tickIncrement function

num tickIncrement(num start, num stop, int count)

Implementation

num tickIncrement(num start, num stop, int count) {
  final double step = (stop - start) / count;
  final int power = (math.log(step) / math.ln10).floor();
  final num exp = math.pow(10, power);
  final double error = step / exp;

  if (power >= 0) {
    if (error >= _e10) {
      return 10 * exp;
    } else if (error >= _e5) {
      return 5 * exp;
    } else if (error >= _e2) {
      return 2 * exp;
    } else {
      return 1 * exp;
    }
  } else {
    final num negExp = -math.pow(10, -power);
    if (error >= _e10) {
      return negExp / 10;
    } else if (error >= _e5) {
      return negExp / 5;
    } else if (error >= _e2) {
      return negExp / 2;
    } else {
      return negExp;
    }
  }
}