title: get boundaries longitude and latitude from current zoom google maps
body: <p>i need to know long and lat of my four corners of current area
  as in this image</p>
  
  <p><img src="https://i.stack.imgur.com/cqb1T.png" alt="enter image description here"></p>
  
  <p>i have tried this but with no luck :</p>
  
  <pre><code>map.getBounds();
  </code></pre>
  
  <p>any help ?</p>