mirrorSymbol function

String mirrorSymbol(String symbol)

Returns the horizontal mirror of an FSW symbol key (e.g. S2e748).

Symbols that don't exist in the font — and the handful with no representable ISWA mirror — pass through unchanged.

Implementation

String mirrorSymbol(String symbol) {
  final override = _specialMirrorOverrides[symbol];
  if (override != null) return override;
  final reverse = _specialMirrorReverse[symbol];
  if (reverse != null) return reverse;
  if (_noMirrorSymbols.contains(symbol)) return symbol;
  if (!_exists(symbol)) return symbol;

  final base = symbol.substring(0, 4);
  final fill = symbol[4];
  final rotation = int.parse(symbol[5], radix: 16);
  final section = _section(base);

  final Tuple2<String, int> mirrored;
  switch (section) {
    case 'hand':
      mirrored = _mirrorHand(fill, rotation);
      break;
    case 'contact':
      mirrored = _mirrorContact(base, fill, rotation);
      break;
    case 'movement':
      mirrored = _mirrorMovement(base, fill, rotation);
      break;
    default:
      mirrored = _mirrorFace(base, fill, rotation);
  }

  final candidate = '$base${mirrored.item1}${mirrored.item2.toRadixString(16)}';
  return _exists(candidate) ? candidate : symbol;
}