Question

I’m writing an augmented reality app for Windows Phone 7 as a school project. I want to get the camera output and then add a layer of data over it. Is there a way to have the camera output displayed in a panel?

Answer 1

FYI: In Windows Phone SDK 7.1 (a.k.a. “Mango”) you can now write apps that use the device camera as you describe. See App Hub for a link to the latest 7.1 development tools. The documentation describes how to do this at the following link:

How to: Create a Base Camera Application for Windows Phone

But basically, add a videobrush to display the camera feed (a.k.a. the “viewfinder”). For example, here a rectangle control is used display the camera viewfinder:

    <!--Camera viewfinder >-->
    <Rectangle Width="640" Height="480" 
               HorizontalAlignment="Left" 
               x:Name="viewfinderContainer">

        <Rectangle.Fill>
            <VideoBrush x:Name="viewfinderBrush" />
        </Rectangle.Fill>
    </Rectangle>

To use the camera in the code-behind for the page, add a reference to Microsoft.XNA.Framework and put the following Using statements at top of the page:

// Directives
using Microsoft.Devices;
using System.IO;
using System.IO.IsolatedStorage;
using System.Windows.Media.Imaging;
using Microsoft.Xna.Framework.Media;

Note: you may not need all of these, I just copied it from the docs. In Visual Studio (Pro, at least), you can clean them up after you’re done by right-clicking your code file and clicking: Organize Usings | Remove Unused Usings.

Then, basically you apply the camera image to the rectangle in the OnNavigatedTo handler…

    //Code for initialization and setting the source for the viewfinder
    protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
    {

        // Initialize camera
        cam = new Microsoft.Devices.PhotoCamera();

        //Set the VideoBrush source to the camera.
        viewfinderBrush.SetSource(cam);
    }

…and dispose of the camera object in the OnNavigatingFrom.

    protected override void OnNavigatingFrom(System.Windows.Navigation.NavigatingCancelEventArgs e)
    {
        // Dispose camera to minimize power consumption and to expedite shutdown.
        cam.Dispose();

        // Good place to unhook camera event handlers too.
    }

The 7.1 docs also describe an augmented reality app in the following topic. Note that you’ll need to scroll-down to the section titled Creating a Silverlight-based Augmented Reality Application, to find the instructions for building it with Mango.

How to: Use the Combined Motion API for Windows Phone

Hope that also helps others seeking information about PhotoCamera in Windows Phone OS 7.1.

Cheers