Stacked Line Chart

ScottPlot.Plot myPlot = new();

// prepare values for each line
double[] values1 = [8.4, 6.9, 6.5, 4.4];
double[] values2 = [7.9, 6.6, 6.4, 6.2];
double[] values3 = [6.2, 7.3, 5.5, 3.7];

// create a collection holding values for each line
double[][] allValues = [values1, values2, values3];

// calculate step points for each like by storing each point twice
double[] runningSum = new double[values1.Length];
for (int i = 0; i < allValues.Length; i++)
{
    // add values on top of the running sum to achieve stacking effect
    runningSum = DataOperations.SumVertically([runningSum, allValues[i]]);

    List<Coordinates> points = [];
    for (int j = 0; j < runningSum.Length; j++)
    {
        points.Add(new(j, runningSum[j]));
        points.Add(new(j + 1, runningSum[j]));
    }

    // plot the points as it is to show a line
    Coordinates[] lineCoordinates = [.. points];

    // add the start and end points
    points.Add(new(points.Last().X, 0));
    points.Add(new(points.First().X, 0));
    Coordinates[] fillCoordinates = [.. points];

    // add the polygon then top it with a line
    var line = myPlot.Add.ScatterLine(lineCoordinates);
    line.Color = ScottPlot.Palette.Default.GetColor(i);
    line.LineWidth = 2;

    var poly = myPlot.Add.Polygon(fillCoordinates);
    poly.FillColor = line.Color.Lighten(.5);
    poly.LineWidth = 0;
}

// reverse the order of everything so the smallest polygons
// (the first that were added) to be displayed on top and rendered last
myPlot.PlottableList.Reverse();

// use tight margins to prevent padding between the data and edge of the plot
myPlot.Axes.Margins(0, 0, 0, 0.1);

// add group labels
double[] positions = [0.5, 1.5, 2.5, 3.5];
string[] labels = { "Alfred", "Ralph", "Don", "James" };
myPlot.Axes.Bottom.SetTicks(positions, labels);

myPlot.SavePng("demo.png", 400, 300);