bool softWrap

Whether the text should break at soft line breaks.

If false, the glyphs in the text will be positioned as if there was unlimited horizontal space.

Source 

bool get softWrap => _softWrap;
void softWrap=(bool value)

Source 

set softWrap(bool value) {
  assert(value != null);
  if (_softWrap == value)
    return;
  _softWrap = value;
  markNeedsLayout();
}