additionalPositiveYOffsetFromAtomicPlaceholders method

Implementation

double additionalPositiveYOffsetFromAtomicPlaceholders() {
  if (_paragraph == null || _placeholderBoxes.isEmpty || _allPlaceholders.isEmpty) return 0.0;

  // Base paragraph height measured as sum of line heights when available.
  final double baseHeight =
      _paraLines.isEmpty ? (_paragraph?.height ?? 0.0) : _paraLines.fold<double>(0.0, (sum, lm) => sum + lm.height);

  double maxBottom = baseHeight;
  final int n = math.min(_placeholderBoxes.length, _allPlaceholders.length);
  for (int i = 0; i < n; i++) {
    final ph = _allPlaceholders[i];
    if (ph.kind != _PHKind.atomic) continue;
    final tb = _placeholderBoxes[i];
    // Map placeholder index to the corresponding render box (may be a wrapper).
    RenderBox? rb = ph.atomic;
    if (rb == null) continue;
    final RenderBoxModel? styleBox = _resolveStyleBoxForPlaceholder(rb);
    if (styleBox == null) continue;
    double extraDy = 0.0;
    final Offset? rel = CSSPositionedLayout.getRelativeOffset(styleBox.renderStyle);
    if (rel != null && rel.dy > 0) extraDy += rel.dy;
    final Offset? tr = styleBox.renderStyle.effectiveTransformOffset;
    if (tr != null && tr.dy > 0) extraDy += tr.dy;
    final double bottom = tb.bottom + extraDy;
    if (bottom > maxBottom) maxBottom = bottom;
  }
  final double extra = maxBottom - baseHeight;
  return extra > 0 ? extra : 0.0;
}