print google map

i am try to draw a line in google map,after drawing i want to print that map,but i can't print that map.

 

i am using this coding but it not print the map other contents only printed

 

function print() {
var contents = window.opener.document.getElementById("map-canvas");
document.write(contents.innerHTML);
window.print();
}

 

google.maps.event.addDomListener(window, 'load', initialize);  

in this line is load the map and draw the line,so how to print this map with markers and polylines