【bug】1) webmap解决dataflow图层，设置可见比例尺。轨迹线图层没有同步

       2）webmap dataflow出不来feature,样式错误。
（reviewed by chengl）

Author: Yuki-Zhao

src/openlayers/core/StyleUtils.js

@@ -702,7 +702,7 @@ export class StyleUtils {
    * @param {number} offsetY - Y方向偏移分数
    * @returns {array}
    */
-  static getIconAnchor(offsetX, offsetY) {
+  static getIconAnchor(offsetX=0.5, offsetY=0.5) {
     return [offsetX, offsetY];
   }
   /**
@@ -713,7 +713,7 @@ export class StyleUtils {
    * @param {number} offsetY - Y方向偏移分数
    * @returns {array}
    */
-  static getCircleDisplacement(radius, offsetX, offsetY) {
+  static getCircleDisplacement(radius, offsetX=0, offsetY=0) {
       const dispX = radius*offsetX, dispY = radius*offsetY;
       return [dispX, -dispY];
   }
@@ -725,7 +725,7 @@ export class StyleUtils {
    * @param {number} offsetY - Y方向偏移分数
    * @returns {object}
    */
-  static getTextOffset(fontSize, offsetX, offsetY) {
+  static getTextOffset(fontSize, offsetX=0, offsetY=0) {
     const radius = fontSize.substr(0, fontSize.length - 2) / 2;
     return {
           x: radius*offsetX, 

src/openlayers/mapping/WebMap.js

@@ -2937,11 +2937,13 @@ export class WebMap extends Observable {
             labelLayer.setZIndex(1000);
             labelSource = labelLayer.getSource();
         }
+        const {visibleScale} = layerInfo;
         if(layerInfo.lineStyle && layerInfo.visible) {
             pathLayer = this.createVectorLayer({style:layerInfo.lineStyle, featureType:"LINE"});
             pathSource = pathLayer.getSource();
             pathLayer.setZIndex(layerIndex);
             this.map.addLayer(pathLayer);
+            visibleScale && this.setVisibleScales(pathLayer, visibleScale);
         }
         let featureCache = {}, labelFeatureCache={}, pathFeatureCache = {}, that = this;
         this.createDataflowService(layerInfo, function (featureCache, labelFeatureCache, pathFeatureCache) {