title: WPF DrawingVisual on a background thread?
body: <p>I need to not block the UI while I draw lots of simple shapes using WPF.</p>
  
  <p>In WinForms, I would set up background buffer and draw to the buffer on a background thread, then draw the resulting buffer to the control. It works very well.</p>
  
  <p>In WPF, I've experimented with using a DrawingVisual, but it seems to block the UI thread while it composes the drawing.</p>
  
  <p>How would I move everything under DrawingVisual.RenderOpen() onto a background thread so that while it's working the UI thread is not blocked?</p>