Introduce the ability to extend camera functionality by bijington · Pull Request #3274 · CommunityToolkit/Maui

bijington · 2026-07-26T18:24:10Z

Current status

This it the remaining TODO list

Tested on macOS for both - Shared page crashes
Needs to be built and tested on Android
Needs to be built and tested on Windows

Introduce the ability to extend camera functionality for concepts such as Barcode scanning.

Replaces the original PR attempt at #2841.

Description of Change

Camera Scenarios Usage Guide

The Community Toolkit for MAUI CameraView allows extending its functionality through "Scenarios". There are two primary ways to implement a scenario: PlatformCameraScenario and FrameBasedCameraScenario.

PlatformCameraScenario

PlatformCameraScenario is designed for scenarios where you want to leverage platform-specific high-performance APIs (e.g., Google ML Kit on Android, Apple Vision framework on iOS, or Windows Media Capture APIs).

When to use it

When performance is critical.
When you want to use a feature already provided by the operating system.
When you need fine-grained control over the platform-specific camera pipeline.

Implementation Example (Windows)

In the sample project, PlatformBarcodeScanningScenario on Windows uses the MediaFrameReader to capture frames and decode them using ZXing.Net within the platform-specific code.

// Platforms/Windows/PlatformBarcodeScanningScenario.cs
public class PlatformBarcodeScanningScenario : PlatformCameraScenario
{
    // ... Windows specific implementation using MediaFrameReader
}

FrameBasedCameraScenario

FrameBasedCameraScenario is a specialized version of PlatformCameraScenario that abstracts the frame capture process. It provides a platform-agnostic OnFrameReceived method that gives you access to a CameraFrame containing raw byte data.

When to use it

When you want to share the same processing logic across all platforms.
When you have a cross-platform library (like ZXing.Net) that can process raw image data.
When you don't need the absolute maximum performance of platform-native ML frameworks.

Implementation Example (Shared)

In the sample project, SharedBarcodeScanningScenario demonstrates how to implement barcode scanning in shared code.

// SharedBarcodeScanningScenario.cs
public class SharedBarcodeScanningScenario : FrameBasedCameraScenario
{
    public override void OnFrameReceived(CameraFrame frame)
    {
        // frame.Data contains the raw byte array
        // frame.Width and frame.Height provide dimensions
        
        var luminanceSource = new RGBLuminanceSource(frame.Data, frame.Width, frame.Height);
        var result = barcodeReader.Decode(luminanceSource);

        if (result is not null)
        {
            // Handle result
        }
    }
}

Key Differences

Feature	PlatformCameraScenario	FrameBasedCameraScenario
Logic Location	Platform-specific folders	Shared code
Performance	Highest (Native APIs)	Good (Shared processing)
Complexity	Higher (Needs platform knowledge)	Lower (Abstraction handled for you)
Data Access	Native objects (e.g., `ImageProxy`, `CMSampleBuffer`)	`CameraFrame` (Raw bytes)

Usage in XAML

Both types of scenarios are used in the same way with the CameraView.

<toolkit:CameraView>
    <toolkit:CameraView.Scenarios>
        <!-- Use either a platform-specific scenario -->
        <sample:PlatformBarcodeScanningScenario Command="{Binding OnCodeDetectedCommand}" />
        
        <!-- Or a shared frame-based scenario -->
        <sample:SharedBarcodeScanningScenario Command="{Binding OnCodeDetectedCommand}" />
    </toolkit:CameraView.Scenarios>
</toolkit:CameraView>

Linked Issues

Fixes #

PR Checklist

Has a linked Issue, and the Issue has been approved(bug) or Championed (feature/proposal)
Has tests (if omitted, state reason in description)
Has samples (if omitted, state reason in description)
Rebased on top of main at time of PR
Changes adhere to coding standard
Documentation created or updated: https://github.com/MicrosoftDocs/CommunityToolkit/pulls

Additional information

Example of it working on macOS

scanning.mov

…h as Barcode scanning

CliffAgius · 2026-07-27T12:46:42Z

Are we still supporting Tizen? it's not possible to build a MAUI app on tizen as it's stuck on Net6...

