How do I add an addPolylines feature to gmaps4rails? - ruby-on-rails

Question

I'm working with the gmaps4rails gem (version 1.5.6), and I want to add the ability to add more Polylines to a map rather than replacing the Polylines that are already there. On github, this code is viewable here.
This feature already exists for Markers:
Gmaps.map.replaceMarkers(your_markers_json_array); Gmaps.map.addMarkers(your_markers_json_array);.
The Markers feature seems to be laid out in two places:
1) In gmaps4rails.base.js as:
Gmaps4Rails.prototype.addMarkers = function(new_markers) {
this.markers = this.markers.concat(new_markers);
this.create_markers();
return this.adjustMapToBounds();
};
2) In gmaps4rails.base.js.coffee as:
#add new markers to on an existing map
addMarkers : (new_markers, adjustBounds = true) ->
#update the list of markers to take into account
#markers = #markers.concat(new_markers)
#put markers on the map
#create_markers()
#adjustMapToBounds() if adjustBounds
I figured I could work with the replacePolylines code in to make my own addPolylines call:
1) In gmaps4rails.base.js near the replacePolylines code as:
Gmaps4Rails.prototype.addPolylines = function(new_polylines) {
this.polylines = this.polylines.concat(new_polylines);
this.create_polylines();
return this.adjustMapToBounds();
};
2) In gmaps4rails.base.js.coffee near the replacePolylines code as:
#add new polylines to on an existing map
addPolylines : (new_polylines) ->
#update the list of polylines to take into account
#polylines = #polylines.concat(new_polylines)
#put polylines on the map
#create_polylines()
#.... and adjust map boundaries
#adjustMapToBounds()
I've made these changes to the gem that's already added to my Rails project, and I've restarted my Rails server. I call it the same way I call replacePolylines, with Gmaps.map.addPolylines(your_polylines_json_array);. It produces an error in the console: Uncaught TypeError: Object #<Gmaps4RailsGoogle> has no method 'addPolylines'.
There doesn't seem to be anywhere else in the gmaps4rails project where I have to do anything for my addPolylines call, but I'm obviously not doing something right. Can anyone explain what I need to do to get this to work, based on this information?

Answer 1

As a workaround, until I can figure out how to build the functionality into gmaps4rails itself, I've taken these measures to asynchronously load Polylines onto a map...
In my UsersController, I've set up the show action to build a blank #polylines_json set:
def show
#user = User.find(params[:id])
#polylines_json = {}
end
The idea here is to have nothing for gmaps4rails to display on its initial map load, so that the initial page display is as quick as possible. In the view, I'm loading the map with this line:
<%= gmaps( :polylines => { :data => #polylines_json }, :map_options => { :type => 'HYBRID', :zoom => 12, :auto_adjust => false, :center_latitude => "-77", :center_longitude => "21" } ) %>
Back in the UsersController, I've got a custom action maps that is set up to handle json requests that contain from and to parameters (so that I can find items within specific ranges). It's in this action that I'm building the actual Polyline json data based on the from/to parameters:
def items
items = items.find(:all, :conditions => ['id >= ? AND id <= ?', params[:from], params[:to]])
polyline = []
i=0
items.each do |item|
polyline[i] = []
polyline[i] += [{:lng=>item.longitude.to_f,:lat=>item.latitude.to_f}]
i += 1
end
#polylines_json = polyline.to_json
respond_to do |format|
format.json { render json: #polylines_json }
end
end
Finally, back in the view to bring it all together, I'm asynchronously building up the Polyline collection ten at a time until I retrieve them all from the database:
<% content_for :scripts do %>
<script type="text/javascript" charset="utf-8">
numberOfItems = <%= #user.items.count %>;
var polylines= [];
function LoadMap(from, to) {
if (to < numberOfItems){
nextFrom = to + 1;
nextTo = to + 10;
}
if(nextTo <= numberOfItems){
$.ajax({
dataType: 'json',
url: "http://<%= request.host %>/users/<%= #user.id %>/maps.json?from="+from+"&to="+to,
success: function(response) {
polylines = polylines.concat(response);
Gmaps.map.replacePolylines(polylines);
LoadMap(nextFrom, nextTo);
}
});
}
}
LoadMap(1,10);
</script>
<% end %>