RadarChart tick and graph point scale do not match

[ateich]

Describe the bug
RadarChart tick and graph point scale do not match

If a point has a value of 15 and a tick line has a value of 15, I would expect the point to fall on the line. This is not always the case

The values in tick titles do not always match with the values of the points on the graph because

• points are drawn assuming the graph center = 0
• tick title values assume that the graph center = (minValue - ((maxValue - minValue) / tickCount))

To Reproduce

import 'package:fl_chart/fl_chart.dart';
import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      home: Scaffold(
        body: Center(
          child: UsageRadarChart(),
        ),
      ),
    );
  }
}

class UsageRadarChart extends StatelessWidget {
  const UsageRadarChart({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      width: 300,
      height: 300,
      child:
        RadarChart(
          RadarChartData(
            tickCount: 2,
            dataSets: [
              RadarDataSet(
                dataEntries: [
                  const RadarEntry(value: 15),
                  const RadarEntry(value: 20),
                  const RadarEntry(value: 20),
                ]
              )
            ],
          ),
        ),
    );
  }
}

Screenshots

Expected	Actual
Points: [15, 20, 20]	Points: [15, 20, 20]

Versions

• which version of the Flutter are you using?

Flutter 3.0.0 • channel stable • https://github.com/flutter/flutter.git
Framework • revision ee4e09cce0 (8 weeks ago) • 2022-05-09 16:45:18 -0700
Engine • revision d1b9a6938a
Tools • Dart 2.17.0 • DevTools 2.12.2

• which version of the FlChart are you using?
  • 0.55.0 but I've been able to reproduce it as far back as 0.45.0 (I didn't try any further back)

[imaNNeo]

Fixed in 0.62.0.
Please check it out!