shape static method

String shape(String input)

Implementation

static String shape(String input) {
  final runes = input.runes.toList();
  final shaped = <int>[];

  for (int i = 0; i < runes.length; i++) {
    final current = runes[i];

    final int? prev = i > 0 ? runes[i - 1] : null;
    final int? next = i < runes.length - 1 ? runes[i + 1] : null;

    final bool connectBefore =
        prev != null && _canConnectBefore(prev) && _canConnectAfter(current);
    final bool connectAfter = next != null && _canConnectAfter(next);

    final forms = _shapingTable[current];

    if (forms != null) {
      int shapedChar;
      if (forms.length == 2) {
        shapedChar = connectBefore ? forms[1] : forms[0];
      } else {
        if (!connectBefore && !connectAfter) {
          shapedChar = forms[0]; // Isolated
        } else if (!connectBefore && connectAfter) {
          shapedChar = forms[1]; // Initial
        } else if (connectBefore && connectAfter) {
          shapedChar = forms[2]; // Medial
        } else {
          shapedChar = forms[3]; // Final
        }
      }
      shaped.add(shapedChar);
    } else {
      shaped.add(current); // Leave unchanged
    }
  }

  return String.fromCharCodes(shaped.reversed);
}