s.minValueScale - chartMinValue);
    }

    // If a custom range function is set, call it
    if (this.options.yRangeFunction) {
      var range = this.options.yRangeFunction({min: chartMinValue, max: chartMaxValue});
      chartMinValue = range.min;
      chartMaxValue = range.max;
    }

    if (!isNaN(chartMaxValue) && !isNaN(chartMinValue)) {
      var targetValueRange = chartMaxValue - chartMinValue;
      var valueRangeDiff = (targetValueRange - this.currentValueRange);
      var minValueDiff = (char