ZedGraph extensions. - Independant Pan and Zoom Y axes - YAxis order change in GraphPane - GraphPane order change in MasterPane

ZedGraphExtensions.cs

public static class ZedGraphExtensions
{
    /// <summary>
    /// Change the Y axes order
    /// </summary>
    /// <param name="list">YAxisList</param>
    /// <param name="pane">GraphPane</param>
    /// <param name="index">index</param>
    /// <param name="relativePos">relative position</param>
    /// <returns>new index</returns>
    public static int Move(this YAxisList list, GraphPane pane, int index, int relativePos)
    {
        if (index < 0 || index >= list.Count)
            return -1;

        var axis = list[index];
        list.RemoveAt(index);

        var newIndex = index + relativePos;

        if (newIndex < 0)
            newIndex = 0;
        if (newIndex > list.Count)
            newIndex = list.Count;

        list.Insert(newIndex, axis);

        foreach (var curve in pane.CurveList)
            if (curve.YAxisIndex == newIndex)
                curve.YAxisIndex = index;
            else if (curve.YAxisIndex == index)
                curve.YAxisIndex = newIndex;

        return newIndex;
    }

    /// <summary>
    /// Change the panes order
    /// </summary>
    /// <param name="list">PaneList</param>
    /// <param name="index">index</param>
    /// <param name="relativePos">relative position</param>
    /// <returns>new index</returns>
    public static int Move(this PaneList list, int index, int relativePos)
    {
        if (index < 0 || index >= list.Count)
            return -1;

        var pane = list[index];
        list.RemoveAt(index);

        var newIndex = index + relativePos;

        if (newIndex < 0)
            newIndex = 0;
        if (newIndex > list.Count)
            newIndex = list.Count;

        list.Insert(newIndex, pane);

        return newIndex;
    }

    public static void EnableYAxesZoomPan(this ZedGraphControl z, bool enable)
    {
        if (enable)
        {
            dic.Add(z, new zBag());

            z.MouseDownEvent += z_MouseDownEvent;
            z.MouseMoveEvent += z_MouseMoveEvent;
            z.MouseUpEvent += z_MouseUpEvent;
            z.MouseWheel += z_MouseWheel;
        }
        else
        {
            dic.Remove(z);

            z.MouseDownEvent -= z_MouseDownEvent;
            z.MouseMoveEvent -= z_MouseMoveEvent;
            z.MouseUpEvent -= z_MouseUpEvent;
            z.MouseWheel -= z_MouseWheel;
        }
    }

    static bool z_MouseDownEvent(ZedGraphControl z, System.Windows.Forms.MouseEventArgs e)
    {
        if (e.Button != System.Windows.Forms.MouseButtons.Left)
            return false;

        var bag = dic[z];

        if (bag.hoveredYAxis == null)
            return false;

        bag.movedYAxisStartY = e.Location.Y;
        bag.movedYAxisMin = bag.hoveredYAxis.Scale.Min;
        bag.movedYAxisMax = bag.hoveredYAxis.Scale.Max;

        return true;
    }

    static bool z_MouseMoveEvent(ZedGraphControl z, System.Windows.Forms.MouseEventArgs e)
    {
        var pt = e.Location;
        var bag = dic[z];

        if (e.Button == System.Windows.Forms.MouseButtons.Left)
        {
            if (bag.hoveredYAxis == null)
                return false;

            var yOffset = bag.hoveredYAxis.Scale.ReverseTransform(pt.Y) - bag.hoveredYAxis.Scale.ReverseTransform(bag.movedYAxisStartY);
            bag.hoveredYAxis.Scale.Min = bag.movedYAxisMin - yOffset;
            bag.hoveredYAxis.Scale.Max = bag.movedYAxisMax - yOffset;

            z.Invalidate();
            return true;
        }

        var foundObject = findZedGraphObject(z);
        bag.hoveredYAxis = foundObject as YAxis;

        if (bag.hoveredYAxis != null)
        {
            z.Cursor = Cursors.SizeNS;
            return true;
        }

        if (z.IsShowPointValues)
        {
            z.Cursor = Cursors.Cross;
            return false;
        }

        z.Cursor = Cursors.Default;
        return true;
    }

    static void z_MouseWheel(object sender, System.Windows.Forms.MouseEventArgs e)
    {
        var z = sender as ZedGraphControl;
        var bag = dic[z];

        if (bag.hoveredYAxis == null)
            return;

        var direction = e.Delta < 1 ? -.05f : .05f;
        var increment = direction * (bag.hoveredYAxis.Scale.Max - bag.hoveredYAxis.Scale.Min);
        var newMin = bag.hoveredYAxis.Scale.Min + increment;
        var newMax = bag.hoveredYAxis.Scale.Max - increment;

        bag.hoveredYAxis.Scale.Min = newMin;
        bag.hoveredYAxis.Scale.Max = newMax;

        z.AxisChange();
        z.Invalidate();
    }

    static bool z_MouseUpEvent(ZedGraphControl z, System.Windows.Forms.MouseEventArgs e)
    {
        var bag = dic[z];
        bag.hoveredYAxis = null;

        return false;
    }

    static object findZedGraphObject(ZedGraphControl z)
    {
        var pt = z.PointToClient(Control.MousePosition);

        var foundPane = z.MasterPane.FindPane(pt);
        if (foundPane == null)
            return null;

        var bag = dic[z];
        bag.foundPane = foundPane;

        object foundObject;
        int forget;

        using (var g = z.CreateGraphics())
            if (bag.foundPane.FindNearestObject(pt, g, out foundObject, out forget))
                return foundObject;

        return null;
    }

    static Dictionary<ZedGraphControl, zBag> dic = new Dictionary<ZedGraphControl, zBag>();

    class zBag
    {
        internal GraphPane foundPane;
        internal YAxis hoveredYAxis;
        internal float movedYAxisStartY;
        internal double movedYAxisMin;
        internal double movedYAxisMax;
    }
}