Indy9000

class _DonutChartWidgetState extends State<DonutChartWidget> {

  late Timer timer;
  double fullAngle = 0.0;
  double secondsToComplete = 3.0;

  @override
  void initState() {
    super.initState();
    timer = Timer.periodic(Duration(milliseconds: 1000 ~/ 60), (timer) {

Indy9000

class Score {
  final double value;
  final DateTime time;
  Score(this.value, this.time);
}

Indy9000

import 'dart:math';

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

final rng = Random();
const dayCount = 7;

class MyApp extends StatelessWidget {

Indy9000

class LineChartWidget extends StatelessWidget {
  final List<Score> scores;
  const LineChartWidget(this.scores, {Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Container(
        child: CustomPaint(
      child: Container(),
      painter: LineChartPainter(scores),

Indy9000

const WeekDays = ["", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"];

class LineChartPainter extends CustomPainter {
  final List<Score> scores;
  late double _min, _max;
  late List<double> _Y;
  late List<String> _X;
  LineChartPainter(this.scores) {
    var min = double.maxFinite;
    var max = -double.maxFinite;

Indy9000

  @override
  void paint(Canvas canvas, Size size) {
    // compute the drawable chart width and height
    final drawableHeight = size.height - 2.0 * border;
    final drawableWidth = size.width - 2.0 * border;
    final hu = drawableHeight / 5.0; // height unit
    final wu = drawableWidth / _X.length.toDouble(); // width unit

    // compute box dimensions
    final boxH = hu * 3.0;

Indy9000

  List<Offset> _computePoints(Offset lt, double boxW, double boxH, double hr) {
    return _Y.map((yp) {
      final yy = boxH - (yp - _min) * hr;
      final dp = lt + Offset(0, yy);
      lt += Offset(boxW, 0);
      return dp;
    }).toList();
  }

  Path _computePath(List<Offset> points) {

Indy9000

void paint(Canvas canvas, Size size) {
    ...
      
    final hr = boxH / (_max - _min); // height per unit value
    final lt = Offset(border + boxW / 2.0, border);
    final points = _computePoints(lt, boxW, boxH, hr);
    final path = _computePath(points);
    canvas.drawPath(path, linePaint);
    _drawDataPoints(canvas, points, dotPaintFill);
}

Indy9000

  List<String> _computeLabels() {
    return _Y.map((yp) => "${yp.toStringAsFixed(1)}").toList();
  }

  void _drawYLabels(Canvas canvas, List<String> labels, List<Offset> points,
      double boxW, double top) {
    var i = 0;
    labels.forEach((label) {
      final dp = points[i];
      final dy = (dp.dy - 15.0) < top ? 15.0 : -15.0;

Indy9000

@override
void paint(Canvas canvas, Size size) {
  ...

  final labels = _computeLabels();
  _drawYLabels(canvas, labels, points, boxW, border);

  // draw x labels
  final lt1 = Offset(border + boxW / 2.0, border + 4.5 * hu);
  _drawXLabels(canvas, lt1, boxW);