public class LegendWithOrderControl : Legend
{
    private Func<LegendItem[], LegendItem[]>? _orderingFunction;

    public LegendWithOrderControl(Plot plot) : base(plot)
    {
    }

    /// <summary>
    /// Sets the function used to determine the order of legend items
    /// </summary>
    /// <param name="orderingFunction">A function that takes an array of LegendItems and returns them in the desired order</param>
    public void SetOrderingFunction(Func<LegendItem[], LegendItem[]> orderingFunction)
    {
        _orderingFunction = orderingFunction;
    }

    /// <summary>
    /// Clears the custom ordering function, reverting to default ordering
    /// </summary>
    public void ClearOrderingFunction()
    {
        _orderingFunction = null;
    }

    /// <summary>
    /// Override of the base GetItems method to apply custom ordering if specified
    /// </summary>
    public override LegendItem[] GetItems()
    {
        // Get items from base implementation
        LegendItem[] items = base.GetItems();

        // Apply custom ordering if a function is set
        if (_orderingFunction != null)
        {
            return _orderingFunction(items);
        }

        return items;
    }
}