goog地图增加菜单控件，点击google地图或者地图上的标记，菜单随之变化。

//这个构造器能获取此对象到地图盒子的绝对距离
function ContextMenu(map, options){
    var obj = {}
    this.setMap(map);
    this.map_=map;
    this.mapDiv_=map.getDiv();
    
}

ContextMenu.prototype=new google.maps.OverlayView();

ContextMenu.prototype.draw=function(){
    if(this.isVisible_){
        var mapSize=new google.maps.Size(this.mapDiv_.offsetWidth, this.mapDiv_.offsetHeight);
        var menuSize=new google.maps.Size(this.menu_.offsetWidth, this.menu_.offsetHeight);
        var mousePosition=this.getProjection().fromLatLngToDivPixel(this.position_);
        
        var left=mousePosition.x;
        var top=mousePosition.y;
        
        if(mousePosition.x>mapSize.width-menuSize.width-this.pixelOffset.x){
            left=left-menuSize.width-this.pixelOffset.x;
        } else {
            left+=this.pixelOffset.x;
        }
        
        if(mousePosition.y>mapSize.height-menuSize.height-this.pixelOffset.y){
            top=top-menuSize.height-this.pixelOffset.y;
        } else {
            top+=this.pixelOffset.y;
        }
        
        this.menu_.style.left=left+'px';
        this.menu_.style.top=top+'px';
    }
};



//新的构造器对象
var map_context_menu=new ContextMenu(map);

map.addListener('rightclick',function(e){
    var position=map_context_menu.getProjection().fromLatLngToDivPixel(e.latLng);  //得到的是点击点距离地图的绝对距离
});
marker.addListener('rightclick',function(e){
    var position=map_context_menu.getProjection().fromLatLngToDivPixel(e.latLng);
});

注，以上方法当拖动地图时，菜单的位置会出问题；； 

重新找到了方法将经纬度转为{x:111, y:222} 坐标

//将谷歌地图的经纬度转为对象像素
var fromLatLngToPixel=function(position,map){
    var scale = Math.pow(2, map.getZoom());
    var proj = map.getProjection();
    var bounds = map.getBounds();
    var nw = proj.fromLatLngToPoint(
        new google.maps.LatLng(
            bounds.getNorthEast().lat(),
            bounds.getSouthWest().lng()
        )
    );
    var point = proj.fromLatLngToPoint(position);
    return new google.maps.Point(
            Math.floor((point.x - nw.x) * scale),
            Math.floor((point.y - nw.y) * scale)
        );
    //{x: 17, y: 38}
}

//将谷歌地图的对象像素转为经纬度
var fromPixelToLatLng=function(pixel,map){
    var scale = Math.pow(2, Map.getZoom());
    var proj = Map.getProjection();
    var bounds = Map.getBounds();
    var nw = proj.fromLatLngToPoint(
        new google.maps.LatLng(
            bounds.getNorthEast().lat(),
            bounds.getSouthWest().lng()
        )
    );
    var point = new google.maps.Point();
    point.x = pixel.x / scale + nw.x;
    point.y = pixel.y / scale + nw.y;
    return proj.fromPointToLatLng(point);
}