Complete any pending drawing.

  DRAWNOW "flushes the event queue" and forces MATLAB to

  update the screen. 



  There are four events that cause MATLAB to flush the event

  queue and draw the screen:



  - a return to the MATLAB prompt

  - hitting a PAUSEDONZQ8 statement

  - executing a GETFRAMEGYVABD command

  - executing a DRAWNOW command



  DRAWNOW('DISCARD') causes the information to be updated as if

  the queued events were flushed, but doesn't actually flush

  them.  This is needed for printing hardcopy when the figure

  property InvertHardcopy is on.