line-chart-widget

linechartpainter-03.dart

  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) {
    final path = Path();
    for (var i = 0; i < points.length; i++) {
      final p = points[i];
      if (i == 0) {
        path.moveTo(p.dx, p.dy);
      } else {
        path.lineTo(p.dx, p.dy);
      }
    }
    return path;
  }

  void _drawDataPoints(Canvas canvas, List<Offset> points, Paint dotPaintFill) {
    points.forEach((dp) {
      canvas.drawCircle(dp, radius, dotPaintFill);
      canvas.drawCircle(dp, radius, linePaint);
    });
  }