[syncfusion_flutter_charts] Zero-Line of (Step)AreaSeries does not update when changing dimensions

[DrNiels]

Bug description

I'm using AreaSeries or StepAreaSeries on a mobile device. Depending on the shown data, the Y axis shows a certain range. Now, when I change the orientation of my device, the range can change as well as the size changes. However, if the lower end of the range decreases, the lower end of the area stays at the previous lower end.

Steps to reproduce

1. Load the provided example on mobile while in portrait orientation with the Y axis starting at 94
2. Switch orientation to landscape and the Y axis now goes up to 90
3. See that the Area and StepArea series starts at 94 instead of 90
4. Also, the SplineAreaSeries works as intended!

You may need to adjust the values to ensure that the Y axis changes, depending on the device resolution. My sample works with a Samsung S24.

Code sample

Code sample

import 'package:flutter/material.dart';
import 'package:syncfusion_flutter_charts/charts.dart';

import './chart_data.dart';

void main() {
  return runApp(_ChartApp());
}

class _ChartApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(primarySwatch: Colors.blue, useMaterial3: false),
      home: _MyHomePage(),
    );
  }
}

class _MyHomePage extends StatefulWidget {
  // ignore: prefer_const_constructors_in_immutables
  _MyHomePage({Key? key}) : super(key: key);

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<_MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Syncfusion Flutter chart')),
      body: SfCartesianChart(
        primaryXAxis: DateTimeAxis(
          minimum: DateTime(2025, 11, 10),
          maximum: DateTime(2025, 11, 17),
          intervalType: DateTimeIntervalType.days,
        ),
        // Chart title
        title: ChartTitle(text: 'Half yearly sales analysis'),
        // Enable legend
        legend: Legend(isVisible: true),
        // Enable tooltip
        tooltipBehavior: TooltipBehavior(enable: true),
        series: <CartesianSeries<SalesData, DateTime>>[
          AreaSeries<SalesData, DateTime>(
            animationDuration: 0,
            dataSource: [
              SalesData(DateTime(2025, 11, 10), 100),
              SalesData(DateTime(2025, 11, 11), 112),
            ],
            xValueMapper: (SalesData sales, _) => sales.year,
            yValueMapper: (SalesData sales, _) => sales.sales,
            color: Colors.blue.withValues(alpha: 0.5),
            name: 'Area',
          ),
          SplineAreaSeries<SalesData, DateTime>(
            animationDuration: 0,
            dataSource: [
              SalesData(DateTime(2025, 11, 10), 100),
              SalesData(DateTime(2025, 11, 11), 112),
            ],
            xValueMapper: (SalesData sales, _) => sales.year,
            yValueMapper: (SalesData sales, _) => sales.sales,
            color: Colors.red.withValues(alpha: 0.5),
            name: 'Spline',
          ),
          StepAreaSeries<SalesData, DateTime>(
            animationDuration: 0,
            dataSource: [
              SalesData(DateTime(2025, 11, 10), 100),
              SalesData(DateTime(2025, 11, 11), 112),
            ],
            xValueMapper: (SalesData sales, _) => sales.year,
            yValueMapper: (SalesData sales, _) => sales.sales,
            color: Colors.green.withValues(alpha: 0.5),
            name: 'Step',
          ),
        ],
      ),
    );
  }
}

Screenshots or Video

Screenshots / Video demonstration

Starting in Portrait Mode:

Switching to Landscape: Only Spline reaches to the bottom, the other series don't

Disable Spline Series to increase visibility that the other two series do not reach the bottom

Stack Traces

Stack Traces

Not applicable

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, 3.32.0, on Microsoft Windows [Version 10.0.19045.6456], locale de-DE)
[√] Windows Version (10 Education 64-bit, 22H2, 2009)
[!] Android toolchain - develop for Android devices (Android SDK version 35.0.0)
    ! Some Android licenses not accepted. To resolve this, run: flutter doctor --android-licenses
[√] Chrome - develop for the web
[√] Visual Studio - develop Windows apps (Visual Studio Community 2022 17.14.15 (September 2025))
[!] Android Studio (version 2021.2)
    X Unable to determine bundled Java version.
[√] Android Studio (version 2024.1)
[√] VS Code, 64-bit edition (version 1.104.2)
[√] Connected device (4 available)
[√] Network resources

! Doctor found issues in 2 categories.