public override string ToString()
{
var ret = "";
for (int y = 0; y < Height; y++)
{
for (int x = 0; x < Width; x++)
{
ret += this.pixels[x][y].Value.HasValue ? this.pixels[x][y].Value.Value.Value : ' ';
}
if (y < Height - 1)
{
ret += Environment.NewLine;
}
}
return ret;
}