优化轴线显示箭头时的轴长绘制

Runtime/Internal/Helper/AxisHelper.cs

@@ -16,6 +16,20 @@ namespace XCharts
             return axis.axisTick.width != 0 ? axis.axisTick.width : axis.axisLine.width;
         }
 
+        /// <summary>
+        /// 包含箭头偏移的轴线长度
+        /// </summary>
+        /// <param name="axis"></param>
+        /// <returns></returns>
+        public static float GetAxisLineSymbolOffset(Axis axis)
+        {
+            if (axis.axisLine.show && axis.axisLine.symbol && axis.axisLine.symbolOffset > 0)
+            {
+                return axis.axisLine.symbolOffset;
+            }
+            return 0;
+        }
+
         /// <summary>
         /// 获得分割段数
         /// </summary>