title: How to set the width of an AxesSubPlot?
body: <p>I have a dataset of 640 points, but plotting it in subplot <strong>scales the axis</strong> to 700. How do I set the x axis to range from 0 to 640 itself instead of scaling?</p>
  
  <p>Generally, how do I set the axes to arbitary measures? Please explain the options to set the axes.</p>
  
  <hr>
  
  <p>Here is the code I am using:</p>
  
  <pre><code>    self.figure = Figure()
      self.figure.set_size_inches( (15,3) )
      self.figure.set_dpi(80)
  
      self.picture = self.figure.add_subplot(211)
      #self.picture.xlim(xmax=640)
      self.intensity = self.figure.add_subplot(212)
  
  self.picture.imshow(pic)
  #... where projection happens to be 640 px wide
  self.intensity.plot(projection)
  </code></pre>