Fix RoamController not sync with model when roamDetail is manually set

src/component/helper/MapDraw.js

@@ -228,6 +228,8 @@ define(function (require) {
             var geo = mapOrGeoModel.coordinateSystem;
             var controller = this._controller;
             controller.zoomLimit = mapOrGeoModel.get('scaleLimit');
+            // Update zoom from model
+            controller.zoom = mapOrGeoModel.get('roamDetail.zoom');
             // roamType is will be set default true if it is null
             controller.enable(mapOrGeoModel.get('roam') || false);
             // FIXME mainType, subType 作为 component 的属性？

src/component/helper/RoamController.js

@@ -95,7 +95,7 @@ define(function (require) {
                 var pos = target.position;
                 var scale = target.scale;
 
-                var newZoom = this._zoom = this._zoom || 1;
+                var newZoom = this.zoom = this.zoom || 1;
                 newZoom *= zoomDelta;
                 if (zoomLimit) {
                     newZoom = Math.max(
@@ -103,8 +103,8 @@ define(function (require) {
                         zoomLimit[0]
                     );
                 }
-                var zoomScale = newZoom / this._zoom;
-                this._zoom = newZoom;
+                var zoomScale = newZoom / this.zoom;
+                this.zoom = newZoom;
                 // Keep the mouse center when scaling
                 pos[0] -= (zoomX - pos[0]) * (zoomScale - 1);
                 pos[1] -= (zoomY - pos[1]) * (zoomScale - 1);
@@ -144,6 +144,10 @@ define(function (require) {
          */
         this.zoomLimit = null;
 
+        /**
+         * @type {number}
+         */
+        this.zoom;
         /**
          * @type {module:zrender}
          */