PiliPlus/lib/common/widgets/segment_progress_bar.dart

import 'package:flutter/material.dart';

class Segment {
  final double start;
  final double end;
  final Color color;
  final String? title;

  Segment(this.start, this.end, this.color, [this.title]);
}

class SegmentProgressBar extends CustomPainter {
  final double progress;
  final List<Segment> segmentColors;

  SegmentProgressBar({
    required this.progress,
    required this.segmentColors,
  });

  @override
  void paint(Canvas canvas, Size size) {
    final paint = Paint()..style = PaintingStyle.fill;

    for (int i = 0; i < segmentColors.length; i++) {
      paint.color = segmentColors[i].color;
      final segmentStart = segmentColors[i].start * size.width;
      final segmentEnd = segmentColors[i].end * size.width;
      final progressEnd = progress * size.width;

      if (progressEnd < segmentStart) {
        break;
      }

      final segmentWidth =
          (progressEnd < segmentEnd ? progressEnd : segmentEnd) - segmentStart;
      if (segmentWidth >= 0) {
        canvas.drawRect(
          Rect.fromLTWH(
            segmentStart,
            0,
            segmentWidth == 0 ? 2 : segmentWidth,
            size.height,
          ),
          paint,
        );
        if (segmentColors[i].title != null) {
          TextPainter textPainter = TextPainter(
            text: TextSpan(
              text: segmentColors[i].title,
              style: TextStyle(color: Colors.white, fontSize: 8),
            ),
            textDirection: TextDirection.ltr,
          )..layout();

          double? prevStart;
          if (i != 0) {
            prevStart = segmentColors[i - 1].start * size.width;
          }
          double textX = i == 0
              ? (segmentStart - textPainter.width) / 2
              : (segmentStart - prevStart! - textPainter.width) / 2 + prevStart;
          double textY = size.height - textPainter.height - 1;
          textPainter.paint(canvas, Offset(textX, textY));
        }
      }
    }
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) {
    return true;
  }
}