astonishing-spray-1411

readme.md

astonishing-spray-1411

Created with <3 with dartpad.dev.

main.dart

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

const Color darkBlue = Color.fromARGB(255, 18, 32, 47);

void main() {
  runApp(SizedBox(height: 200, child: HalfCircleWidget(values: [1,2,3])));
}


class HalfCircleWidget extends StatelessWidget {
  final List<double> values;

  HalfCircleWidget({required this.values});

  @override
  Widget build(BuildContext context) {
    double total = 0;
    values.forEach((value) => total += value);

    return Container(
      child: CustomPaint(
        painter: HalfCirclePainter(values: values, total: total),
        size: Size(200,200)
      ),
    );
  }
}

class HalfCirclePainter extends CustomPainter {
  final List<double> values;
  final double total;

  HalfCirclePainter({required this.values, required this.total});

  @override
  void paint(Canvas canvas, Size size) {
    final center = (Offset.zero & size).center;
    final radius = min(size.width, size.height) / 4;

    var startAngle = pi;
    for (int i = 0; i < values.length; i++) {
      final value = values[i];
      final sweepAngle = (value / total) * pi;

      final rect = Rect.fromCircle(center: center, radius: radius);
      final paint = Paint()
        ..color = Colors.blue.withGreen(60 * i)
        ..style = PaintingStyle.stroke
        ..strokeWidth = 90;

      canvas.drawArc(rect, startAngle, sweepAngle, false, paint);

      startAngle += sweepAngle;
    }
  }

  @override
  bool shouldRepaint(HalfCirclePainter oldDelegate) {
    return oldDelegate.values != values || oldDelegate.total != total;
  }
}