title: get coordinates of arrow of a line point
body: <p>Consider I have 2 points.</p>
  
  <p>QPoint(100,100)
  QPoint(200,200)</p>
  
  <p>Now, I need to draw a pointed arrow at the end of line QPoint(200,200).</p>
  
  <p>How can I get the points of the arrow coordinates since the line is in inclined angle? The arrow should be like given below.</p>
  
  <p><a href="https://i.stack.imgur.com/0l39d.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/0l39d.png" alt="enter image description here"></a></p>
  
  <p>As this is more a general question, Im tagging on pyqt5 and css.</p>