resize method

void resize(int length)

Implementation

void resize(int length) {
  assert(length >= 0);

  if (length == _length) {
    return;
  }

  final oldLength = _length;

  _length = length;

  if (length > oldLength) {
    // Growing intentionally preserves cell data past the old length (so
    // it can reappear if the line was previously shrunk and is now being
    // grown back - see the tests for this behaviour). But the raw bytes
    // newly exposed by this grow may hold a wide-char lead/placeholder
    // pair that was frozen mid-pair by some earlier resize whose own
    // boundary happened to land between the two halves (e.g. a shrink to
    // a width that kept the lead but cut off its placeholder, or a
    // subsequent write at a since-shrunk width that landed on the
    // placeholder half without the lead in scope to clear alongside it).
    // Scan the whole newly exposed range - not just its last column - for
    // a dangling lead and clear it so the width-2/placeholder invariant
    // holds for every cell we just made visible again.
    for (var i = oldLength; i < length; i++) {
      if (getWidth(i) == 2 && (i + 1 >= length || getWidth(i + 1) != 0)) {
        resetCell(i);
      }
    }
  }

  for (var i = 0; i < _anchors.length; i++) {
    final anchor = _anchors[i];
    if (anchor.x > _length) {
      anchor.reposition(_length);
    }
  }
}