PerformanceDataPlot

PerformanceDataPlot.swift

import Foundation

public class PerformanceDataPlot {

  let xy1s: [[(x: TimeInterval, y: Double)]]
  let xy2s: [[(x: TimeInterval, y: Double)]]

  public var y1Titles: [String]
  public var y2Titles: [String]

  public var y1Label: String = ""
  public var y2Label: String = ""
  
  public init(xy1s: [[(TimeInterval, Double)]], xy2s: [[(TimeInterval, Double)]] = [])
  {
    self.xy1s = xy1s
    self.xy2s = xy2s

    self.y1Titles = Array(repeating: "", count: xy1s.count)
    self.y2Titles = Array(repeating: "", count: xy2s.count)
  }
  
  func plot(code: String) throws
  {  
    let inputPipe = Pipe()
    let inputFile = inputPipe.fileHandleForWriting
    let gnuplot = Process()
    gnuplot.executableURL = .init(fileURLWithPath: "/usr/bin/gnuplot")
    gnuplot.arguments = ["-p", "-e", code]
    gnuplot.standardInput = inputPipe
    try gnuplot.run()
    inputFile.write(plotData.data(using: .utf8)!)
  }

  public func plot(toFile: String? = nil) {
    var code: String = ""
    if let file = toFile {
        code = """
        set terminal pdf size 18,10 enhanced color font 'Helvetica,16' lw 1;
        set output \"\(file).pdf \";
        set title '\(file)';
        unset key;
        """
    } 
    code += setCommands + plotCommands
    try! plot(code: code)
  }

  var plotData: String {
    let xy1 = xy1s.map { $0.map { $0.x.description + ", " + $0.y.description }
      .joined(separator: "\n") }.joined(separator: "\ne\n") + "\ne\n"
    let xy2 = xy2s.map { $0.map { $0.x.description + ", " + $0.y.description }
      .joined(separator: "\n") }.joined(separator: "\ne\n") + "\ne\n"
    return xy1 + xy2
  }

  var setCommands: String {
    let setCommands = [      
      "grid",
      "ylabel '\(y1Label)'",
      "y2label '\(y2Label)'",
      "xlabel 'Time'",
      "style textbox opaque margins 1.0, 1.0 fc bgnd border lt -1 linewidth 1.0", 
      "xdata time",
      "timefmt '%s'",
      #"format x '%d %b'"#,
      #"xrange ["\(xy1s.first!.first!.0)":"\(xy1s.first!.last!.0)"]"#,
      "xtics 60. * 60. * 24. ",
      "xtics rotate",
      "autoscale",
      "autoscale y2",
      "style data lines",
      "ytics nomirror 10",
      "y2tics;"      
    ]
    return setCommands.map { "set " + $0 }.joined(separator: ";")
  }

  var plotCommands: String {
    let plotCommands = ["plot '-' using 1:2 title '\(y1Titles.first!)' axes x1y1 with lines linewidth 2"]
      + xy1s.indices.dropFirst().map { i in "'' using 1:2 title '\(y1Titles[i])' axes x1y1 with lines linewidth 2" }
      + xy2s.indices.map { i in "'' using 1:2 title '\(y2Titles[i])' axes x1y2 with lines linewidth 2" }     

    return plotCommands.joined(separator: ",")   
  }
}