title: Google Maps check if circle area is visible within map boundaries
body: <p>I have a Google Map which contains a circle area.</p>
  <p>I want to know if the circle is currently visible within the map's boundaries.</p>
  <p>What I found so far is to check whether the <strong>center</strong> of the circle is within the boundaries, but I want to check for the whole circle and not only it's center.</p>
  <p>My code that checks if the map's current center is within the boundaries of the circle is this:</p>
  <pre><code>            google.maps.event.addListener(map, 'bounds_changed', function() 
              {                    
                  var circleBounds = circle.getBounds();
                  console.log(circleBounds.contains(map.getCenter()));
              });
  </code></pre>
  <p>So what i want is something like this, which of course is not correct:</p>
  <pre><code>circleBounds.contains(map.getBounds());
  </code></pre>