+
+class MeasuredEvent extends SourceEvent {
+  final double ev100;
+
+  const MeasuredEvent(this.ev100);
+}

lib/screens/metering/communication/state_communication_metering.dart

@@ -0,0 +1,25 @@
+abstract class MeteringCommunicationState {
+  const MeteringCommunicationState();
+}
+
+class InitState extends MeteringCommunicationState {
+  const InitState();
+}
+
+abstract class SourceState extends MeteringCommunicationState {
+  const SourceState();
+}
+
+abstract class ScreenState extends MeteringCommunicationState {
+  const ScreenState();
+}
+
+class MeasureState extends SourceState {
+  const MeasureState();
+}
+
+class MeasuredState extends ScreenState {
+  final double ev100;
+
+  const MeasuredState(this.ev100);
+}

lib/screens/metering/components/bottom_controls/components/zoom_slider.dart

@@ -0,0 +1,25 @@
+import 'package:flutter/material.dart';
+import 'package:lightmeter/res/dimens.dart';
+
+class ZoomSlider extends StatelessWidget {
+  const ZoomSlider({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Padding(
+      padding: const EdgeInsets.symmetric(horizontal: Dimens.paddingL),
+      child: Row(
+        children: [
+          const Icon(Icons.zoom_out),
+          Expanded(
+            child: Slider(
+              value: 0,
+              onChanged: (value) {},
+            ),
+          ),
+          const Icon(Icons.zoom_in),
+        ],
+      ),
+    );
+  }
+}

lib/screens/metering/components/topbar/components/camera_preview.dart

@@ -0,0 +1,57 @@
+import 'package:camera/camera.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:lightmeter/data/ev_source/camera/bloc_camera.dart';
+import 'package:lightmeter/data/ev_source/camera/state_camera.dart';
+
+class CameraView extends StatelessWidget {
+  const CameraView({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return AspectRatio(
+      aspectRatio: 3 / 4,
+      child: BlocBuilder<CameraBloc, CameraState>(
+        builder: (context, state) {
+          if (state is CameraReadyState) {
+            final value = state.controller.value;
+            return ValueListenableBuilder<CameraValue>(
+              valueListenable: state.controller,
+              builder: (_, __, ___) => AspectRatio(
+                aspectRatio:
+                    _isLandscape(value) ? value.aspectRatio : (1 / value.aspectRatio),
+                child: RotatedBox(
+                  quarterTurns: _getQuarterTurns(value),
+                  child: state.controller.buildPreview(),
+                ),
+              ),
+            );
+          }
+          return const ColoredBox(color: Colors.black);
+        },
+      ),
+    );
+  }
+
+  bool _isLandscape(CameraValue value) {
+    return <DeviceOrientation>[DeviceOrientation.landscapeLeft, DeviceOrientation.landscapeRight]
+        .contains(_getApplicableOrientation(value));
+  }
+
+  int _getQuarterTurns(CameraValue value) {
+    final Map<DeviceOrientation, int> turns = <DeviceOrientation, int>{
+      DeviceOrientation.portraitUp: 0,
+      DeviceOrientation.landscapeRight: 1,
+      DeviceOrientation.portraitDown: 2,
+      DeviceOrientation.landscapeLeft: 3,
+    };
+    return turns[_getApplicableOrientation(value)]!;
+  }
+
+  DeviceOrientation _getApplicableOrientation(CameraValue value) {
+    return value.isRecordingVideo
+        ? value.recordingOrientation!
+        : (value.previewPauseOrientation ?? value.lockedCaptureOrientation ?? value.deviceOrientation);
+  }
+}

lib/screens/metering/components/topbar/topbar.dart

@@ -6,6 +6,7 @@ import 'package:lightmeter/models/nd_value.dart';
 import 'package:lightmeter/models/photography_value.dart';
 import 'package:lightmeter/res/dimens.dart';
 
