groupBars method

void groupBars(double fromX, double groupSpace, double barSpace)

Groups all BarDataSet objects this data object holds together by modifying the x-value of their entries. Previously set x-values of entries will be overwritten. Leaves space between bars and groups as specified by the parameters. Do not forget to call notifyDataSetChanged() on your BarChart object after calling this method.

@param fromX the starting point on the x-axis where the grouping should begin @param groupSpace the space between groups of bars in values (not pixels) e.g. 0.8f for bar width 1f @param barSpace the space between individual bars in values (not pixels) e.g. 0.1f for bar width 1f

Implementation

void groupBars(double fromX, double groupSpace, double barSpace) {
  int setCount = dataSets.length;
  if (setCount <= 1) {
    throw Exception(
        "BarData needs to hold at least 2 BarDataSets to allow grouping.");
  }

  IBarDataSet max = getMaxEntryCountSet()!;
  int maxEntryCount = max.getEntryCount();

  double groupSpaceWidthHalf = groupSpace / 2.0;
  double barSpaceHalf = barSpace / 2.0;
  double barWidthHalf = _barWidth / 2.0;

  double interval = getGroupWidth(groupSpace, barSpace);

  for (int i = 0; i < maxEntryCount; i++) {
    double start = fromX;
    fromX += groupSpaceWidthHalf;

    for (IBarDataSet set in dataSets) {
      fromX += barSpaceHalf;
      fromX += barWidthHalf;

      if (i < set.getEntryCount()) {
        BarEntry? entry = set.getEntryForIndex(i);

        if (entry != null) {
          entry.x = fromX;
        }
      }

      fromX += barWidthHalf;
      fromX += barSpaceHalf;
    }

    fromX += groupSpaceWidthHalf;
    double end = fromX;
    double innerInterval = end - start;
    double diff = interval - innerInterval;

    // correct rounding errors
    if (diff > 0 || diff < 0) {
      fromX += diff;
    }
  }

  notifyDataChanged();
}