ChartScrollEventArgs

 using cAlgo.API;
 namespace cAlgo
 {
     // This example shows how to use the Chart ChartScrollEventArgs
     [Indicator(IsOverlay = true, TimeZone = TimeZones.UTC, AccessRights = AccessRights.None)]
     public class ChartScrollEventArgsSample : Indicator
     {
         protected override void Initialize()
         {
             Chart.ScrollChanged += Chart_ScrollChanged;
         }
         private void Chart_ScrollChanged(ChartScrollEventArgs obj)
         {
             Print("Scrolled, Bars Delta : {0} | Top Y Delta: {1} | Bottom Y Delta: {2}", obj.BarsDelta, obj.TopYDelta, obj.BottomYDelta);
         }
         public override void Calculate(int index)
         {
         }
     }
 }

 import clr
 clr.AddReference("cAlgo.API")
 from cAlgo.API import *
 class Test():    
     def initialize(self):
         api.Chart.ScrollChanged += self.on_chart_scroll_changed
     def on_chart_scroll_changed(self, args):
         print(f"Scrolled, Bars Delta : {args.BarsDelta} | Top Y Delta: {args.TopYDelta} | Bottom Y Delta: {args.BottomYDelta}")