private void DetermineStepDirection(MapCoordinates start, MapCoordinates end)
{
int spanRow = Math.Abs(start.Row - end.Row);
int spanColumn = Math.Abs(start.Column - end.Column);
_dirStep = spanRow > spanColumn ? Dir.Vert : Dir.Horiz;
Dir dirOther = MapCoordinates.OtherDirection(_dirStep);
_incLong = _incShort = new MapCoordinates();
_incLong[_dirStep] = start[_dirStep] < end[_dirStep] ? 1 : -1;
_incShort[dirOther] = start[dirOther] < end[dirOther] ? 1 : -1;
_pureHorizontalOrVertical = start.Row == end.Row || start.Column == end.Column;
_largeValue = Math.Max(spanColumn, spanRow);
_smallValue = Math.Min(spanColumn, spanRow);
_tally = _largeValue / 2;
}