point selection index is wrong in Spline series

[amjad-haffar]

Bug description

there is a bug in onPointTap function , it get the wrong index of the point im clicking only in spline series as i tested

Steps to reproduce

when i use the line series there is function inside of it called onPointTap()
this is working perfectly , you click the point you want to select and then print(details.pointIndex)
you get the right index printed
but when you do this in SplineSeries you get wrong index its kind of shifting back with 1 index
I'm using the latest version of the package

Code sample

Code sample

SfCartesianChart(
          tooltipBehavior: tooltipBehavior,
          enableAxisAnimation: true,
          primaryYAxis: NumericAxis(
            labelFormat: '{value}',
            axisLine: AxisLine(width: 1, color: ColorManager.grey),
            majorGridLines: MajorGridLines(width: 1, color: ColorManager.grey),
            labelStyle: Utils(context).primarySmallText,
          ),
          primaryXAxis: CategoryAxis(
            rangePadding: ChartRangePadding.none,
            majorGridLines: MajorGridLines(width: 1, color: ColorManager.grey),
            axisLine: AxisLine(width: 1, color: ColorManager.grey),
          ),
          series: <CartesianSeries<dynamic, String>>[
            SplineSeries<dynamic, String>(
              splineType: SplineType.monotonic,
              onPointTap: (ChartPointDetails details) {
                setState(() {
                  if (isDaysChart) {
                    selectedIndexDays = details.pointIndex!;
                  } else {
                    selectedIndexHours = details.pointIndex!;
                  }
                });
                WidgetsBinding.instance.addPostFrameCallback((_) {
                  tooltipBehavior.showByIndex(
                    details.seriesIndex!,
                    details.pointIndex!,
                  );
                });
              },
              markerSettings:
                  MarkerSettings(isVisible: true, color: Utils(context).white),
              dataSource: filteredData,
              xValueMapper: (value, _) => value.label,
              yValueMapper: (value, _) => value.percentage,
              pointColorMapper: (d, index) {
                final isSelected = isDaysChart
                    ? selectedIndexDays == index
                    : selectedIndexHours == index;
                return isSelected
                    ? Utils(context).secondary
                    : Utils(context).primary;
              },
              dataLabelSettings: const DataLabelSettings(isVisible: false),
              animationDelay: 0.0,
              animationDuration: 2000,
            ),
          ],
        ),

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Stack Traces

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On which target platforms have you observed this bug?

Android

Flutter Doctor output

Doctor output

Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel stable, 3.29.3, on Microsoft Windows [Version 10.0.26100.2894], locale en-US)
[√] Windows Version (11 Pro 64-bit, 24H2, 2009)
[√] Android toolchain - develop for Android devices (Android SDK version 35.0.0)
[√] Chrome - develop for the web
[√] Visual Studio - develop Windows apps (Visual Studio Build Tools 2019 16.11.36)
[√] Android Studio (version 2023.3)
[√] VS Code (version 1.101.0)
[√] Connected device (4 available)
[√] Network resources

• No issues found!

[Mugunthan-Ramalingam]

Hi @amjad-haffar,

We have reviewed the shared code snippet and were able to reproduce the reported issue on our end. The fix is expected to be included in our upcoming weekly release on July 1, 2025, after the Volume 2 main release. We will notify you here once the release has been rolled out. We appreciate your patience until then.

Regards,
Mugunthan.