优化桑吉图折叠显示

Runtime/Internal/Data/GraphData.cs

@@ -42,11 +42,27 @@ namespace XCharts.Runtime
             double totalValue = 0;
             foreach (var node in nodes)
             {
-                totalValue += node.totalValues;
+                if (node.IsAnyInEdgesExpanded())
+                {
+                    totalValue += node.totalValues;
+                }
             }
             return totalValue;
         }
 
+        public static int GetExpandedNodesCount(List<GraphNode> nodes)
+        {
+            int count = 0;
+            foreach (var node in nodes)
+            {
+                if (node.IsAnyInEdgesExpanded())
+                {
+                    count++;
+                }
+            }
+            return count;
+        }
+
         public List<List<GraphNode>> GetDepthNodes()
         {
             List<List<GraphNode>> depthNodes = new List<List<GraphNode>>();