Custom Color Range with OxyPlot ScatterPlot

Question

I've been experimenting with implementing a scatter plot with oxyplot on top of my line series. Basically, I would love to color code some points on my scatter plot.

I already have the graph below created with a scatter plot and a line series:

The above point colors are created following tutorial here. Basically, I added a RangeColorAxis. The X-Axis from this graph ranges from 0 to 1 and creates the colors, as below:

        var customAxis = new RangeColorAxis { Key = "customColors" };
        customAxis.AddRange(0, 0.1, OxyColors.Red);
        customAxis.AddRange(0.1, 0.2, OxyColors.Yellow);
        customAxis.AddRange(0.2, 0.3, OxyColors.Green);
        customAxis.AddRange(0.3, 1, OxyColors.Orange);
        customAxis.AddRange(1, 1.1, OxyColors.Blue);
        OxyPlotModel.Axes.Add(customAxis);

But now, I would also like to add some color progression in the graph above. For example, from point 0.0 to 0.1, I would like color to progress from LightRed to DarkRed. From 0.1 to 0.2, I would like to transition from Light Yellow to Bright Yellow. From 0.2 to 0.3, I would like to transition from Light Green to Dark Green. And so on.

Is it possible to do this in Oxyplot? Thanks

Answer 1

Use LinearColorAxis:

public partial class MainWindow : Window
{
    public PlotModel Model { get; set; }

    public MainWindow()
    {
        InitializeComponent();

        Model = new PlotModel();

        var axis1 = new LinearColorAxis();
        axis1.Key = "ColorAxis";
        axis1.Maximum = 2 * Math.PI;
        axis1.Minimum = 0;
        axis1.Position = AxisPosition.Top;
        Model.Axes.Add(axis1);

        var s1 = new ScatterSeries();
        s1.ColorAxisKey = "ColorAxis";
        s1.MarkerSize = 8;
        s1.MarkerType = MarkerType.Circle;

        for (double x = 0; x <= 2 * Math.PI; x += 0.1)
            s1.Points.Add(new ScatterPoint(x, Math.Sin(x), double.NaN, x));

        Model.Series.Add(s1);

        DataContext = this;
    }
}

---

EDIT: You can also define your own palette:

axis1.Palette.Colors.Clear();

for (int i = 0; i < 256; i++)
    axis1.Palette.Colors.Add(OxyColor.FromArgb((byte)i, 255, 0, 0));