Capture UI elements Windows

CaptureUiElements.cs

protected async Task<RenderTargetBitmap> CaptureUiElementToStreamAsync(FrameworkElement uiElement,
    IRandomAccessStream stream)
{
    return await CaptureUiElementToStreamAsync(uiElement, stream, BitmapEncoder.PngEncoderId);
}

private async Task<RenderTargetBitmap> CaptureUiElementToStreamAsync(FrameworkElement uiElement,
    IRandomAccessStream stream, Guid encoderId)
{
    if (uiElement == null) throw new ArgumentNullException(nameof(uiElement));
    if (stream == null) throw new ArgumentNullException(nameof(stream));
    if (BitmapEncoder.GetEncoderInformationEnumerator().All(id => id.CodecId != encoderId))
        throw new ArgumentException("Unknown encoder id", nameof(encoderId));

    try
    {
        var renderTagetBitmap = new RenderTargetBitmap();
        await renderTagetBitmap.RenderAsync(uiElement);

        var pixels = await renderTagetBitmap.GetPixelsAsync();
        var logicalDpi = DisplayInformation.GetForCurrentView().LogicalDpi;
        var encoder = await BitmapEncoder.CreateAsync(encoderId, stream);
        encoder.SetPixelData(BitmapPixelFormat.Bgra8,
            BitmapAlphaMode.Ignore,
            (uint) renderTagetBitmap.PixelWidth,
            (uint) renderTagetBitmap.PixelHeight,
            logicalDpi,
            logicalDpi,
            pixels.ToArray());

        await encoder.FlushAsync();

        return renderTagetBitmap;
    }
    catch (Exception e)
    {
        Mvx.TaggedTrace("BaseView:CaptureUiElementToStreamAsync()", "Failed with exception:\n{0}", e);
    }

    return null;
}