diff --git a/Bin/SunnyUI.dll b/Bin/SunnyUI.dll
index 8aa370ae..999bb33d 100644
Binary files a/Bin/SunnyUI.dll and b/Bin/SunnyUI.dll differ
diff --git a/SunnyUI/Charts/UILineChart.cs b/SunnyUI/Charts/UILineChart.cs
index 0b83d4b0..f384478c 100644
--- a/SunnyUI/Charts/UILineChart.cs
+++ b/SunnyUI/Charts/UILineChart.cs
@@ -31,7 +31,7 @@ using System.Windows.Forms;
 namespace Sunny.UI
 {
     [ToolboxItem(true)]
-    public sealed class UILineChart : UIChart
+    public class UILineChart : UIChart
     {
         private bool NeedDraw;
 
@@ -41,8 +41,8 @@ namespace Sunny.UI
             CalcData();
         }
 
-        private Point DrawOrigin;
-        private Size DrawSize;
+        protected Point DrawOrigin;
+        protected Size DrawSize;
 
         protected override void CalcData()
         {
@@ -67,8 +67,8 @@ namespace Sunny.UI
             NeedDraw = true;
         }
 
-        private UIScale XScale;
-        private UIScale YScale;
+        protected UIScale XScale;
+        protected UIScale YScale;
         private double[] YLabels;
         private double[] XLabels;
 
@@ -160,6 +160,12 @@ namespace Sunny.UI
             DrawSeries(g);
             // if (BarOption.ToolTip != null && BarOption.ToolTip.AxisPointer.Type == UIAxisPointerType.Line) DrawToolTip(g);
             DrawLegend(g, Option.Legend);
+            DrawOther(g);
+        }
+
+        protected virtual void DrawOther(Graphics g)
+        {
+
         }
 
         private void DrawAxis(Graphics g)
diff --git a/SunnyUI/Charts/UIOption.cs b/SunnyUI/Charts/UIOption.cs
index 2b758d3e..0b03edb1 100644
--- a/SunnyUI/Charts/UIOption.cs
+++ b/SunnyUI/Charts/UIOption.cs
@@ -47,6 +47,8 @@ namespace Sunny.UI
         public UILeftAlignment Left { get; set; } = UILeftAlignment.Left;
 
         public float Size { get; set; } = 1.0f;
+
+        public object Tag { get; set; }
     }
 
     public class UILegend
diff --git a/SunnyUI/Charts/UIScale.cs b/SunnyUI/Charts/UIScale.cs
index 30d2e29b..73a05104 100644
--- a/SunnyUI/Charts/UIScale.cs
+++ b/SunnyUI/Charts/UIScale.cs
@@ -56,11 +56,21 @@ namespace Sunny.UI
             return origin + (float)((value - _min) * 1.0f * width / (_max - _min));
         }
 
+        public double CalcXPos(double value, int origin, int width)
+        {
+            return (float)(_min + (value - origin) * (_max - _min) * 1.0f / width);
+        }
+
         public float CalcYPixel(double value, int origin, int height)
         {
             return origin - (float)((value - _min) * 1.0f * height / (_max - _min));
         }
 
+        public double CalcYPos(double value, int origin, int height)
+        {
+            return (float)(_min + (origin - value) * (_max - _min) * 1.0f / height);
+        }
+
         public float[] CalcXPixels(double[] labels, int origin, int width)
         {
             if (labels == null) return null;