FractionalOffset translation

The translation to apply to the child, as a multiple of the size.

Source 

FractionalOffset get translation => _translation;
void translation=(FractionalOffset newTranslation)

Source 

set translation (FractionalOffset newTranslation) {
  assert(newTranslation == null || (newTranslation.dx != null && newTranslation.dy != null));
  if (_translation == newTranslation)
    return;
  _translation = newTranslation;
  markNeedsPaint();
}