Simple pan method for Google map API v3 to pan the map with a certain offset. In this case, used within a custom infoWindow class.

panTo.js

CustomInfoWindow.prototype.panMap = function(marker, map) {
  var offsetX = 100
  var offsetY = 75
  var scale = Math.pow(2,map.getZoom())
  var center = map.getProjection().fromLatLngToPoint(marker.getPosition())
  var newCenterPoint = new google.maps.Point(
      center.x - offsetX/scale,
      center.y + offsetY/scale
  )
    
  var newCenter = this.map.getProjection().fromPointToLatLng(newCenterPoint)
    
  this.map.panTo(newCenter)
}