Good point! I needed to patch this for the builds to pass but it won't do anything

Copilot

Pull request overview

This PR adds an extensibility mechanism to CameraView via attachable “scenarios” (e.g., barcode scanning), wires scenario handling into platform camera pipelines (Android/iOS), and provides a sample barcode-scanning page demonstrating the new capability.

Changes:

Introduces ICameraView.Scenarios / CameraView.Scenarios as a collection of CameraScenario instances.
Adds CameraManager scenario management (add/remove/reset) plus platform hooks to integrate platform-specific outputs/use-cases.
Adds a new sample page and platform implementations for barcode scanning (including an Android MLKit package reference).

Reviewed changes

Copilot reviewed 25 out of 25 changed files in this pull request and generated 15 comments.

Show a summary per file

File	Description
src/CommunityToolkit.Maui.Camera/Views/CameraView.shared.cs	Adds `Scenarios` bindable collection to `CameraView`.
src/CommunityToolkit.Maui.Camera/Interfaces/ICameraView.shared.cs	Exposes `Scenarios` on the camera view contract.
src/CommunityToolkit.Maui.Camera/Handlers/CameraViewHandler.shared.cs	Maps `Scenarios` and reacts to collection changes to update camera pipeline.
src/CommunityToolkit.Maui.Camera/Primitives/CameraScenario.shared.cs	Introduces base scenario lifecycle API (`Initialize`, attach/detach hooks).
src/CommunityToolkit.Maui.Camera/Primitives/PlatformCameraScenario.shared.cs	Adds a platform-specialized scenario base type.
src/CommunityToolkit.Maui.Camera/Primitives/PlatformCameraScenario.android.cs	Declares Android-specific platform scenario surface (`UseCase`).
src/CommunityToolkit.Maui.Camera/Primitives/PlatformCameraScenario.macios.cs	Declares Apple-specific platform scenario surface (`AVCaptureOutput`).
src/CommunityToolkit.Maui.Camera/CameraManager.shared.cs	Adds scenario list + add/remove/reset and preview refresh behavior.
src/CommunityToolkit.Maui.Camera/CameraManager.android.cs	Integrates additional `UseCase`s into rebinding flow.
src/CommunityToolkit.Maui.Camera/CameraManager.macios.cs	Integrates scenario outputs into `AVCaptureSession` startup.
src/CommunityToolkit.Maui.Camera/CameraManager.net.cs	Adds scenario APIs for unsupported platforms (throws NotSupported).
src/CommunityToolkit.Maui.Camera/CameraManager.tizen.cs	Adjusts partial method signatures and adds scenario APIs (throws NotSupported).
samples/CommunityToolkit.Maui.Sample/ViewModels/Views/ViewsGalleryViewModel.cs	Adds a sample gallery entry for barcode scanning.
samples/CommunityToolkit.Maui.Sample/ViewModels/Views/CameraView/BarcodeScanningViewModel.cs	New view model to display detected barcode text and refresh cameras.
samples/CommunityToolkit.Maui.Sample/Pages/Views/CameraView/BarcodeScanningPage.xaml	New page wiring `CameraView.Scenarios` to a barcode-scanning scenario.
samples/CommunityToolkit.Maui.Sample/Pages/Views/CameraView/BarcodeScanningPage.xaml.cs	New page code-behind to refresh camera list on appearing.
samples/CommunityToolkit.Maui.Sample/PlatformBarcodeScanningScenario.cs	Shared scenario surface (bindable `Command`) for barcode detection callbacks.
samples/CommunityToolkit.Maui.Sample/Platforms/PlatformBarcodeScanningScenario.cs	Adds a partial scenario file in Platforms folder.
samples/CommunityToolkit.Maui.Sample/Platforms/Android/PlatformBarcodeScanningScenario.cs	Android-specific scenario implementation using CameraX `ImageAnalysis`.
samples/CommunityToolkit.Maui.Sample/Platforms/Android/BarcodeAnalyzer.cs	Android barcode analyzer implementation using MLKit.
samples/CommunityToolkit.Maui.Sample/Platforms/iOS/PlatformBarcodeScanningScenario.cs	iOS-specific scenario using `AVCaptureMetadataOutput`.
samples/CommunityToolkit.Maui.Sample/Platforms/MacCatalyst/PlatformBarcodeScanningScenario.cs	Mac Catalyst-specific scenario using `AVCaptureMetadataOutput`.
samples/CommunityToolkit.Maui.Sample/MauiProgram.cs	Registers the new barcode scanning page + view model.
samples/CommunityToolkit.Maui.Sample/AppShell.xaml.cs	Adds shell mapping for barcode scanning page.
samples/CommunityToolkit.Maui.Sample/CommunityToolkit.Maui.Sample.csproj	Adds Android-only MLKit barcode scanning package reference.

