title: How to get a widget position inside it's layout in Kivy?
body: <p>I have a GridLayout and I added some Image widgets on it after adding of images I want to draw a rectangle in each image by using their canvas but I couldn't because I don't know the exact Image widgets positions on GridLayout.</p>
  
  <p>In last line of my Python code : <code>Rectangle(pos = (child.x - 2.4, child.y + 467), size = (70, 70))</code></p>
  
  <p>How to draw this rectangle in child(My method is not good^),</p>
  
  <p>Also Why my GridLayout not coming in center after setting it's <code>pos_hint = {"center_x" : .5}</code>?</p>