Topo2: Added zoom callback to map service, to allow for adjusting map stroke-width on-the-fly.

Change-Id: I08f7bdda0b34c8e64a95a05d3c5af28fc236fe7d

web/gui/src/main/webapp/app/view/topo2/topo2.js

@@ -73,6 +73,9 @@
                 offsetY: tr[1]
             };
 
+        // Allow map service to react to change in zoom parameters
+        t2ms.zoomCallback(sc, tr);
+
         // Note: Meta data stored in the context of the current layout,
         //       automatically, by the server
 

web/gui/src/main/webapp/app/view/topo2/topo2Map.js

@@ -97,6 +97,11 @@
         zoomer.reset();
     }
 
+    function zoomCallback(sc, tr) {
+        // keep the map lines constant width while zooming
+        this.node().style('stroke-width', (2.0 / sc) + 'px');
+    }
+
     angular.module('ovTopo2')
     .factory('Topo2MapService', [
         '$log', '$location', 'Topo2ViewController', 'PrefsService',
@@ -126,7 +131,8 @@
                 setMap: setMap,
                 setUpMap: setUpMap,
                 openMapSelection: openMapSelection,
-                resetZoom: resetZoom
+                resetZoom: resetZoom,
+                zoomCallback: zoomCallback
             });
 
             return instance || new MapLayer();