/// <summary>
/// Comparator used for ordering point first by ascending X, then by ascending Y.
/// </summary>
/// <param name="other">The <see cref="Point"/> to compare.</param>
/// <returns>
/// 0 if the points are spatially equal or both empty; 1 if <paramref name="other"/> is empty or
/// if this point has a greater <see cref="X"/> value or equal X values and a greater <see cref="Y"/> value;
/// -1 if this point is empty or if <paramref name="other"/> has a greater <see cref="X"/> value or equal X values
/// and a greater <see cref="Y"/> value.
/// </returns>
/// <exception cref="ArgumentNullException">Thrown if <paramref name="other"/> is null.</exception>
public virtual Int32 CompareTo(Point other)
{
if (other == null)
{
throw new ArgumentNullException("other");
}
if (Equals(other)) // This handles the case where both are empty.
{
return(0);
}
else if (IsEmpty)
{
return(-1);
}
else if (other.IsEmpty)
{
return(1);
}
else if (Tolerance.Less(X, other.X) || Tolerance.Equal(X, other.X) && Tolerance.Less(Y, other.Y))
{
return(-1);
}
else if (Tolerance.Greater(X, other.X) || Tolerance.Equal(X, other.X) && Tolerance.Greater(Y, other.Y))
{
return(1);
}
throw new InvalidOperationException("Points cannot be compared.");
}