From 5405d18044b0e5af81300915d282a8d4787fe9f6 Mon Sep 17 00:00:00 2001
From: John Firebaugh <john.firebaugh@gmail.com>
Date: Mon, 2 Dec 2013 17:01:13 -0800
Subject: [PATCH] Auto-uncheck the data and notes layers at low zoom

Reenable them when returning to high zoom in the
same session.

Fixes #592
---
 app/assets/javascripts/leaflet.layers.js | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/app/assets/javascripts/leaflet.layers.js b/app/assets/javascripts/leaflet.layers.js
index 7703529b87..5db93bd19f 100644
--- a/app/assets/javascripts/leaflet.layers.js
+++ b/app/assets/javascripts/leaflet.layers.js
@@ -132,15 +132,18 @@ L.OSM.layers = function(options) {
         var label = $('<label>')
           .appendTo(item);
 
+        var checked = map.hasLayer(layer);
+
         var input = $('<input>')
           .attr('type', 'checkbox')
-          .prop('checked', map.hasLayer(layer))
+          .prop('checked', checked)
           .appendTo(label);
 
         label.append(name);
 
         input.on('change', function() {
-          if (input.is(':checked')) {
+          checked = input.is(':checked');
+          if (checked) {
             map.addLayer(layer);
           } else {
             map.removeLayer(layer);
@@ -155,6 +158,16 @@ L.OSM.layers = function(options) {
         map.on('zoomend', function() {
           var disabled = map.getBounds().getSize() >= maxArea;
           $(input).prop('disabled', disabled);
+
+          if (disabled && $(input).is(':checked')) {
+            $(input).prop('checked', !disabled)
+              .trigger('change');
+            checked = true;
+          } else if (!disabled && !$(input).is(':checked') && checked) {
+            $(input).prop('checked', true)
+              .trigger('change');
+          }
+
           $(item).attr('class', disabled ? 'disabled' : '');
           item.attr('data-original-title', disabled ?
             I18n.t('javascripts.site.' + refName + '_zoom_in_tooltip') : '');