LinearScaleConv constructor

Implementation

LinearScaleConv(
  LinearScale spec,
  List<Tuple> tuples,
  String variable,
) {
  if (spec.min != null && spec.max != null) {
    min = spec.min;
    max = spec.max;
  } else {
    // Don't use the first one in case it is NaN.
    num minTmp = double.infinity;
    num maxTmp = double.negativeInfinity;
    for (var tuple in tuples) {
      final value = tuple[variable] as num;
      if (!value.isNaN) {
        minTmp = math.min(minTmp, value);
        maxTmp = math.max(maxTmp, value);
      }
    }

    // If all data are the same, the range is 10, to get a nice margin 1 and avoid
    // 0 problem.
    final range = maxTmp == minTmp ? 10 : maxTmp - minTmp;
    final marginMin = range * (spec.marginMin ?? 0.1);
    final marginMax = range * (spec.marginMax ?? 0.1);
    min = spec.min ?? minTmp - marginMin;
    max = spec.max ?? maxTmp + marginMax;
  }

  final tickCount = spec.tickCount ?? 5;

  if (spec.niceRange == true) {
    final niceRange = linearNiceRange(min!, max!, tickCount);
    min = niceRange.first;
    max = niceRange.last;
  }

  if (spec.ticks != null) {
    ticks = spec.ticks!;
  } else {
    ticks = linearNiceNumbers(min!, max!, tickCount);
  }

  title = spec.title ?? variable;
  formatter = spec.formatter ?? defaultFormatter;
}