enhance LinePointHighlighter to support callbacking the highlight points's info like position, datum and its corresponding seriers id

community_charts_common/lib/src/chart/common/behavior/line_point_highlighter.dart

@@ -36,6 +36,7 @@ import '../../layout/layout_view.dart'
         ViewMeasuredSizes;
 import '../base_chart.dart' show BaseChart, LifecycleListener;
 import '../chart_canvas.dart' show ChartCanvas, getAnimatedColor;
+import '../datum_details.dart';
 import '../processed_series.dart' show ImmutableSeries;
 import '../selection_model/selection_model.dart'
     show SelectionModel, SelectionModelType;
@@ -116,6 +117,14 @@ class LinePointHighlighter<D> implements ChartBehavior<D> {
   // data.
   final _currentKeys = <String>[];
 
+  // series ids, only highlight the data from these series
+  //
+  final List<String>? _seriesIds;
+
+  // callback the caller with the selected point
+  //
+  final  void Function(List<DatumDetails<D>>? selectedDetails)? onHighLightDatumUpdated;
+
   LinePointHighlighter(
       {SelectionModelType? selectionModelType,
       double? defaultRadiusPx,
@@ -124,6 +133,8 @@ class LinePointHighlighter<D> implements ChartBehavior<D> {
       LinePointHighlighterFollowLineType? showVerticalFollowLine,
       List<int>? dashPattern,
       bool? drawFollowLinesAcrossChart,
+      List<String>? seriesIds,
+      this.onHighLightDatumUpdated,
       SymbolRenderer? symbolRenderer})
       : selectionModelType = selectionModelType ?? SelectionModelType.info,
         defaultRadiusPx = defaultRadiusPx ?? 4.0,
@@ -134,6 +145,7 @@ class LinePointHighlighter<D> implements ChartBehavior<D> {
             LinePointHighlighterFollowLineType.nearest,
         dashPattern = dashPattern ?? [1, 3],
         drawFollowLinesAcrossChart = drawFollowLinesAcrossChart ?? true,
+        _seriesIds = seriesIds,
         symbolRenderer = symbolRenderer ?? CircleSymbolRenderer() {
     _lifecycleListener =
         LifecycleListener<D>(onAxisConfigured: _updateViewData);
@@ -181,8 +193,9 @@ class LinePointHighlighter<D> implements ChartBehavior<D> {
   void _updateViewData() {
     _currentKeys.clear();
 
-    final selectedDatumDetails =
-        _chart.getSelectedDatumDetails(selectionModelType);
+    final allSelectedDatumDetails = _chart.getSelectedDatumDetails(selectionModelType);
+    final selectedDatumDetails = allSelectedDatumDetails
+        .where((element) => _seriesIds == null || _seriesIds!.contains(element.series?.id));
 
     // Create a new map each time to ensure that we have it sorted in the
     // selection model order. This preserves the "nearestDetail" ordering, so
@@ -272,6 +285,8 @@ class LinePointHighlighter<D> implements ChartBehavior<D> {
 
     _seriesPointMap = newSeriesMap;
     _view.seriesPointMap = _seriesPointMap;
+
+    onHighLightDatumUpdated?.call(allSelectedDatumDetails);
   }
 
   @override

community_charts_common/lib/src/chart/line/line_renderer.dart

@@ -20,6 +20,7 @@ import 'package:collection/collection.dart' show IterableExtension;
 import 'package:meta/meta.dart' show visibleForTesting;
 
 import '../../common/color.dart' show Color;
+import '../../common/graphics_factory.dart';
 import '../../common/math.dart';
 import '../../data/series.dart' show AttributeKey, AccessorFn;
 import '../cartesian/axis/axis.dart'
@@ -926,6 +927,12 @@ class LineRenderer<D> extends BaseCartesianRenderer<D> {
     // creation time, since chart onInit is called after the chart is created.
     _chart = chart;
   }
+
+  @override
+  void set graphicsFactory(GraphicsFactory? graphicsFactory) {
+    super.graphicsFactory = graphicsFactory;
+    _pointRenderer.graphicsFactory = graphicsFactory;
+  }
 
