Adding Annotations combined with AxisAuto derivates turn out wierd

Hey Scott,

I really appreciate ScottPlot especially that it is so easy and simple to handle. I am trying to create a ScatterPlot with user configurable axis. In this scenario the user should be able to show a tooltip for every datapoint in the plot.

Before adding the tooltips everything looks fine:

But as soon as I add the tooltips and call AxisAuto the scaling between x-axis and y-axis changes and the x-axis goes full banana.

Hopefully you have an idea.

Cheers, Christian

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace BugSearch
{
    /// <summary>
    /// A form 1.
    /// </summary>
    ///
    /// <remarks>
    /// Cfortmann, 17.02.2021.
    /// </remarks>
    public partial class Form1 : Form
    {
        /// <summary>
        /// True if is date only, false if not.
        /// </summary>
        bool isDateOnly = true;

        /// <summary>
        /// The pre xs.
        /// </summary>
        DateTime[] preXS;

        /// <summary>
        /// The ys.
        /// </summary>
        double[] ys;

        /// <summary>
        /// Default constructor.
        /// </summary>
        ///
        /// <remarks>
        /// Cfortmann, 17.02.2021.
        /// </remarks>
        public Form1()
        {
            InitializeComponent();
            this.formsPlot1.Plot.XAxis.DateTimeFormat(true);
            int Min = 0;
            int Max = 20;
            Random randNum = new Random();
            ys = Enumerable
                .Repeat(0, 100)
                .Select(i => randNum.NextDouble() * (Max - Min) + Min)
                .ToArray();
            DateTime startTime = DateTime.Parse("11.11.2020 11:12:14");        
            preXS = Enumerable
                .Repeat(0, 100)
                .Select(i => startTime.AddHours(randNum.Next(-250, 250)))
                .ToArray();
            CreatePlot(false);
        }

        /// <summary>
        /// Creates a plot.
        /// </summary>
        ///
        /// <remarks>
        /// Cfortmann, 17.02.2021.
        /// </remarks>
        ///
        /// <param name="isDateOnly">   True if is date only, false if not. </param>
        public void CreatePlot(bool isDateOnly)
        {
            double[] xs;
            if (isDateOnly)
            {
                xs = preXS.Select(x => x.Date.ToOADate()).ToArray();
            }
            else
            {
                xs = preXS.Select(x => x.ToOADate()).ToArray();
            }
            ScottPlot.Plottable.ScatterPlot plt = new ScottPlot.Plottable.ScatterPlot(xs, ys)
            {
                Label = "test",
                Color = Color.Red,
                LineStyle = 0,
            };

            this.formsPlot1.Plot.Add(plt);
            this.RedrawGraph();
        }

        /// <summary>
        /// Event handler. Called by checkedListBox1 for selected index changed events.
        /// </summary>
        ///
        /// <remarks>
        /// Cfortmann, 17.02.2021.
        /// </remarks>
        ///
        /// <param name="sender">   Source of the event. </param>
        /// <param name="e">        Item check event information. </param>
        private void checkedListBox1_SelectedIndexChanged(object sender, ItemCheckEventArgs e)
        {
            switch (e.Index)
            { 
                /*
                case 0:
                    AddMinorGrid(e.NewValue == CheckState.Checked);
                    break;
                case 1:
                    ChangeTickFormat(e.NewValue == CheckState.Checked);
                    break;
                */
                case 2:
                    AddAnnotation(e.NewValue == CheckState.Checked);
                    break;
            }

            this.RedrawGraph();
        }

        /// <summary>
        /// Adds annotation.
        /// </summary>
        /// <para></para>
        /// <remarks>
        /// cfortmann, 04.12.2020.
        /// </remarks>
        public void AddAnnotation(bool isActive)
        {
            if (isActive)
            {
                foreach (var (preX, y) in Enumerable.Zip(preXS, ys))
                {
                    double x;
                    if (isDateOnly)
                    {
                        x = preX.Date.ToOADate();
                    }
                    else
                    {
                        x = preX.ToOADate();
                    }

                    ScottPlot.Plottable.Tooltip toolTip = this.formsPlot1.Plot.AddTooltip(y.ToString(), x, y);
                    toolTip.BorderWidth = 1;
                    toolTip.LabelPadding = 0;
                    toolTip.Font.Size = 10;
                    toolTip.ArrowSize = 8;
                }
            }
            else
            {
                var tooltips = this.formsPlot1.Plot.GetPlottables().OfType<ScottPlot.Plottable.Tooltip>().Select(toolTip => toolTip).ToList();
                tooltips.ForEach(toolTip => this.formsPlot1.Plot.Remove(toolTip));
            }

            this.RedrawGraph();
        }

        /// <summary>
        /// Redraw graph.
        /// </summary>
        ///
        /// <remarks>
        /// Cfortmann, 17.02.2021.
        /// </remarks>
        private void RedrawGraph()
        {
            this.formsPlot1.Plot.AxisAutoY();
            this.formsPlot1.Render();
        }

    ....
    }
}

PS: Thanks for your work and keep up with it.

[bclehmann]

I’m realizing now that converting things like the coordinates and sizes of the tooltip in coordinate space necessitates already knowing the axis limits…

I think the best solution is to have the tooltips not be considered at all in the axis calculation, which can be achieved by using double.NaN (although I think changing it so that it would accept null may be more appropriate). This does mean that auto-axising can cut off a tooltip, but this isn’t that much of an issue because tooltips automatically flow rightwards if there isn’t enough space on the left. One can consider a multi-pass AxisAuto function if this is a concern.

[ChrisAtVault]

thank you very much 😃 This fix works like a charm 👍