title: Drawline with same pen width, but the line widths are different in result
body: <p>I draw lines with the same pen, but the line widths are different in result. Why?</p>
  
  <pre><code>Bitmap b = new Bitmap(400, 400);
  Graphics g = Graphics.FromImage(b);
  g.PageUnit = GraphicsUnit.Point;
  g.Clear(Color.White);
  Pen pen = new Pen(Color.Red, 1.2f);
  
  for (int i = 20; i &lt; 200; i = i + 20)
  {
      g.DrawLine(pen, 10, i, 190, i);
  }
  
  g.Dispose();
  b.Save("d:/temp/test.png", ImageFormat.Png);
  b.Dispose()
  </code></pre>
  
  <p>Here is the result:</p>
  
  <p><img src="https://i.stack.imgur.com/dU0kx.png" alt="enter image description here"></p>