Windows Phone 8.1 多媒体（1）：相片

<Grid>
    <CaptureElement x:Name="capturePhotoElement"/>
</Grid>

<Page.BottomAppBar>
    <CommandBar>
        <AppBarButton x:Name="btnCapturePhoto"
                      Icon="Camera" Label="Capture"
                      Click="btnCapturePhoto_Click"/>
    </CommandBar>
</Page.BottomAppBar>

MediaCapture photoCapture;
ImageEncodingProperties imgEncodingProperties;

protected override async void OnNavigatedTo(NavigationEventArgs e)
{
    capturePhotoElement.Source = await Initialize();

    await photoCapture.StartPreviewAsync();
}

private async Task<MediaCapture> Initialize()
{
    photoCapture = new MediaCapture();
    await photoCapture.InitializeAsync();

    photoCapture.VideoDeviceController.PrimaryUse = CaptureUse.Photo;

    imgEncodingProperties = ImageEncodingProperties.CreateJpeg();
    imgEncodingProperties.Width = 640;
    imgEncodingProperties.Height = 480;

    return photoCapture;
}

private async void btnCapturePhoto_Click(object sender, RoutedEventArgs e)
{
    var photo = await KnownFolders.PicturesLibrary.CreateFileAsync("photo.jpg", CreationCollisionOption.GenerateUniqueName);

    await photoCapture.CapturePhotoToStorageFileAsync(imgEncodingProperties, photo);
}

HardwareButtons.CameraHalfPressed += HardwareButtons_CameraHalfPressed;

async void HardwareButtons_CameraHalfPressed(object sender, CameraEventArgs e)
{
    await photoCapture.VideoDeviceController.FocusControl.FocusAsync();
}

protected override void OnNavigatedFrom(NavigationEventArgs e)
{
    if( photoCapture != null )
    {
        photoCapture.Dispose();
        photoCapture = null;
    }
}

WriteableBitmap originBitmap;
WriteableBitmap editedBitmap;

private async void editButton_Click(object sender, RoutedEventArgs e)
{
    var imageSource = new BitmapImageSource(originBitmap.AsBitmap());

    using( var effect = new FilterEffect(imageSource) )
    {
        var filter = new AntiqueFilter();

        effect.Filters = new[] { filter };

        var renderer = new WriteableBitmapRenderer(effect, originBitmap);
        editedBitmap = await renderer.RenderAsync();

        editedBitmap.Invalidate();
    }

    myImage.Source = editedBitmap;
}