title: Matplotlib: draw lines with width given in data coordinates
body: <p>I'm trying to figure out how to draw lines with widths in data units. For example, in the following code snippet, I would want the horizontal part of the line of width 80 to always extend from the y=-40 to the y=+40 mark, and stay that way even if the limits of the coordinate system change. Is there a way to achieve this with Line2D objects in matplotlib? Any other way to get a similar effect?</p>
  
  <pre><code>from pylab import figure, gca, Line2D
  
  figure()
  ax = gca()
  ax.set_xlim(-50, 50)
  ax.set_ylim(-75, 75)
  
  ax.add_line(Line2D([-50, 0, 50], [-50, 0, 0], linewidth=80))
  
  ax.grid()
  </code></pre>
  
  <p><img src="https://i.imgur.com/QYHArXG.png" alt="line width in screen coordinates"></p>