don't enable canvas rendering by default. add a plugin to change the setting instead

main.js

@@ -130,7 +130,7 @@ try {
 // Disabled for now because it has several bugs: flickering, constant
 // CPU usage and it continuously fires the moveend event.
 
-L_PREFER_CANVAS = true;
+//L_PREFER_CANVAS = false;
 
 // CONFIG OPTIONS ////////////////////////////////////////////////////
 window.REFRESH = 30; // refresh view every 30s (base time)

plugins/canvas-render.user.js

@@ -0,0 +1,44 @@
+// ==UserScript==
+// @id             iitc-plugin-canvas-render@jonatkins
+// @name           IITC plugin: Use Canvas rendering
+// @category       Tweaks
+// @version        0.1.0.@@DATETIMEVERSION@@
+// @namespace      https://github.com/jonatkins/ingress-intel-total-conversion
+// @updateURL      @@UPDATEURL@@
+// @downloadURL    @@DOWNLOADURL@@
+// @description    [@@BUILDNAME@@-@@BUILDDATE@@] EXPERIMENTAL: use canvas-based rendering. Can be faster when viewing dense areas. Limited testing of the feature so far
+// @include        https://www.ingress.com/intel*
+// @include        http://www.ingress.com/intel*
+// @match          https://www.ingress.com/intel*
+// @match          http://www.ingress.com/intel*
+// @grant          none
+// ==/UserScript==
+
+@@PLUGINSTART@@
+
+// PLUGIN START ////////////////////////////////////////////////////////
+
+// we need this global variable set before leaflet initialises
+L_PREFER_CANVAS = true;
+
+// use own namespace for plugin
+window.plugin.canvasRendering = function() {};
+
+window.plugin.canvasRendering.setup  = function() {
+
+  // nothing we can do here - other than check that canvas rendering was enabled
+  if (!L.Path.CANVAS) {
+    dialog({
+      title:'Canvas Render Warning',
+      text:'The Canvas Rendering plugin failed to enable canvas rendering in leaflet. This will occur if it initialises too late.\n'
+          +'Try re-ordering userscripts so Canvas Rendering is before the main IITC script.'
+    });
+  }
+
+};
+
+var setup =  window.plugin.canvasRendering.setup;
+
+// PLUGIN END //////////////////////////////////////////////////////////
+
+@@PLUGINEND@@