增加Pie的pieType支持实心饼图和线框柄图 (#349)

Runtime/Serie/Pie/Pie.cs

@@ -2,6 +2,21 @@ using UnityEngine;
 
 namespace XCharts.Runtime
 {
+
+    public enum PieType
+    {
+        /// <summary>
+        /// solid pie chart - default fill style.
+        /// ||实心饼图 - 默认填充样式
+        /// </summary>
+        Solid,
+
+        /// <summary>
+        /// wireframe pie chart - only show the outline wireframe.
+        /// ||线框饼图 - 仅显示轮廓线框
+        /// </summary>
+        Wireframe
+    }
     [System.Serializable]
     [SerieConvert(typeof(Line), typeof(Bar))]
     [SerieHandler(typeof(PieHandler), true)]
@@ -12,10 +27,20 @@ namespace XCharts.Runtime
     public class Pie : Serie
     {
         [SerializeField][Since("v3.8.1")] private bool m_RadiusGradient = false;
+        [SerializeField][Since("v3.15.0")] private PieType m_PieType = PieType.Solid;
 
         public override SerieColorBy defaultColorBy { get { return SerieColorBy.Data; } }
         public override bool titleJustForSerie { get { return true; } }
 
+        /// <summary>
+        /// Pie chart type.
+        /// || 饼图类型。
+        /// </summary>
+        public PieType pieType
+        {
+            get { return m_PieType; }
+            set { if (PropertyUtil.SetStruct(ref m_PieType, value)) { SetVerticesDirty(); } }
+        }
         /// <summary>
         /// Whether to use gradient color in pie chart.
         /// || 是否开启半径方向的渐变效果。