Bias autocomplete results

When autocompleting, it would be useful to bias the selection of addresses according to the current viewport:

if ($("#edit-from").is("input.form-text")) {
var input_from = document.getElementById('edit-from');
var ac_from = new google.maps.places.Autocomplete(input_from);
ac_from.bindTo('bounds', map);
google.maps.event.addListener(ac_from, 'place_changed', function() {
var place_from = ac_from.getPlace();
$("#edit-from").val(place_from.formatted_address);
showAddress();
});
}