Introduce the ability to extend camera functionality

samples/CommunityToolkit.Maui.Sample/AppShell.xaml.cs

@@ -118,6 +118,8 @@ public partial class AppShell : Shell
 		CreateViewModelMapping<AvatarViewShadowsPage, AvatarViewShadowsViewModel, ViewsGalleryPage, ViewsGalleryViewModel>(),
 		CreateViewModelMapping<AvatarViewShapesPage, AvatarViewShapesViewModel, ViewsGalleryPage, ViewsGalleryViewModel>(),
 		CreateViewModelMapping<AvatarViewSizesPage, AvatarViewSizesViewModel, ViewsGalleryPage, ViewsGalleryViewModel>(),
+		CreateViewModelMapping<PlatformSpecificBarcodeScanningPage, PlatformSpecificBarcodeScanningViewModel, ViewsGalleryPage, ViewsGalleryViewModel>(),
+		CreateViewModelMapping<SharedBarcodeScanningPage, SharedBarcodeScanningViewModel, ViewsGalleryPage, ViewsGalleryViewModel>(),
 		CreateViewModelMapping<BasicMapsPage, BasicMapsViewModel, ViewsGalleryPage, ViewsGalleryViewModel>(),
 		CreateViewModelMapping<CameraViewPage, CameraViewViewModel, ViewsGalleryPage, ViewsGalleryViewModel>(),
 		CreateViewModelMapping<DrawingViewPage, DrawingViewViewModel, ViewsGalleryPage, ViewsGalleryViewModel>(),

samples/CommunityToolkit.Maui.Sample/CommunityToolkit.Maui.Sample.csproj

@@ -64,6 +64,12 @@
     <PackageReference Include="CommunityToolkit.Mvvm" Version="8.4.2" />
     <PackageReference Include="Microsoft.Extensions.Http.Resilience" Version="10.5.0" />
     <PackageReference Include="Microsoft.Extensions.Logging.Debug" Version="10.0.6" />
+
+    <!-- Required for 2 separate examples:
+      1. Windows implementation of the PlatformBarcodeScanningScenario, in this implementation the PackageReference is only required for Windows
+      2. Implementation of the SharedBarcodeScanningScenario. 
+    -->
+    <PackageReference Include="ZXing.Net" Version="0.16.10" />
   </ItemGroup>
 
   <PropertyGroup>
@@ -88,6 +94,11 @@
     <ProjectReference Include="..\..\src\CommunityToolkit.Maui.Maps\CommunityToolkit.Maui.Maps.csproj" />
   </ItemGroup>
 
+  <ItemGroup Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'android'">
+    <!-- Required NuGet Packages -->
+    <PackageReference Include="Xamarin.Google.MLKit.BarcodeScanning" Version="117.3.0.3" />
+  </ItemGroup>
+
   <PropertyGroup Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)'))=='windows' and $(Configuration) == 'Release'">
     <RuntimeIdentifier>win-x64</RuntimeIdentifier>
   </PropertyGroup>

samples/CommunityToolkit.Maui.Sample/MauiProgram.cs

@@ -249,6 +249,8 @@ static void RegisterViewsAndViewModels(in IServiceCollection services)
 
 		// Add Views Pages + ViewModels
 		services.AddTransientWithShellRoute<BasicMapsPage, BasicMapsViewModel>();
+		services.AddTransientWithShellRoute<PlatformSpecificBarcodeScanningPage, PlatformSpecificBarcodeScanningViewModel>();
+		services.AddTransientWithShellRoute<SharedBarcodeScanningPage, SharedBarcodeScanningViewModel>();
 		services.AddTransientWithShellRoute<CameraViewPage, CameraViewViewModel>();
 		services.AddTransientWithShellRoute<DrawingViewPage, DrawingViewViewModel>();
 		services.AddTransientWithShellRoute<ExpanderPage, ExpanderViewModel>();

