title: CDC area size in logical units?
body: <p>I'm using function <a href="http://msdn.microsoft.com/en-us/library/8w4fzfxf.aspx" rel="nofollow">CDC::Rectangle</a> and it uses logical coordinates.
  But I want to know how large is the area on which I draw, so I can for example draw rectangle 10% of area width.</p>
  
  <p>How can I get dimensions of coordinate system from CDC?</p>