JS: load only visible (+cache) items - reload on move

1 files changed, 45 insertions, 0 deletions

diff --git a/chimere/static/chimere/js/jquery.chimere.js b/chimere/static/chimere/js/jquery.chimere.js
index e180682..2fd94a4 100644
--- a/chimere/static/chimere/js/jquery.chimere.js
+++ b/chimere/static/chimere/js/jquery.chimere.js
@@ -159,6 +159,7 @@ function transform(obj) {
             map_layers: null,
             selected_map_layer: null,
             dynamic_categories: false,
+            reload_on_move: true,
             display_submited: false,
             display_feature: null,
             display_route: null,
@@ -831,6 +832,35 @@ function transform(obj) {
                 $("#permalink a").attr("disabled", "disabled");
             }
         },
+        register_reload_on_move: function(){
+            var reload_on_move = function(evnt){
+                var map = settings.map;
+                var current_extent = ol.proj.transformExtent(
+                    map.getView().calculateExtent(map.getSize()),
+                    EPSG_PROJECTION, EPSG_DISPLAY_PROJECTION
+                );
+
+                var init;
+                if (!settings._cache_boundingbox) init = true;
+
+                if (init ||
+                    !ol.extent.containsCoordinate(settings._cache_boundingbox,
+                                                  current_extent)){
+                    // enlarge current extent to cache values
+                    x_extent = Math.abs(current_extent[2] - current_extent[0]);
+                    y_extent = Math.abs(current_extent[3] - current_extent[1]);
+                    current_extent[0] = current_extent[0] - x_extent;
+                    current_extent[1] = current_extent[1] - y_extent;
+                    current_extent[2] = current_extent[2] + x_extent;
+                    current_extent[3] = current_extent[3] + y_extent;
+                    settings._cache_boundingbox = current_extent;
+
+                    if(!init) methods.loadGeoObjects();
+                }
+            };
+            settings.map.on('moveend', reload_on_move);
+            reload_on_move();
+        },
         /* Preload icons */
         preload_images: function(){
             if (typeof extra_url == 'undefined') return;
@@ -1006,8 +1036,23 @@ function transform(obj) {
             if (!ids) ids = '0';
             var uri = extra_url + "getGeoObjects/" + ids;
             if (settings.display_submited) uri += "/A_S";
+
+            if (settings.reload_on_move && !settings._cache_boundingbox){
+                methods.register_reload_on_move();
+            }
+
+            var data = {};
+            if (settings._cache_boundingbox){
+                data = {
+                    'min_lon': settings._cache_boundingbox[0],
+                    'min_lat': settings._cache_boundingbox[1],
+                    'max_lon': settings._cache_boundingbox[2],
+                    'max_lat': settings._cache_boundingbox[3],
+                };
+            }
             $.ajax({url: uri,
                     dataType: "json",
+                    data: data,
                     success: function (data) {
                         //var start = new Date().getTime();
                         settings.dbFeatures.clear();