How do I add values to my graph in core plot swift? - ios

Question

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)?

Answer 1

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
}
}
}