[fix] fix divide by zero exception

CHANGELOG.md

@@ -59,6 +59,8 @@
 
 ## master
 
+* (2022.09.30) 修复`Chart`在很小尺寸时出现`DivideByZeroException`异常
+
 ## v3.3.0
 
 ### 版本要点

Runtime/Component/Axis/AxisHelper.cs

@@ -261,7 +261,7 @@ namespace XCharts.Runtime
             else
             {
                 var data = axis.GetDataList(dataZoom);
-                if (axis.IsCategory() && data.Count > 0)
+                if (axis.IsCategory() && data.Count > 0 && splitNum > 0)
                 {
                     var count = axis.boundaryGap ? data.Count : data.Count - 1;
                     int tick = count / splitNum;