samples/CommunityToolkit.Maui.Sample/Pages/Views/CameraView/PlatformSpecificBarcodeScanningPage.xaml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<pages:BasePage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+                xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+                xmlns:pages="clr-namespace:CommunityToolkit.Maui.Sample.Pages"
+                xmlns:toolkit="http://schemas.microsoft.com/dotnet/2022/maui/toolkit"
+                xmlns:viewModels="clr-namespace:CommunityToolkit.Maui.Sample.ViewModels.Views"
+                xmlns:sample="clr-namespace:CommunityToolkit.Maui.Sample"
+                Title="Platform Specific Barcode Scanning"
+                x:Class="CommunityToolkit.Maui.Sample.Pages.Views.PlatformSpecificBarcodeScanningPage"
+                x:TypeArguments="viewModels:PlatformSpecificBarcodeScanningViewModel"
+                x:DataType="viewModels:PlatformSpecificBarcodeScanningViewModel">
+
+    <Grid RowDefinitions="200,*,Auto,Auto" ColumnDefinitions="3*,*">
+        <Label Text="{Binding DetectedCode}" />
+
+        <toolkit:CameraView
+            x:Name="Camera"
+            Grid.Column="0" Grid.Row="1" Grid.ColumnSpan="2" Grid.RowSpan="3">
+            <toolkit:CameraView.Scenarios>
+                <sample:PlatformBarcodeScanningScenario Command="{Binding BindingContext.CodeDetectedCommand, Source={x:Reference Camera}}" />
+            </toolkit:CameraView.Scenarios>
+        </toolkit:CameraView>
+    </Grid>
+</pages:BasePage>

samples/CommunityToolkit.Maui.Sample/Pages/Views/CameraView/PlatformSpecificBarcodeScanningPage.xaml.cs

@@ -0,0 +1,19 @@
+using CommunityToolkit.Maui.Sample.ViewModels.Views;
+
+namespace CommunityToolkit.Maui.Sample.Pages.Views;
+
+public partial class PlatformSpecificBarcodeScanningPage : BasePage<PlatformSpecificBarcodeScanningViewModel>
+{
+	public PlatformSpecificBarcodeScanningPage(PlatformSpecificBarcodeScanningViewModel viewModel) : base(viewModel)
+	{
+		InitializeComponent();
+	}
+
+	protected override async void OnAppearing()
+	{
+		base.OnAppearing();
+
+		var cancellationTokenSource = new CancellationTokenSource(TimeSpan.FromSeconds(3));
+		await BindingContext.RefreshCamerasCommand.ExecuteAsync(cancellationTokenSource.Token);
+	}
+}

samples/CommunityToolkit.Maui.Sample/Pages/Views/CameraView/SharedBarcodeScanningPage.xaml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<pages:BasePage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+                xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+                xmlns:pages="clr-namespace:CommunityToolkit.Maui.Sample.Pages"
+                xmlns:toolkit="http://schemas.microsoft.com/dotnet/2022/maui/toolkit"
+                xmlns:viewModels="clr-namespace:CommunityToolkit.Maui.Sample.ViewModels.Views"
+                xmlns:sample="clr-namespace:CommunityToolkit.Maui.Sample"
+                Title="Shared Barcode Scanning"
+                x:Class="CommunityToolkit.Maui.Sample.Pages.Views.SharedBarcodeScanningPage"
+                x:TypeArguments="viewModels:SharedBarcodeScanningViewModel"
+                x:DataType="viewModels:SharedBarcodeScanningViewModel">
+
+    <Grid RowDefinitions="200,*,Auto,Auto" ColumnDefinitions="3*,*">
+        <Label Text="{Binding DetectedCode}" />
+
+        <toolkit:CameraView
+            x:Name="Camera"
+            Grid.Column="0" Grid.Row="1" Grid.ColumnSpan="2" Grid.RowSpan="3">
+            <toolkit:CameraView.Scenarios>
+                <sample:SharedBarcodeScanningScenario Command="{Binding BindingContext.CodeDetectedCommand, Source={x:Reference Camera}}" />
+            </toolkit:CameraView.Scenarios>
+        </toolkit:CameraView>
+    </Grid>
+</pages:BasePage>

samples/CommunityToolkit.Maui.Sample/Pages/Views/CameraView/SharedBarcodeScanningPage.xaml.cs

