wpf DocumentViewer XPS pinch to zoom and scroll using touch

iam developing a wpf app and i will enable the pinch to zoom and scrolling feature on a touchscreen.

here is my code

XAML:

and .cs

 private void myCanvas_Loaded(object sender, RoutedEventArgs e)
{
  try
  {
    string xpsFilePath = System.IO.Path.GetFullPath("XPS/" + RunViewModel._textToDisplay + ".xps");
    XpsDocument myDoc = new XpsDocument(xpsFilePath, FileAccess.Read);
    Viewer.Document = myDoc.GetFixedDocumentSequence();
    Viewer.FitToHeight();
    Viewer.FitToWidth();
    test.Height = ActualHeight;
    // Viewer.Height = ActualHeight;
    //Viewer.Width = ActualWidth;
  } catch (Exception ex)
  {
    MessageBox.Show(ex.ToString());
  }
}

private void myCanvas_SizeChanged(object sender, SizeChangedEventArgs e)
{
  Viewer.Height = (ActualHeight);
  Viewer.Width = (ActualWidth);
  Viewer.FitToHeight();
  test.Height = ActualHeight;
 // Viewer.FitToWidth();
}

i added a scrollview, but nothing happend.

What must i add?

Thanks for your help!

Solved

I now use this and everything works!

https://archive.codeplex.com/?p=multitouchtransformbehavior

easy way to use pinch to zoom rotate and scroll!