perf: Chart control performance improvements

maui/src/Charts/Area/Partial/CartesianChartArea.cs

@@ -1,4 +1,4 @@
-using System.Collections.ObjectModel;
+using System.Collections.ObjectModel;
 
 namespace Syncfusion.Maui.Toolkit.Charts
 {
@@ -103,8 +103,23 @@ internal void CalculateSbsPosition()
 									{
 										if (!stackingSeries.IsSbsValueCalculated && _seriesGroup != null)
 										{
-											var stackingSeriesType = stackingSeries.GetType();
-											string groupID = _seriesGroup.FirstOrDefault(x => x.Value.Any(s => s.GroupingLabel == stackingSeries.GroupingLabel && s.GetType() == stackingSeriesType)).Key;
+											string? groupID = null;
+											foreach (var group in _seriesGroup)
+											{
+												foreach (var s in group.Value)
+												{
+													if (s.GroupingLabel == stackingSeries.GroupingLabel && s.GetType() == stackingSeries.GetType())
+													{
+														groupID = group.Key;
+														break;
+													}
+												}
+
+												if (groupID != null)
+												{
+													break;
+												}
+											}
 											StackingSeriesBase stackingSeriesBase;
 											int size = SideBySideSeriesPosition.Count > 0 && groupingKeys.Count > 0 && groupingKeys.TryGetValue(groupID, out var groupValue)
 												? SideBySideSeriesPosition[groupValue].Count : 0;
@@ -354,15 +369,23 @@ internal void InvalidateMinWidth()
 
 		internal void ResetSBSSegments()
 		{
-			var sideBySideSeries = VisibleSeries?.Where(series => series.IsSideBySide).ToList();
-
-			if (sideBySideSeries != null && sideBySideSeries.Count > 0)
+			if (VisibleSeries == null)
 			{
-				SideBySideSeriesPosition = null;
+				return;
+			}
 
-				foreach (var chartSeries in sideBySideSeries)
+			bool hasSbsSeries = false;
+			foreach (var series in VisibleSeries)
+			{
+				if (series.IsSideBySide)
 				{
-					chartSeries.SegmentsCreated = false;
+					if (!hasSbsSeries)
+					{
+						SideBySideSeriesPosition = null;
+						hasSbsSeries = true;
+					}
+
+					series.SegmentsCreated = false;
 				}
 			}
 		}
@@ -407,7 +430,22 @@ static double GetSBSMaxWidth(List<CartesianSeries> seriesGroup)
 		internal void UpdateStackingSeries()
 		{
 			//if visible series count is 0 or not contain any stacking series then return.
-			if (VisibleSeries == null || VisibleSeries.Count == 0 || !VisibleSeries.Any(series => series is StackingSeriesBase && !series.SegmentsCreated))
+			if (VisibleSeries == null || VisibleSeries.Count == 0)
+			{
+				return;
+			}
+
+			bool hasStackingToCreate = false;
+			foreach (var series in VisibleSeries)
+			{
+				if (series is StackingSeriesBase && !series.SegmentsCreated)
+				{
+					hasStackingToCreate = true;
+					break;
+				}
+			}
+
+			if (!hasStackingToCreate)
 			{
 				return;
 			}

maui/src/Charts/Layouts/ChartZoomPanView.cs

@@ -115,14 +115,16 @@ void GenerateSelectionElements(ICanvas canvas, ObservableCollection<ChartAxis> a
 				{
 					if (axis.IsVertical)
 					{
-						startPoint = new Point(isOpposed ? actualArrangeRect.X : actualArrangeRect.X + actualArrangeRect.Width, selectedRect.Top);
-						endPoint = new Point(isOpposed ? actualArrangeRect.X : actualArrangeRect.X + actualArrangeRect.Width, selectedRect.Bottom);
+						double xCoord = isOpposed ? actualArrangeRect.X : actualArrangeRect.X + actualArrangeRect.Width;
+						startPoint = new Point(xCoord, selectedRect.Top);
+						endPoint = new Point(xCoord, selectedRect.Bottom);
 						tooltipPosition = isOpposed ? TooltipPosition.Right : TooltipPosition.Left;
 					}
 					else
 					{
-						startPoint = new Point(selectedRect.Left, isOpposed ? actualArrangeRect.Y + actualArrangeRect.Height : actualArrangeRect.Y);
-						endPoint = new Point(selectedRect.Right, isOpposed ? actualArrangeRect.Y + actualArrangeRect.Height : actualArrangeRect.Y);
+						double yCoord = isOpposed ? actualArrangeRect.Y + actualArrangeRect.Height : actualArrangeRect.Y;
+						startPoint = new Point(selectedRect.Left, yCoord);
+						endPoint = new Point(selectedRect.Right, yCoord);
 						tooltipPosition = isOpposed ? TooltipPosition.Top : TooltipPosition.Bottom;
 					}
 
@@ -177,7 +179,7 @@ void GenerateAxisTrackballInfos(PointF startPoint, PointF endPoint, TooltipPosit
 					ChartZoomPanView.MapChartLabelStyle(chart, axisPointInfo2.Helper, axis.TrackballLabelStyle);
 				}
 
