[Swift][SwiftUI] actor を使って、LifeGame を作る(その5：自動進化の速度設定)

    let nextGenInterval: TimeInterval = 2

    @Published var nextGenInterval: TimeInterval = 2

struct LGBoardView: View {
    @EnvironmentObject var viewModel: LGViewModel
    @State private var selectedPattern: Int = 0

    var body: some View {
        VStack {
            Grid(horizontalSpacing: 0, verticalSpacing: 0) {
                ForEach(0..<viewModel.numY, id: \.self) { yIndex in
                    GridRow {
                        ForEach(0..<viewModel.numX, id: \.self) { xIndex in
                            let cellIndex = CellIndex(x: xIndex, y: yIndex)
                            let cellState = viewModel.cells[cellIndex] ?? .alive
                            LGCellView(cellState: cellState)
                                .animation(.default, value: cellState)
                        }
                    }
                }
            }
            Button(action: {
                Task {
                    await viewModel.doPrep()
                    await viewModel.moveToNextGen()
                    await viewModel.updateCells()
                }
            }, label: {Text("NextGen")})
            .buttonStyle(.bordered)
            .disabled(viewModel.timerPubliser != nil)
            HStack {
                Button(action: {
                    viewModel.toggleAuto()
                }, label: {Text("NextGen(Auto)")
                        .hidden()
                        .overlay {
                            Text(viewModel.timerPubliser == nil ? "NextGen(Auto)" : "Stop" )
                        }
                })
                .buttonStyle(.bordered)
                HStack {
                    Image(systemName: "hare")
                    Slider(value: $viewModel.nextGenInterval,
                           in: 0.1...3,
                           label: { Text("Interval") })
                    Image(systemName: "tortoise")
                }
            }

            Picker(selection: $selectedPattern, content: {
                Text("Blinker").tag(0)
                Text("Beacon").tag(1)
                Text("Octagon").tag(2)
            }, label: {
                Text("select pattern")
            })
            .disabled(viewModel.timerPubliser != nil)
        }
        .onAppear { Task { await viewModel.updateCells() } }
        .onChange(of: selectedPattern) { pattern in
            Task {
                switch selectedPattern {
                case 0:
                    await viewModel.modelSetup(LGBoard.setupBlinker)
                case 1:
                    await viewModel.modelSetup(LGBoard.setupBeacon)
                case 2:
                    await viewModel.modelSetup(LGBoard.setupOctagon)
                default:
                    break
                }
            }
        }
    }
}

class LGViewModel: ObservableObject {
    var board: LGBoard
    @Published var cells: [CellIndex:LGCellState] = [:]

    @Published var nextGenInterval: TimeInterval = 2 {
        didSet {
            // (1)
            self.restartAuto()
        }
    }
    // ... omit ...
    func restartAuto() {
        // (2)
        if timerPubliser == nil { return }
        // (3)
        timerPubliser = Timer.TimerPublisher(interval: nextGenInterval, runLoop: .current, mode: .default)
            .autoconnect()
            .sink(receiveValue: { newDate in
                Task {
                    await self.doPrep()
                    await self.moveToNextGen()
                    await self.updateCells()
                }
            })
    }
    // ... omit ...
}

class LGViewModel: ObservableObject {
    // ... snip ...
    let numberFormatter: NumberFormatter = {
        let nf = NumberFormatter()
        nf.numberStyle = .decimal
        nf.minimumFractionDigits = 1
        nf.maximumFractionDigits = 1
        return nf
    }()

    var nextGenIntervalString: String {
        numberFormatter.string(from: nextGenInterval as NSNumber)!
    }
    // ... snip ...
}

struct LGBoardView: View {
    @EnvironmentObject var viewModel: LGViewModel
    @State private var selectedPattern: Int = 0

    var body: some View {
        VStack {
            // ... snip ...
            HStack {
                // ... snip ...
                HStack {
                    Image(systemName: "hare")
                    // !! NEW !!
                    Text(viewModel.nextGenIntervalString)
                    Slider(value: $viewModel.nextGenInterval,
                           in: 0.1...3,
                           label: { Text("Interval") })
                    Image(systemName: "tortoise")
                }
            }
            // ... snip ...
        }
        // ... snip ...
    }
}

        HStack {
            Image(systemName: "hare")
            Text(viewModel.nextGenIntervalString)
            Slider(value: Binding(get: {
                log10(viewModel.nextGenInterval / (0.01) )
            }, set: { newValue in
                viewModel.nextGenInterval = 0.01 * pow(10.0, newValue)
            }),
                   in: 1...2.5,
                   label: { Text("Interval") })
            Image(systemName: "tortoise")
        }