   @override
   void paint(ChartCanvas canvas, double animationPercent) {

community_charts_flutter/lib/src/behaviors/line_point_highlighter.dart

@@ -20,11 +20,20 @@ import 'package:community_charts_common/community_charts_common.dart' as common
         LinePointHighlighter,
         LinePointHighlighterFollowLineType,
         SelectionModelType,
+        NullablePoint,
         SymbolRenderer;
 import 'package:meta/meta.dart' show immutable;
 
 import 'chart_behavior.dart' show ChartBehavior, GestureType;
 
+class HighlighterPointInfo<T> {
+  final common.NullablePoint? point;
+  final T? datum;
+  final String seriesId;
+
+  HighlighterPointInfo({this.point, this.datum, required this.seriesId,});
+}
+
 /// Chart behavior that monitors the specified [SelectionModel] and darkens the
 /// color for selected data.
 ///
@@ -33,7 +42,7 @@ import 'chart_behavior.dart' show ChartBehavior, GestureType;
 /// It is used in combination with SelectNearest to update the selection model
 /// and expand selection out to the domain value.
 @immutable
-class LinePointHighlighter<D> extends ChartBehavior<D> {
+class LinePointHighlighter<D, T extends Object> extends ChartBehavior<D> {
   final desiredGestures = new Set<GestureType>();
 
   final common.SelectionModelType? selectionModelType;
@@ -71,6 +80,9 @@ class LinePointHighlighter<D> extends ChartBehavior<D> {
   /// Renderer used to draw the highlighted points.
   final common.SymbolRenderer? symbolRenderer;
 
+  final List<String>? seriesIds;
+  final  void Function(List<HighlighterPointInfo<T>>? selectedDetails)? onHighLightDatumUpdated;
+
   LinePointHighlighter(
       {this.selectionModelType,
       this.defaultRadiusPx,
@@ -79,6 +91,8 @@ class LinePointHighlighter<D> extends ChartBehavior<D> {
       this.showVerticalFollowLine,
       this.dashPattern,
       this.drawFollowLinesAcrossChart,
+      this.seriesIds,
+      this.onHighLightDatumUpdated,
       this.symbolRenderer});
 
   @override
@@ -92,6 +106,8 @@ class LinePointHighlighter<D> extends ChartBehavior<D> {
         dashPattern: dashPattern,
         drawFollowLinesAcrossChart: drawFollowLinesAcrossChart,
         symbolRenderer: symbolRenderer,
+        seriesIds: seriesIds,
+        onHighLightDatumUpdated: (selectedDetails) => onHighLightDatumUpdated?.call(selectedDetails?.map((e) => HighlighterPointInfo<T>(seriesId: e.series?.id ?? '', point: e.chartPosition, datum: e.datum,)).toList()),
       );
 
   @override
@@ -108,6 +124,7 @@ class LinePointHighlighter<D> extends ChartBehavior<D> {
         showHorizontalFollowLine == o.showHorizontalFollowLine &&
         showVerticalFollowLine == o.showVerticalFollowLine &&
         selectionModelType == o.selectionModelType &&
+        seriesIds == o.seriesIds &&
         new ListEquality().equals(dashPattern, o.dashPattern) &&
         drawFollowLinesAcrossChart == o.drawFollowLinesAcrossChart;
   }
@@ -122,6 +139,7 @@ class LinePointHighlighter<D> extends ChartBehavior<D> {
       showVerticalFollowLine,
       dashPattern,
       drawFollowLinesAcrossChart,
+      seriesIds,
     );
   }
 }

community_charts_flutter/lib/src/line_chart.dart

@@ -85,6 +85,6 @@ class LineChart extends CartesianChart<num> {
   void addDefaultInteractions(List<ChartBehavior> behaviors) {
     super.addDefaultInteractions(behaviors);
 
-    behaviors.add(new LinePointHighlighter<num>());
+    behaviors.add(new LinePointHighlighter<num, Object>());
   }
 }

community_charts_flutter/lib/src/time_series_chart.dart

@@ -92,6 +92,6 @@ class TimeSeriesChart extends CartesianChart<DateTime> {
   void addDefaultInteractions(List<ChartBehavior> behaviors) {
     super.addDefaultInteractions(behaviors);
 
-    behaviors.add(new LinePointHighlighter<DateTime>());
+    behaviors.add(new LinePointHighlighter<DateTime, Object>());
   }
 }