+import 'components/camera_preview.dart';
 import 'components/shared/animated_dialog.dart';
 import 'components/dialog_picker.dart';
 import 'components/reading_container.dart';
@@ -74,6 +75,13 @@ class MeteringTopBar extends StatelessWidget {
                             ),
                           ),
                           const _InnerPadding(),
+                          ReadingContainer.singleValue(
+                            value: ReadingValue(
+                              label: 'EV',
+                              value: ev.toString(),
+                            ),
+                          ),
+                          const _InnerPadding(),
                           Row(
                             children: [
                               Expanded(
@@ -111,18 +119,8 @@ class MeteringTopBar extends StatelessWidget {
                     const _InnerPadding(),
                     Expanded(
                       child: Column(
-                        crossAxisAlignment: CrossAxisAlignment.stretch,
                         children: [
-                          AnimatedDialog(
+                          const CameraView(),
-                            openedSize: Size(
-                              MediaQuery.of(context).size.width - Dimens.paddingM * 2,
-                              (MediaQuery.of(context).size.width - Dimens.paddingM * 2) / 3 * 4,
-                            ),
-                            child: const AspectRatio(
-                              aspectRatio: 3 / 4,
-                              child: ColoredBox(color: Colors.black),
-                            ),
-                          ),
                         ],
                       ),
                     ),

lib/screens/metering/event_metering.dart

@@ -27,3 +27,9 @@ class NdChangedEvent extends MeteringEvent {
 class MeasureEvent extends MeteringEvent {
   const MeasureEvent();
 }
+
+class MeasuredEvent extends MeteringEvent {
+  final double ev100;
+
+  const MeasuredEvent(this.ev100);
+}

lib/screens/metering/flow_metering.dart

@@ -0,0 +1,29 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:lightmeter/data/ev_source/camera/bloc_camera.dart';
+import 'package:lightmeter/models/photography_value.dart';
+import 'package:lightmeter/screens/metering/bloc_metering.dart';
+import 'package:lightmeter/screens/metering/communication/bloc_communication_metering.dart';
+
+import 'screen_metering.dart';
+
+class MeteringFlow extends StatelessWidget {
+  const MeteringFlow({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return MultiBlocProvider(
+      providers: [
+        BlocProvider(create: (_) => MeteringCommunicationBloc()),
+        BlocProvider(
+          create: (context) => MeteringBloc(
+            context.read<MeteringCommunicationBloc>(),
+            context.read<StopType>(),
+          ),
+        ),
+        BlocProvider(create: (context) => CameraBloc(context.read<MeteringCommunicationBloc>())),
+      ],
+      child: const MeteringScreen(),
+    );
+  }
+}

lib/screens/metering/screen_metering.dart

@@ -7,9 +7,9 @@ import 'package:lightmeter/screens/settings/settings_screen.dart';
 import 'components/bottom_controls/bottom_controls.dart';
 import 'components/exposure_pairs_list/exposure_pairs_list.dart';
 import 'components/topbar/topbar.dart';
-import 'metering_bloc.dart';
+import 'bloc_metering.dart';
-import 'metering_event.dart';
+import 'event_metering.dart';
-import 'metering_state.dart';
+import 'state_metering.dart';
 
 class MeteringScreen extends StatefulWidget {
   const MeteringScreen({super.key});

pubspec.yaml

@@ -1,12 +1,14 @@
 name: lightmeter
 description: A new Flutter project.
-publish_to: 'none'
+publish_to: "none"
 version: 1.0.0+1
 
 environment:
-  sdk: '>=2.18.0 <3.0.0'
+  sdk: ">=2.18.0 <3.0.0"
 
 dependencies:
+  camera: 0.10.0+4
+  exif: 3.1.2
   flutter:
     sdk: flutter
   flutter_bloc: ^8.1.1
@@ -61,4 +63,4 @@ flutter:
   # see https://flutter.dev/custom-fonts/#from-packages
 
 flutter_intl:
-  enabled: true
+  enabled: true