function GPointFG(map, gmarker) 
{
	this.gmarker = gmarker
	this.gpoint
	this.map = map
}

function subGPoints(a,b) { 
  return new GPoint(a.x-b.x, a.y-b.y); 
}  

GPointFG.prototype.updateXY = function()
{
  this.zoom = this.map.getZoom()
  
  var TlcLatLng = this.map.fromContainerPixelToLatLng(new GPoint(0,0),true); 
  var TlcDivPixel = this.map.fromLatLngToDivPixel(TlcLatLng); 
  var pointDivPixel = this.map.fromLatLngToDivPixel(this.gmarker.getLatLng()); 
  this.gpoint = subGPoints(pointDivPixel, TlcDivPixel); 
}