let graph = CPTXYGraph(frame: hostview.bounds)
        hostview.hostedGraph = graph
        graph.paddingLeft = 0.0
        graph.paddingTop = 0.0
        graph.paddingRight = 0.0
        graph.paddingBottom = 0.0
        graph.axisSet = nil

That is my code so far. I would like to plot a function. f(x) = x^2 10 should be the function value in this case. I want the x-axis and the y-axis to start at 0 and end at 100.

Can someone help me with implementing this f(x)?

CodePudding user response：

Your initialization logic of the graph should look like below. Use this in viewDidLoad

func initPlot() {
    let graph = CPTXYGraph(frame: hostView.bounds)
    graph.plotAreaFrame?.masksToBorder = false
    hostView.hostedGraph = graph
    graph.backgroundColor = UIColor.white.cgColor
    graph.paddingBottom = 40.0
    graph.paddingLeft = 40.0
    graph.paddingTop = 40.0
    graph.paddingRight = 40.0

    //configure title
    let title = "f(x) = x*x   10"
    graph.title = title
    
    //configure axes
    let axisSet = graph.axisSet as! CPTXYAxisSet

    if let x = axisSet.xAxis {
        x.majorIntervalLength   = 20
        x.minorTicksPerInterval = 1
    }

    if let y = axisSet.yAxis {
        y.majorIntervalLength   = 5
        y.minorTicksPerInterval = 5
    }

    let xMin = 0.0
    let xMax = 100.0
    let yMin = 0.0
    let yMax = 100.0
    guard let plotSpace = graph.defaultPlotSpace as? CPTXYPlotSpace else { return }
    plotSpace.xRange = CPTPlotRange(locationDecimal: CPTDecimalFromDouble(xMin), lengthDecimal: CPTDecimalFromDouble(xMax - xMin))
    plotSpace.yRange = CPTPlotRange(locationDecimal: CPTDecimalFromDouble(yMin), lengthDecimal: CPTDecimalFromDouble(yMax - yMin))
    
    //create the plot
    plot = CPTScatterPlot()
    plot.dataSource = self
    graph.add(plot, to: graph.defaultPlotSpace)
}

Additionally you need to implement CPTScatterPlotDataSource, where you define the numberOfRecords and respective X and Y values

extension ViewController: CPTScatterPlotDataSource {
    func numberOfRecords(for plot: CPTPlot) -> UInt {
        return 100
    }
    
    func number(for plot: CPTPlot, field: UInt, record: UInt) -> Any? {
        switch CPTScatterPlotField(rawValue: Int(field))! {
        case .X:
            return record
        case .Y:
            return (record * record)   10
        default:
            return 0
        }
    }
}