Add a fit curve to a line/scatter plot in Grapher via automation

Each of Grapher's support fit types can be added via automation. See the AddFit and grfFitTypes help pages for additional details about the available options. The sample script below creates a few different fit curves and adjusts the properties of each.

To run this script:

1. Click here to download the BAS file: fits.BAS.
2. Click Automation | Scripts | Run, select the BAS file from your downloads directory, and click Open.

OR:

1. Copy the script below.
2. Open Grapher and turn on the Script Manager by clicking View | Display | Script Manager.
3. Press Ctrl+A to select all of the existing lines in the Script Manager and then press DELETE.
4. Press Ctrl+V to paste it into the Script Manager.
5. Click the green arrow Start/Resume icon  in the Script Manager.
    

Sub Main

 Dim GrapherApp, Docs, Plot, ScatterPlot As Object
 Set GrapherApp = CreateObject("Grapher.Application")
 GrapherApp.Visible = True
 Set Docs = GrapherApp.Documents
 Set Plot = Docs.Add(grfPlotDoc)

'Creates a line plot and assigns the graph and plot to variable names
 Set Graph = Plot.Shapes.AddLinePlotGraph(GrapherApp.Path+"\samples\tutorial.dat")
 Set ScatterPlot = Graph.Plots.Item(1)

'Adjusts the symbol and line properties for the plot
 ScatterPlot.symbolFreq = 1
 ScatterPlot.symbol.Index = 30
 ScatterPlot.symbol.size = 0.25
 ScatterPlot.symbol.color = RGB(0,0,255)
 ScatterPlot.symbol.lineColor = grfColorBlue
 ScatterPlot.line.style("invisible")

'Adds a polynomial fit curve to the plot
 Set FitPolynomial = Graph.Plots(1).AddFit(grfPolynomialFit)
 FitPolynomial.Option=4
 FitPolynomial.line.foreColor(grfColorGrassGreen)
 FitPolynomial.line.width=0.03

'Adds a spline fit curve to the plot
 Set FitSpline = Graph.Plots(1).AddFit(grfSplineFit)
 FitSpline.line.foreColor(grfColorNavyBlue)
 FitSpline.line.width=0.03
 FitSpline.Option=15

'Adds a running average fit curve to the plot
 Set FitRunningAvg = Graph.Plots(1).AddFit(grfRunningAvgFit)
 FitRunningAvg.line.foreColor(grfColorAutumnOrange)
 FitRunningAvg.line.width=0.03
 FitRunningAvg.Option=9

'Adds a weighted average fit curve to the plot
 Set FitWeightedAvg = Graph.Plots(1).AddFit(grfWeightedAvgFit)
 FitWeightedAvg.line.foreColor(grfColorRubyRed)
 FitWeightedAvg.line.width=0.03
 FitWeightedAvg.Option=3

End Sub

Updated August 13, 2019