Suggestion: date widgets can differ per date. Following logic change can help it.

[linuxeasy]

  final Map<DateTime,Widget> markedDates;

  Widget _renderMarked(DateTime now) {
    if (widget.markedDates != null && widget.markedDates.length > 0) {
      for (DateTime key in widget.markedDates.keys) {
        if (key.year == now.year && key.month == now.month && key.day == now.day) {
          return widget.markedDates[key] == null
              ? widget.markedDateWidget
              : widget.markedDates[key];
        }
      }
    }
    return Container();
  }
}

See different date widgets for date 3 and 4.

Btw, awesome work guys!

[hyochan]

I've updated to 1.1.8 to support this feature check this out.