void DrawInternal(TextWriter stream, IReadOnlyGrid <TCell> grid, IEnumerable <Point> possibleMovePoints, TCell owner)
{
var possibleMovePointSet = new HashSet <Point>(possibleMovePoints);
for (int y = 0; y < grid.Height; y++)
{
for (int x = 0; x < grid.Width; x++)
{
if (possibleMovePointSet.Contains(new Point(x, y)))
{
stream.Write(possibleMovePointCharacter);
}
else
{
var cell = grid.GetCell(x, y);
stream.Write(cellCharacterMap[cell]);
}
}
stream.WriteLine();
}
}