findPinnedRowAtPaintedY method

@override ({double extent, TKey key, double paintedOffset})? findPinnedRowAtPaintedY(double scrollY)

The pinned header whose painted band contains scrollY. See ReorderRenderPort. Scans _sticky.headers shallowest-first (the list is ordered root to leaf) and converts paint space to sliver-local by adding constraints.scrollOffset, the same conversion paintedRowBounds performs. A gesture-time caller, so _sticky holds the last PAINTED frame's values, which is the geometry the user is looking at (see paintedRowBounds).

Filters pending-deletion rows and nothing else: NOT the make-room lifted range findRowAtPaintedY skips (L21's Decision). A drag started on a pinned header lifts that very header, and skipping it would hand the probe back to the content beneath the strip; the own-slot answer is the correct state, and a pinned strict descendant of the dragged row is refused by the resolver's cycle filter anyway, a null target that holds the current gap. The lifted skip belongs to lookups that walk the VISIBLE ORDER; this one walks the sticky set.

Implementation

@override
({TKey key, double paintedOffset, double extent})? findPinnedRowAtPaintedY(
  double scrollY,
) {
  final headers = _sticky.headers;
  if (headers.isEmpty) {
    return null;
  }
  final paintY = scrollY - constraints.scrollOffset;
  for (final sticky in headers) {
    if (paintY < sticky.pinnedY) continue;
    if (paintY >= sticky.pinnedY + sticky.extent) continue;
    if (controller.isPendingDeletion(sticky.nodeId)) continue;
    return (
      key: sticky.nodeId,
      paintedOffset: sticky.pinnedY + constraints.scrollOffset,
      extent: sticky.extent,
    );
  }
  return null;
}