修复4.2.1之前版本都不可以使用symbol: Function的bug

src/component/marker/MarkPointView.js

@@ -102,6 +102,10 @@ export default MarkerView.extend({
 
         mpData.each(function (idx) {
             var itemModel = mpData.getItemModel(idx);
+            var symbol = itemModel.getShallow('symbol');
+            if (typeof symbol === 'function') {
+                symbol = symbol(mpModel.getRawValue(idx), mpModel.getDataParams(idx));
+            }
             var symbolSize = itemModel.getShallow('symbolSize');
             if (typeof symbolSize === 'function') {
                 // FIXME 这里不兼容 ECharts 2.x，2.x 貌似参数是整个数据？
@@ -113,7 +117,7 @@ export default MarkerView.extend({
                 symbolSize: symbolSize,
                 color: itemModel.get('itemStyle.color')
                     || seriesData.getVisual('color'),
-                symbol: itemModel.getShallow('symbol')
+                symbol: symbol
             });
         });
 

src/util/symbol.js

@@ -332,11 +332,15 @@ function symbolPathSetColor(color, innerColor) {
 export function createSymbol(symbolType, x, y, w, h, color, keepAspect) {
     // TODO Support image object, DynamicImage.
 
+    var isFunction = typeof symbolType === 'function'
+    if (isFunction) {
+        symbolType = symbolType();
+    }
+    var symbolPath;
     var isEmpty = symbolType.indexOf('empty') === 0;
     if (isEmpty) {
         symbolType = symbolType.substr(5, 1).toLowerCase() + symbolType.substr(6);
     }
-    var symbolPath;
 
     if (symbolType.indexOf('image://') === 0) {
         symbolPath = graphic.makeImage(