ruby on rails - Dynamically load Google Maps Markers with gmaps4rails -

how load markers inside map bounds gmaps4rails? , of course load new ones after pan and/or zoom.

directly related that, how can current boundaries , zoomlevel of map?

here how did it, replace markers after user finishes panning or zooming, if require different behavior use different event listener:

in view (index.html.erb):

<%= gmaps({ "map_options" => { "zoom" => 15,                                 "auto_adjust" => false,                                 "detect_location" => true,                                 "center_on_user" => true }}, false, true) %> 

at bottom of view add:

<script type="text/javascript" charset="utf-8">  function gmaps4rails_callback() {     google.maps.event.addlistener(gmaps4rails.map, 'idle', function () {         var bounds = gmaps4rails.map.getbounds();         drawitems(bounds);     }); }  </script> 

in application.js (using jquery):

function drawitems(thebounds) {     var url = '/venues.json/?sw_y=' + thebounds.getsouthwest().lng() +                             '&sw_x=' + thebounds.getsouthwest().lat() +                             '&ne_y=' + thebounds.getnortheast().lng() +                            '&ne_x=' + thebounds.getnortheast().lat();     $.get(url, function(newitemdata) {         gmaps4rails.replace_markers(newitemdata);     }); } 

venues_controller#index:

def index     # pull venues within visible bounds of map     if (params[:sw_y] && params[:sw_x] && params[:ne_y] && params[:ne_x])         bounds = [ [params[:sw_x].to_f, params[:sw_y].to_f],                   [params[:ne_x].to_f, params[:ne_y].to_f] ]         @venues_within_bounds = venue.within_bounds(bounds)     else         @venues_within_bounds = venue.all     end         respond_to |format|         format.html # index.html.erb         format.json {              @data = @venues_within_bounds.collect {|v| {                      :longitude => v.longitude,                       :latitude => v.latitude,                       :picture => v.marker_picture,                       :title => v.marker_title              }             render :json => @data         }     end end 

venue.rb model (using mongodb , mongoid):

def self.within_bounds(bounds)     self.where(:location.within => {"$box" => bounds }) end