增加SerieSymbol关于显示间隔的相关配置

Scripts/UI/Internal/CoordinateChart_DrawLine.cs

@@ -19,6 +19,7 @@ namespace XCharts
                 var count = serie.dataPoints.Count;
                 for (int i = 0; i < count; i++)
                 {
+                    if (!serie.symbol.ShowSymbol(i, count)) continue;
                     if (serie.lineArrow.show)
                     {
                         if (serie.lineArrow.position == LineArrow.Position.Start && i == 0) continue;

Scripts/UI/Internal/SerieSymbol.cs

@@ -82,79 +82,85 @@ namespace XCharts
         [SerializeField] private SymbolSizeCallback m_SelectedSizeCallback;
         [SerializeField] private Color m_Color;
         [SerializeField] [Range(0, 1)] private float m_Opacity = 1;
+        [SerializeField] private int m_StartIndex;
+        [SerializeField] private int m_Interval;
+        [SerializeField] private bool m_ForceShowLast = false;
 
         /// <summary>
         /// the type of symbol.
         /// 标记类型。
         /// </summary>
-        /// <value></value>
         public SerieSymbolType type { get { return m_Type; } set { m_Type = value; } }
         /// <summary>
         /// the type of symbol size.
         /// 标记图形的大小获取方式。
         /// </summary>
-        /// <value></value>
         public SerieSymbolSizeType sizeType { get { return m_SizeType; } set { m_SizeType = value; } }
         /// <summary>
         /// the size of symbol.
         /// 标记的大小。
         /// </summary>
-        /// <value></value>
         public float size { get { return m_Size; } set { m_Size = value; } }
         /// <summary>
         /// the size of selected symbol.
         /// 被选中的标记的大小。
         /// </summary>
-        /// <value></value>
         public float selectedSize { get { return m_SelectedSize; } set { m_SelectedSize = value; } }
         /// <summary>
         /// whitch data index is when the sizeType assined as FromData.
         /// 当sizeType指定为FromData时，指定的数据源索引。
         /// </summary>
-        /// <value></value>
         public int dataIndex { get { return m_DataIndex; } set { m_DataIndex = value; } }
         /// <summary>
         /// the scale of data when sizeType assined as FromData.
         /// 当sizeType指定为FromData时，指定的倍数系数。
         /// </summary>
-        /// <value></value>
         public float dataScale { get { return m_DataScale; } set { m_DataScale = value; } }
         /// <summary>
         /// the scale of selected data when sizeType assined as FromData.
         /// 当sizeType指定为FromData时，指定的高亮倍数系数。
         /// </summary>
-        /// <value></value>
         public float selectedDataScale { get { return m_SelectedDataScale; } set { m_SelectedDataScale = value; } }
         /// <summary>
         /// the callback of size when sizeType assined as Callback.
         /// 当sizeType指定为Callback时，指定的回调函数。
         /// </summary>
-        /// <value></value>
         public SymbolSizeCallback sizeCallback { get { return m_SizeCallback; } set { m_SizeCallback = value; } }
         /// <summary>
         /// the callback of size when sizeType assined as Callback.
         /// 当sizeType指定为Callback时，指定的高亮回调函数。
         /// </summary>
-        /// <value></value>
         public SymbolSizeCallback selectedSizeCallback { get { return m_SelectedSizeCallback; } set { m_SelectedSizeCallback = value; } }
         /// <summary>
         /// the color of symbol,default from serie.
         /// 标记图形的颜色，默认和系列一致。
         /// </summary>
-        /// <value></value>
         public Color color { get { return m_Color; } set { m_Color = value; } }
         /// <summary>
         /// the opacity of color.
         /// 图形标记的透明度。
         /// </summary>
-        /// <value></value>
         public float opacity { get { return m_Opacity; } set { m_Opacity = value; } }
+        /// <summary>
+        /// the index start to show symbol.
+        /// 开始显示图形标记的索引。
+        /// </summary>
+        public int startIndex { get { return m_StartIndex; } set { m_StartIndex = value; } }
+        /// <summary>
+        /// the interval of show symbol.
+        /// 显示图形标记的间隔。0表示显示所有标签，1表示隔一个隔显示一个标签，以此类推。
+        /// </summary>
+        public int interval { get { return m_Interval; } set { m_Interval = value; } }
+        /// <summary>
+        /// whether to show the last symbol.
+        /// 是否强制显示最后一个图形标记。
+        /// </summary>
+        public bool forceShowLast { get { return m_ForceShowLast; } set { m_ForceShowLast = value; } }
         private List<float> m_AnimationSize = new List<float>() { 0, 5, 10 };
         /// <summary>
         /// the setting for effect scatter.
         /// 带有涟漪特效动画的散点图的动画参数。
         /// </summary>
-        /// <value></value>
         public List<float> animationSize { get { return m_AnimationSize; } }
 
         /// <summary>
@@ -212,5 +218,14 @@ namespace XCharts
                 default: return selectedSize;
             }
         }
+
+        public bool ShowSymbol(int dataIndex, int dataCount)
+        {
+            if (type == SerieSymbolType.None) return false;
+            if (dataIndex < startIndex) return false;
+            if (m_Interval <= 0) return true;
+            if (m_ForceShowLast && dataIndex == dataCount - 1) return true;
+            return (dataIndex - startIndex) % (m_Interval + 1) == 0;
+        }
     }
 }