title: How to position a vtkActor2D in the upper right corner?
body: <p>How can I position a <code>vtkActor2D</code> relative to the <em>upper right</em> corner of the render window? I am using the following code to load an image and display it as an overlay on my 3D scene:</p>
  
  <pre class="lang-cs prettyprint-override"><code>vtkPNGReader pngReader = vtkPNGReader.New();
  pngReader.SetFileName("image.png");
  pngReader.Update();
  
  vtkImageMapper imageMapper = vtkImageMapper.New();
  imageMapper.SetInputConnection(pngReader.GetOutputPort());
  imageMapper.SetColorWindow(255);
  imageMapper.SetColorLevel(127.5);
  
  vtkActor2D imageActor = vtkActor2D.New();
  imageActor.SetMapper(imageMapper);
  
  vtkRenderer renderer = renderWindowControl1.RenderWindow.GetRenderers().GetFirstRenderer();
  renderer.AddActor2D(imageActor);
  </code></pre>
  
  <p>I know I can set the actor's position using</p>
  
  <pre class="lang-cs prettyprint-override"><code>imageActor.SetPosition(42, 42);
  </code></pre>
  
  <p>but this is, of course, relative to the lower left corner. So how can I specify that the image is drawn relative to (respectively in) the upper right corner of the render window and stays in its relative position even during a resize of the render window? I searched the internet for several hours now but could not even find a hint.</p>