Camera API (UWP)

This document provides an in-depth guide to using the Universal Windows Platform (UWP) Camera API for capturing photos and videos. Leverage the power of Windows devices to integrate camera functionality seamlessly into your applications.

Introduction

The UWP Camera API allows developers to access and control the device's camera hardware. This enables features like taking pictures, recording videos, and previewing the camera feed within your application. We'll cover the core classes and functionalities you'll need.

Core Classes and Concepts

The primary interface for interacting with the camera in UWP is the Windows.Media.Capture.MediaCapture class. Here are some key components:

• MediaCapture: The central object for managing camera operations.
• MediaCaptureInitializationSettings: Configures how the MediaCapture object initializes, including selecting the camera, audio/video capture settings, and streaming.
• CaptureElement: A UI element that displays the camera preview.
• StorageFile: Used to save captured photos and videos to disk.

Getting Started with Camera Access

1. Requesting Camera Capabilities

Before using the camera, your application must declare the webcam capability in its package.appxmanifest file. For example:

<Capabilities>
    <Capability Name="internetClient" />
    <DeviceCapability Name="webcam" />
    <DeviceCapability Name="microphone" />
</Capabilities>

2. Initializing MediaCapture

The following C# code demonstrates how to initialize the MediaCapture object and start the preview. Ensure this code is wrapped in an asynchronous method.

using Windows.Media.Capture;
using Windows.UI.Xaml.Controls;
using System;
using System.Threading.Tasks;

public sealed partial class MainPage : Page
{
    MediaCapture mediaCapture;
    CaptureElement captureElement;

    public MainPage()
    {
        this.InitializeComponent();
        captureElement = new CaptureElement();
        // Assuming you have a Grid named 'PreviewGrid' in your XAML
        // PreviewGrid.Children.Add(captureElement);
    }

    async Task InitializeCameraAsync()
    {
        mediaCapture = new MediaCapture();
        await mediaCapture.InitializeAsync(new MediaCaptureInitializationSettings
        {
            StreamingCaptureMode = StreamingCaptureMode.VideoAndPhoto,
            PhotoCaptureSource = PhotoCaptureSource.Auto
        });

        captureElement.Source = mediaCapture;
        await mediaCapture.StartPreviewAsync();
    }

    // Call InitializeCameraAsync() when needed, e.g., in the Page_Loaded event
}

Capturing Photos

To capture a photo, you'll use the CapturePhotoToStorageFileAsync method.

using Windows.Media.MediaProperties;
using System.Threading.Tasks;
using Windows.Storage;

async Task TakePhotoAsync()
{
    if (mediaCapture == null) return;

    var photoFile = await KnownFolders.PicturesLibrary.CreateFileAsync("MyPhoto.jpg", CreationCollisionOption.GenerateUniqueName);
    await mediaCapture.CapturePhotoToStorageFileAsync(ImageEncodingProperties.Jpeg(), photoFile);
    // Photo saved to photoFile
}

Recording Videos

Video recording is handled using the MediaRecorder class or directly with MediaCapture.

using Windows.Media.MediaProperties;
using System.Threading.Tasks;
using Windows.Storage;

async Task StartRecordingAsync()
{
    if (mediaCapture == null) return;

    var videoFile = await KnownFolders.VideosLibrary.CreateFileAsync("MyVideo.mp4", CreationCollisionOption.GenerateUniqueName);
    await mediaCapture.StartRecordToStorageFileAsync(MediaEncodingProfile.CreateMp4(VideoEncodingQuality.Vga), videoFile);
    // Recording started...
}

async Task StopRecordingAsync()
{
    if (mediaCapture == null) return;
    await mediaCapture.StopRecordAsync();
    // Recording stopped and saved to videoFile
}

Error Handling

It's crucial to implement robust error handling. Common exceptions include:

• System.UnauthorizedAccessException: If the application lacks the necessary camera permissions.
• System.IO.FileNotFoundException: If the specified storage location is invalid.
• Camera-specific errors during initialization or capture.

Always wrap camera operations in try-catch blocks.

Further Resources

• Media Capture APIs
• Working with Files and Folders
• UWP Camera Sample (GitHub)