-				Rect actualArrangeRect = new Rect(axis.ArrangeRect.X, axis.ArrangeRect.Y, axis.ArrangeRect.X + axis.ArrangeRect.Width, axis.ArrangeRect.Y + axis.ArrangeRect.Height);
+				Rect actualArrangeRect = new Rect(axisRect.X, axisRect.Y, axisRect.X + axisRect.Width, axisRect.Y + axisRect.Height);
 
 				axisPointInfo1.Helper.Show(actualArrangeRect, new Rect(startPoint.X - 1, startPoint.Y - 1, _dimension, _dimension), false);
 				axisPointInfo2.Helper.Show(actualArrangeRect, new Rect(endPoint.X - 1, endPoint.Y - 1, _dimension, _dimension), false);

maui/src/Charts/Series/CartesianSeries.cs

@@ -15,6 +15,7 @@ public abstract class CartesianSeries : ChartSeries
 		double _xAxisMax = double.MinValue;
 		double _yAxisMin = double.MaxValue;
 		double _yAxisMax = double.MinValue;
+		List<double>? _cachedIndexedXValues;
 
 		#endregion
 
@@ -1027,26 +1028,44 @@ internal override void UpdateRange()
 				return null;
 			}
 
-			double xIndexValues = 0d;
 			var xValues = ActualXValues as List<double>;
 
 			if (IsIndexed || xValues == null)
 			{
 				if (ActualXAxis is CategoryAxis categoryAxis && !categoryAxis.ArrangeByIndex || ActualXAxis == null)
 				{
-					xValues = GroupedXValuesIndexes.Count > 0 ? GroupedXValuesIndexes : (from val in (ActualXValues as List<string>) select (xIndexValues++)).ToList();
+					xValues = GroupedXValuesIndexes.Count > 0 ? GroupedXValuesIndexes : GetOrCreateIndexedXValues();
 				}
 				else
 				{
-					xValues = xValues != null ? (from val in xValues select (xIndexValues++)).ToList() : (from val in (ActualXValues as List<string>) select (xIndexValues++)).ToList();
+					xValues = GetOrCreateIndexedXValues();
 				}
 			}
 
 			return xValues;
 		}
 
+		List<double> GetOrCreateIndexedXValues()
+		{
+			int count = ActualXValues is List<double> dList ? dList.Count : (ActualXValues as List<string>)?.Count ?? 0;
+			if (_cachedIndexedXValues != null && _cachedIndexedXValues.Count == count)
+			{
+				return _cachedIndexedXValues;
+			}
+
+			var indexedValues = new List<double>(count);
+			for (int i = 0; i < count; i++)
+			{
+				indexedValues.Add(i);
+			}
+
+			_cachedIndexedXValues = indexedValues;
+			return _cachedIndexedXValues;
+		}
+
 		internal override void OnDataSourceChanged(object oldValue, object newValue)
 		{
+			_cachedIndexedXValues = null;
 			ResetAutoScroll();
 			InvalidateSideBySideSeries();
 			foreach (var item in EmptyPointIndexes)
@@ -1059,6 +1078,7 @@ internal override void OnDataSourceChanged(object oldValue, object newValue)
 
 		internal override void OnDataSource_CollectionChanged(object? sender, NotifyCollectionChangedEventArgs e)
 		{
+			_cachedIndexedXValues = null;
 			ResetAutoScroll();
 			base.OnDataSource_CollectionChanged(sender, e);
 		}

maui/src/Charts/Series/ChartSeriesPartial.cs

@@ -1411,16 +1411,19 @@ void ResetDataPoint()
 
 			if (ItemsSource != null)
 			{
-				var items = ItemsSource is IList ? ItemsSource as IList : null;
-				if (items == null)
+				bool hasData = false;
+				if (ItemsSource is IList list)
 				{
-					if (ItemsSource is IEnumerable source)
-					{
-						items = source.Cast<object>().ToList();
-					}
+					hasData = list.Count > 0;
+				}
+				else if (ItemsSource is IEnumerable source)
+				{
+					var enumerator = source.GetEnumerator();
+					hasData = enumerator.MoveNext();
+					(enumerator as IDisposable)?.Dispose();
 				}
 
-				if (items != null && items.Count > 0)
+				if (hasData)
 				{
 					GenerateDataPoints();
 				}

maui/src/Charts/Series/StackingSeriesBase.cs

@@ -330,17 +330,14 @@ void RefreshSeries()
 
 		void ResetVisibleSeries()
 		{
-			if (ChartArea != null)
+			if (ChartArea?.VisibleSeries == null)
 			{
-				var visibleSeries = ChartArea.VisibleSeries;
-				var stackingSeries = visibleSeries?.Where(series => series.IsStacking).ToList();
-
-				if (stackingSeries == null)
-				{
-					return;
-				}
+				return;
+			}
 
-				foreach (var chartSeries in stackingSeries)
+			foreach (var chartSeries in ChartArea.VisibleSeries)
+			{
+				if (chartSeries.IsStacking)
 				{
 					chartSeries.SegmentsCreated = false;
 				}