Change map opacity outside circle of Google Maps JavaScript API v3

Question

So I\'m currently putting a circle on my map:

    var optionsCercle = {
        center: latlang,
        map: map,
        radius: 1000,
        fillOpacity:         


        

Answer 1

Draw a circle in the opposite location and complement radius like

{-Lat, (Long-180)%180, 20037508.34-Radius}