@@ -0,0 +1,19 @@
+using CommunityToolkit.Maui.Sample.ViewModels.Views;
+
+namespace CommunityToolkit.Maui.Sample.Pages.Views;
+
+public partial class SharedBarcodeScanningPage : BasePage<SharedBarcodeScanningViewModel>
+{
+	public SharedBarcodeScanningPage(SharedBarcodeScanningViewModel viewModel) : base(viewModel)
+	{
+		InitializeComponent();
+	}
+
+	protected override async void OnAppearing()
+	{
+		base.OnAppearing();
+
+		var cancellationTokenSource = new CancellationTokenSource(TimeSpan.FromSeconds(3));
+		await BindingContext.RefreshCamerasCommand.ExecuteAsync(cancellationTokenSource.Token);
+	}
+}

samples/CommunityToolkit.Maui.Sample/PlatformBarcodeScanningScenario.cs

@@ -0,0 +1,25 @@
+using System.Windows.Input;
+using CommunityToolkit.Maui.Core;
+
+namespace CommunityToolkit.Maui.Sample;
+
+/// <summary>
+/// A <see cref="PlatformCameraScenario"/> implementation that provides barcode scanning.
+/// </summary>
+public partial class PlatformBarcodeScanningScenario : PlatformCameraScenario
+{
+	/// <summary>
+	/// Backing BindableProperty for the <see cref="Command"/> property.
+	/// </summary>
+	public static readonly BindableProperty CommandProperty =
+		BindableProperty.Create(nameof(Command), typeof(ICommand), typeof(PlatformBarcodeScanningScenario));
+
+	/// <summary>
+	/// The Command that should be executed when a barcode is detected.
+	/// </summary>
+	public ICommand? Command
+	{
+		get => (ICommand?)GetValue(CommandProperty);
+		set => SetValue(CommandProperty, value);
+	}
+}

samples/CommunityToolkit.Maui.Sample/Platforms/Android/BarcodeAnalyzer.cs

@@ -0,0 +1,92 @@
+using System.Diagnostics;
+using System.Windows.Input;
+using Android.Gms.Tasks;
+using Android.Runtime;
+using AndroidX.Camera.Core;
+using Xamarin.Google.MLKit.Vision.Barcode.Common;
+using Xamarin.Google.MLKit.Vision.BarCode;
+using Xamarin.Google.MLKit.Vision.Common;
+
+using Scanner = Xamarin.Google.MLKit.Vision.BarCode.BarcodeScanning;
+
+namespace CommunityToolkit.Maui.Sample;
+
+public class BarcodeAnalyzer(Func<ICommand?> commandProvider) : Java.Lang.Object, ImageAnalysis.IAnalyzer
+{
+	IBarcodeScanner? barcodeScanner;
+	readonly Lock resultsLock = new();
+
+	internal void UpdateSymbologies()
+	{
+		barcodeScanner?.Dispose();
+		barcodeScanner = Scanner.GetClient(new BarcodeScannerOptions.Builder()
+			.SetBarcodeFormats(Barcode.FormatAllFormats)
+			.Build());
+	}
+
+	public void Analyze(IImageProxy proxy)
+	{
+		try
+		{
+			ArgumentNullException.ThrowIfNull(proxy?.Image);
+			ArgumentNullException.ThrowIfNull(barcodeScanner);
+
+			using var inputImage = InputImage.FromMediaImage(proxy.Image, 0);
+			using var task  = barcodeScanner.Process(inputImage);
+			var result = TasksClass.Await(task);
+
+			lock (resultsLock)
+			{
+				ProcessResults(result);
+			}
+
+			result?.Dispose();
+		}
+		catch (Exception ex)
+		{
+			Debug.WriteLine(ex);
+		}
+		finally
+		{
+			try
+			{
+				proxy?.Close();
+			}
+			catch (Exception ex)
+			{
+				Debug.WriteLine(ex);
+			}
+		}
+	}
+
+	void ProcessResults(Java.Lang.Object? result)
+	{
+		if (result is not JavaList javaList)
+		{
+			return;
+		}
+
+		if (commandProvider.Invoke() is not Command command)
+		{
+			return;
+		}
+
+		foreach (Barcode barcode in javaList)
+		{
+			if (barcode is null)
+			{
+				continue;
+			}
+
+			if (string.IsNullOrEmpty(barcode.DisplayValue) && string.IsNullOrEmpty(barcode.RawValue))
+			{
+				continue;
+			}
+
+			if (command.CanExecute(barcode.RawValue) is true)
+			{
+				command.Execute(barcode.RawValue);
+			}
+		}
+	}
+}

samples/CommunityToolkit.Maui.Sample/Platforms/Android/PlatformBarcodeScanningScenario.cs

