private static void TakeScreenshot(Camera camera, int width, int height, string outputFilePath)
    {
        RenderTexture renderTexture = new RenderTexture(width, height, 0, RenderTextureFormat.ARGB32, RenderTextureReadWrite.Linear);
        renderTexture.Create();
        if (!renderTexture.IsCreated())
        {
            throw new Exception("Failed to create render texture");
        }

        // render
        RenderTexture savedTexture = camera.targetTexture;
        camera.targetTexture = renderTexture;
        camera.Render();
        camera.targetTexture = savedTexture;

        // copy to Texture2D
        RenderTexture savedRenderTexture = RenderTexture.active;
        RenderTexture.active = renderTexture;
        Texture2D screenshot = new Texture2D(width, height, TextureFormat.ARGB32, mipmap: false);
        screenshot.ReadPixels(new Rect(0, 0, width, height), 0, 0);
        screenshot.Apply();
        RenderTexture.active = savedRenderTexture;

        // write to file
        byte[] bytes = screenshot.EncodeToPNG();
        System.IO.File.WriteAllBytes(outputFilePath, bytes);
        Debug.Log("Saved screenshot to " + outputFilePath);
    }

<UserControl ...>
    <Grid x:Name="LayoutRoot">
        <Viewbox>
		    <Grid Width="900" Height="600" Margin="50">
				<TextBlock Text="XAML Text" FontSize="72" />
		    </Grid>
	    </Viewbox>
    </Grid>
  </UserControl>

    View.RenderFlags? _renderFlagsOverride = null;
    public void OverrideRenderFlags(View.RenderFlags? newRenderFlags)
    {
        _renderFlagsOverride = newRenderFlags;
        LateUpdate();
    }

    private void UpdateSettings()
...

        if (_renderFlagsOverride.HasValue)
        {
            _uiView.SetFlags(_renderFlagsOverride.Value);
        }
        else
        {
            _uiView.SetFlags(renderFlags);
        }

/// <summary>
/// Add ability to take screenshots with Noesis by pressing ` key
/// </summary>
public class ScreenGrabber : MonoBehaviour
{
    Camera _camera;
    NoesisView _noesisView;
    public string OutputPng = @"D:\@Niko\Projects\Fantasia\Assets\TestScreenshots\test.png";
    public int Width = 4096;
    public int Height = 3072;

    // Use this for initialization
    void Start()
    {
        _camera = GetComponent<Camera>();
        _noesisView = GetComponent<NoesisView>();
    }

    int _framesToScreenshot = -1;
    bool _savedEnablePostProcess;

    // Update is called once per frame
    void Update()
    {
        if (Input.GetKeyDown(KeyCode.BackQuote)) // if "`"
        {
            _framesToScreenshot = 1;
            _savedEnablePostProcess = _noesisView.EnablePostProcess;
            _noesisView.EnablePostProcess = true;
            _noesisView.OverrideRenderFlags(Noesis.View.RenderFlags.FlipY);
        }

        if (_framesToScreenshot >= 0)
        {
            _framesToScreenshot--;
        }

        if (_framesToScreenshot == 0)
        {
            TakeScreenshot(_camera, _noesisView, Width, Height, OutputPng);
            Application.OpenURL(OutputPng);

            _noesisView.EnablePostProcess = _savedEnablePostProcess;
            _noesisView.OverrideRenderFlags(null);
        }
    }

    private static RenderTexture CreateRenderTexture(int width, int height, RenderTextureFormat format = RenderTextureFormat.ARGB32)
    {
        RenderTexture result = new RenderTexture(width, height, 0, format, RenderTextureReadWrite.Linear);
        result.useMipMap = false;
        result.antiAliasing = 1;
        result.Create();
        if (!result.IsCreated())
        {
            throw new Exception("NOOO!!");
        }
        return result;
    }

    private static void TakeScreenshot(Camera camera, NoesisView noesis, int width, int height, string outputFilePath)
    {
        // create a clone of noesis to render to a temp texture
        //GameObject noesisObject = new GameObject("NoesisOnly");

        //Camera noesisCamera = noesisObject.AddComponent<Camera>();
        //noesisCamera.clearFlags = CameraClearFlags.SolidColor;
        //noesisCamera.backgroundColor = new UnityEngine.Color(0.0f, 0.0f, 0.0f, 0.0f);
        //noesisCamera.renderingPath = RenderingPath.Forward;
        //noesisCamera.depthTextureMode = DepthTextureMode.None;
        //noesisCamera.opaqueSortMode = UnityEngine.Rendering.OpaqueSortMode.NoDistanceSort;
        //noesisCamera.transparencySortMode = TransparencySortMode.Orthographic;
        //noesisCamera.clearStencilAfterLightingPass = false;
        //noesisCamera.hdr = false;
        //noesisCamera.useOcclusionCulling = false;
        //noesisCamera.cullingMask = 0;
        //noesisCamera.targetTexture = CreateRenderTexture(width, height);


        //NoesisView noesisClone = noesisObject.AddComponent<NoesisView>();
        ////noesisClone.Xaml = noesis.Xaml;

        //noesisClone.Xaml = (NoesisXaml)UnityEngine.Resources.Load("ScoreWindow1");
        //Debug.Log(noesisClone.Xaml);
        //noesisClone.LoadXaml(true); // CRASH!!!
        //noesisClone.EnablePostProcess = true;
        //noesisClone.AntiAliasingMode = Noesis.View.AntialiasingMode.MSAA;
        //noesisClone.TessellationQuality = Noesis.View.TessellationQuality.High;
        //noesisClone.RenderFlags = Noesis.View.RenderFlags.FlipY
        //noesisCamera.Render(); // CRASH!!!

        // render to texture
        RenderTexture sceneNoNoesisTexture = CreateRenderTexture(width, height);
        RenderTexture savedTexture = camera.targetTexture;
        camera.targetTexture = sceneNoNoesisTexture;
        camera.Render();
        camera.targetTexture = savedTexture;

        // copy to Texture2D
        RenderTexture savedRenderTexture = RenderTexture.active;
        RenderTexture.active = sceneNoNoesisTexture;
        Texture2D screenshot = new Texture2D(width, height, TextureFormat.ARGB32, mipmap: false);
        screenshot.ReadPixels(new Rect(0, 0, width, height), 0, 0);
        screenshot.Apply();
        RenderTexture.active = savedRenderTexture;

        // write to file
        byte[] bytes = screenshot.EncodeToPNG();
        System.IO.File.WriteAllBytes(outputFilePath, bytes);
        Debug.Log("Saved screenshot to " + outputFilePath);
    }

}