runAt method

InlineTapRun? runAt(Offset position, { bool requireHandler = false, })

The innermost run whose boxes contain position, or null.

A pure geometric lookup — it does not stand aside for a span that owns its own recognizer, so hover and the pointer cursor still follow the enclosing link across a nested mention. Only handleEvent defers.

Implementation

InlineTapRun? runAt(Offset position, {bool requireHandler = false}) {
  if (_inlineTapRuns.isEmpty) {
    return null;
  }
  // One cheap engine call to narrow the field before measuring anything.
  // Without it every run is measured on every mouse move, which is a
  // getBoxesForSelection per link per pointer event.
  final offset = getPositionForOffset(position).offset;
  InlineTapRun? best;
  for (final run in _inlineTapRuns) {
    if (offset < run.start || offset > run.end) {
      continue;
    }
    // A run with nothing to run is not a tap target. Treating it as one lets
    // an inert TappableTextSpan nested in a link silently kill the link over
    // its own text — innermost wins, and the innermost does nothing.
    if (requireHandler && run.onTap == null) {
      continue;
    }
    final boxes = getBoxesForSelection(
      TextSelection(baseOffset: run.start, extentOffset: run.end),
      boxHeightStyle: ui.BoxHeightStyle.max,
    );
    for (final box in boxes) {
      if (box.toRect().contains(position)) {
        if (best == null || run.end - run.start < best.end - best.start) {
          best = run;
        }
        break;
      }
    }
  }
  return best;
}