title: Opencv: detect mouse position clicking over a picture
body: <p>I have this code in which I simply display an image using OpenCV:</p>
  
  <pre><code>    import numpy as np 
      import cv2
  
      class LoadImage:
          def loadImage(self):
              self.img=cv2.imread('photo.png')
              cv2.imshow('Test',self.img)
  
              self.pressedkey=cv2.waitKey(0)
  
              # Wait for ESC key to exit
              if self.pressedkey==27:
                  cv2.destroyAllWindows()
  
      # Start of the main program here        
      if __name__=="__main__":
          LI=LoadImage()
          LI.loadImage()
  </code></pre>
  
  <p>Once the window displayed with the photo in it, I want to display on the console (terminal) the position of the mouse when I click  over the picture. I have no idea how to perform this. Any help please?</p>