title: create cartesian coordinate system c# windows forms drawing
body: <p>I created simple form and now I want to draw single objects (rectangle, circle, lines..) in relative coordinates.
  Main problem for me here is to create 2D cartesian coordinate system in middle of the form.Is it possible and how to do it??</p>
  
  <p>Main question is how to efficiently transform absolute coordinates to relative? How to create my own system so I get results in numbers (negative, positive depending on quadrant) and not in pixel?</p>
  
  <p><img src="https://i.stack.imgur.com/gduDH.png" alt="Idea">.</p>
  
  <p>Currently I made MouseMove event to display current location of mouse with <code>Cursor.Position.X</code>, <code>Cursor.Position.Y</code> and display it in label. Displayed coordinates are pixels, how to change that? I've read something about converting with <code>PointToClient</code> method but I don't really understand it.</p>
  
  <p>I am tied to windows forms becouse I already made a program in win forms and now I just want to add this feature to it.</p>
  
  <p>Thanks</p>