Text gets blurred when fl_chart is used

flutter_chart.dart

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Flutter Chart'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  @override
  void initState() {
    super.initState();
    // Timer(Duration(microseconds: 0), () {
    //   /// start the intro
    //   intro.start(context);
    // });
  }

  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          SizedBox(
            height: 20,
          ),
          Padding(
            padding: const EdgeInsets.only(left: 20.0),
            child: Text(
              "Resolved Defects Graph",
              style: TextStyle(color: Colors.black.withOpacity(0.7)),
            ),
          ),
          Container(
            height: 250,
            child: Row(
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: [
                Expanded(
                  child: Card(
                    shape: RoundedRectangleBorder(
                      borderRadius: BorderRadius.circular(15),
                    ),
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      mainAxisAlignment: MainAxisAlignment.spaceBetween,
                      children: [
                        Padding(
                          padding:
                              const EdgeInsets.only(left: 16, right: 8, top: 8),
                          child: Row(
                            mainAxisAlignment: MainAxisAlignment.spaceBetween,
                            children: [
                              Text(
                                "Resolved Defects Graph",
                                style: TextStyle(
                                    color: Colors.black.withOpacity(0.7)),
                              ),
                            ],
                          ),
                        ),
                        SizedBox(
                          height: 5,
                        ),
                        BuildsChart(),
                      ],
                    ),
                  ),
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }
}

class BuildsChart extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => BuildsChartState();
}

class BuildsChartState extends State<BuildsChart> {
  final Color barBackgroundColor = const Color(0xff72d8bf);
  final Duration animDuration = const Duration(milliseconds: 250);

  int touchedIndex;

  bool isPlaying = false;
  final List<Color> colors = [
    Colors.blueAccent,
    Colors.deepOrangeAccent,
    Colors.deepPurpleAccent,
    Colors.lightGreen,
    Colors.pinkAccent,
  ];
  final List<double> values = [20, 40, 100, 30, 50];

  @override
  Widget build(BuildContext context) {
    return Container(
      height: 180,
      margin: const EdgeInsets.symmetric(horizontal: 20.0),
      child: BarChart(
        mainBarData(),
        swapAnimationDuration: animDuration,
      ),
    );
  }

  BarChartGroupData makeGroupData(
    int x,
    double y, {
    bool isTouched = false,
    Color barColor = Colors.white,
    double width = 22,
    List<int> showTooltips = const [],
  }) {
    return BarChartGroupData(
      x: x,
      barRods: [
        BarChartRodData(
          y: 100,
          colors: [Colors.transparent],
          width: 15,
          rodStackItems: [
            BarChartRodStackItem(0, y, Colors.blueAccent),
            BarChartRodStackItem(
              y,
              100,
              Colors.grey.withOpacity(0.2),
            ),
          ],
        ),
      ],
      showingTooltipIndicators: showTooltips,
    );
  }

  List<BarChartGroupData> showingGroups() {
    List<BarChartGroupData> barChartGroupData = [];
    for (int i = 0; i < 5; i++) {
      barChartGroupData.add(
        makeGroupData(
          i,
          values[i],
          isTouched: i == touchedIndex,
          barColor: colors[i],
        ),
      );
    }
    return barChartGroupData;
  }

  BarChartData mainBarData() {
    return BarChartData(
      alignment: BarChartAlignment.spaceBetween,
      titlesData: FlTitlesData(
        show: true,
        bottomTitles: SideTitles(
          showTitles: true,
          getTextStyles: (value) => const TextStyle(
            fontSize: 12,
            color: Colors.grey,
          ),
          margin: 8,
          getTitles: (double value) {
            switch (value.toInt()) {
              case 0:
                return 'CQ1';
              case 1:
                return 'CQ2';
              case 2:
                return 'CQ3';
              case 3:
                return 'CQ4';
              case 4:
                return 'CQ5';
              default:
                return '';
            }
          },
        ),
        topTitles: SideTitles(
          showTitles: true,
          getTextStyles: (value) => const TextStyle(
            fontSize: 12,
            color: Colors.grey,
          ),
          margin: 0,
          getTitles: (double value) {
            switch (value.toInt()) {
              case 0:
                return '20';
              case 1:
                return '40';
              case 2:
                return '100';
              case 3:
                return '30';
              case 4:
                return '50';
              default:
                return '';
            }
          },
        ),
        leftTitles: SideTitles(
          showTitles: false,
        ),
      ),
      borderData: FlBorderData(
        show: false,
      ),
      barGroups: showingGroups(),
      barTouchData: BarTouchData(
        enabled: false,
      ),
    );
  }
}