title: python: how to rotate a line 45 degrees
body: <p>I have two points and plot them as a line as below picture.</p>
  
  <pre><code>fig=plt.figure(figsize=(7,6))
  plt.plot(lont[-2:],latt[-2:],'b')
  plt.show()
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/GJaF5.png" alt="enter image description here"></p>
  
  <p>and now I want to rotated this line 45 degrees (take one of the two points as a origin)
  how should I do?</p>