+	readonly IList<CameraScenario> scenarios = [];
+
+	protected IReadOnlyList<CameraScenario> Scenarios => scenarios.AsReadOnly();


+/// <summary>
+/// 
+/// </summary>
+partial class PlatformCameraScenario : CameraScenario
+{


+/// <summary>
+/// 
+/// </summary>
+partial class PlatformCameraScenario : CameraScenario
+{


+/// <summary>
+/// 
+/// </summary>
+public partial class PlatformBarcodeScanningScenario : PlatformCameraScenario
+{
+	public ICommand? Command { get; set; }
+}


+            <toolkit:CameraView.Scenarios>
+                <sample:PlatformBarcodeScanningScenario Command="{Binding BindingContext.CodeDetectedCommand, Source={x:Reference Camera}}" />
+            </toolkit:CameraView.Scenarios>


+	/// <summary>Bindable property for <see cref="CameraScenario"/>.</summary>
+	public static readonly BindableProperty ScenariosProperty = ScenariosPropertyKey.BindableProperty;
+


 	/// <inheritdoc cref="ICameraView.StopCameraPreview"/>
-	public void StopCameraPreview() =>
-		Handler.CameraManager.StopCameraPreview();
+	public void StopCameraPreview() =>Handler.CameraManager.StopCameraPreview();



+		base.OnAppearing();
+
+		var cancellationTokenSource = new CancellationTokenSource(TimeSpan.FromSeconds(3));
+		await BindingContext.RefreshCamerasCommand.ExecuteAsync(cancellationTokenSource.Token);
+	}


+	/// <summary>
+	/// 
+	/// </summary>
+	public virtual void OnAttached()
+	{
+	}
+
+	/// <summary>
+	/// 
+	/// </summary>
+	public virtual void OnDetached()
+	{
+	}


+/// <summary>
+/// 
+/// </summary>
+public abstract partial class PlatformCameraScenario : CameraScenario
+{


…n't important

Introduce the ability to extend camera functionality for concepts suc…

559fb00

…h as Barcode scanning

bijington mentioned this pull request Jul 26, 2026

Initial attempt at platform based processing from the CameraView #2841

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CliffAgius reviewed Jul 27, 2026

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TheCodeTraveler requested a review from Copilot July 28, 2026 17:42

Copilot started reviewing on behalf of TheCodeTraveler July 28, 2026 17:42 View session

Copilot AI reviewed Jul 28, 2026

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bijington added 4 commits July 29, 2026 20:10

Fix some access modifiers and add missing xml comments

04fa058

More xml docs and sample in Windows using ZXIng for now

3d8a64a

Provide support for a shared code layer for times when performance is…

cddd00d

…n't important

Split out the sample pages

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Introduce the ability to extend camera functionality - #3274

Introduce the ability to extend camera functionality#3274
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bijington commented Jul 26, 2026 •

edited

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		readonly IList<CameraScenario> scenarios = [];

		protected IReadOnlyList<CameraScenario> Scenarios => scenarios.AsReadOnly();

		/// <summary>Bindable property for <see cref="CameraScenario"/>.</summary>
		public static readonly BindableProperty ScenariosProperty = ScenariosPropertyKey.BindableProperty;

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bijington commented Jul 26, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Current status

Description of Change

Camera Scenarios Usage Guide

PlatformCameraScenario

When to use it

Implementation Example (Windows)

FrameBasedCameraScenario

When to use it

Implementation Example (Shared)

Key Differences

Usage in XAML

Linked Issues

PR Checklist

Additional information

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bijington commented Jul 26, 2026 •

edited

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