@@ -0,0 +1,32 @@
+using AndroidX.Camera.Core;
+
+namespace CommunityToolkit.Maui.Sample;
+
+/// <summary>
+/// Android based implementation of <see cref="PlatformBarcodeScanningScenario"/>.
+/// </summary>
+public partial class PlatformBarcodeScanningScenario
+{
+	readonly Lazy<UseCase>? lazyUseCase = null;
+
+	/// <summary>
+	/// Initializes a new instance of the <see cref="PlatformBarcodeScanningScenario"/> class.
+	/// </summary>
+	public PlatformBarcodeScanningScenario()
+	{
+		lazyUseCase = new Lazy<UseCase>(() =>
+		{
+			var imageAnalysis =
+				new ImageAnalysis.Builder()
+					.SetBackpressureStrategy(ImageAnalysis.StrategyKeepOnlyLatest)
+					.Build();
+
+			imageAnalysis.SetAnalyzer(Android.Runtime.AndroidEnvironment.MainThreadExecutor, new BarcodeAnalyzer(() => Command));
+
+			return imageAnalysis;
+		});
+	}
+
+	/// <inheritdoc/>
+	public override UseCase UseCase => lazyUseCase?.Value!;
+}

samples/CommunityToolkit.Maui.Sample/Platforms/MacCatalyst/PlatformBarcodeScanningScenario.cs

@@ -0,0 +1,64 @@
+using System.Windows.Input;
+using AVFoundation;
+using CoreFoundation;
+
+namespace CommunityToolkit.Maui.Sample;
+
+/// <summary>
+/// Apple based implementation of <see cref="PlatformBarcodeScanningScenario"/>.
+/// </summary>
+public partial class PlatformBarcodeScanningScenario
+{
+	readonly Lazy<AVCaptureMetadataOutput> lazyOutput;
+
+	/// <summary>
+	/// Initializes a new instance of the <see cref="PlatformBarcodeScanningScenario"/> class.
+	/// </summary>
+	public PlatformBarcodeScanningScenario()
+	{
+		lazyOutput = new Lazy<AVCaptureMetadataOutput>(() =>
+		{
+			var output = new AVCaptureMetadataOutput();
+
+			output.SetDelegate(new BarcodeDetectionDelegate(() => Command), DispatchQueue.MainQueue);
+
+			return output;
+		});
+	}
+
+	/// <inheritdoc/>
+	public override AVCaptureOutput Output => lazyOutput.Value;
+
+	/// <inheritdoc/>
+	public override void OnAttached()
+	{
+		// Must apply this here once the output has been attached to the capture session.
+		lazyOutput.Value.MetadataObjectTypes = lazyOutput.Value.AvailableMetadataObjectTypes;
+	}
+}
+
+sealed class BarcodeDetectionDelegate(Func<ICommand?> commandProvider) : AVCaptureMetadataOutputObjectsDelegate
+{
+	public override void DidOutputMetadataObjects(
+		AVCaptureMetadataOutput captureOutput,
+		AVMetadataObject[] metadataObjects,
+		AVCaptureConnection connection)
+	{
+		foreach (var metadataObject in metadataObjects)
+		{
+			if (metadataObject is AVMetadataMachineReadableCodeObject readableObject)
+			{
+				var code = readableObject.StringValue;
+
+				Console.WriteLine($"Metadata object {code} at {string.Join(",", readableObject.Corners?? [])}");
+
+				var invokeCommand = commandProvider.Invoke(); 
+
+				if (invokeCommand?.CanExecute(readableObject.StringValue) is true)
+				{
+					invokeCommand.Execute(readableObject.StringValue);
+				}
+			}
+		}
+	}
+}

samples/CommunityToolkit.Maui.Sample/Platforms/PlatformBarcodeScanningScenario.cs

@@ -0,0 +1,12 @@
+using System.Windows.Input;
+using CommunityToolkit.Maui.Core;
+
+namespace CommunityToolkit.Maui.Sample;
+
+/// <summary>
+/// 
+/// </summary>
+public partial class PlatformBarcodeScanningScenario : PlatformCameraScenario
+{
+	public ICommand? Command { get; set; }
+}