thin static method

List<int> thin(List<double> centers, List<double> widths, double minGap)

Returns the indices to keep so that drawn label boxes — each centered at centers[i] with width widths[i] — do not overlap, leaving at least minGap between neighboring boxes. Greedy left-to-right; the first label in position order is always kept.

Use for axis tick labels: a measured replacement for fixed stride-thinning that adapts to actual label widths instead of guessing a step.

Implementation

static List<int> thin(
  List<double> centers,
  List<double> widths,
  double minGap,
) {
  final n = centers.length;
  if (n == 0) return const [];

  final order = List<int>.generate(n, (i) => i)
    ..sort((a, b) => centers[a].compareTo(centers[b]));
  final keep = <int>[];
  var lastRight = double.negativeInfinity;
  for (final idx in order) {
    final left = centers[idx] - widths[idx] / 2;
    final right = centers[idx] + widths[idx] / 2;
    if (left >= lastRight + minGap) {
      keep.add(idx);
      lastRight = right;
    }
  }
  keep.sort();
  return keep;
}