speadometerTicks.swift

struct GaugeView: View {
    func colorMix(percent: Int) -> Color {
        let p = Double(percent)
        let tempG = (100.0-p)/100
        let g: Double = tempG < 0 ? 0 : tempG
        let tempR = 1+(p-100.0)/100.0
        let r: Double = tempR < 0 ? 0 : tempR
        return Color.init(red: r, green: g, blue: 0)
    }
    
    func tick(at tick: Int, totalTicks: Int) -> some View {
        let percent = (tick * 100) / totalTicks
        let startAngle = coveredRadius/2 * -1
        let stepper = coveredRadius/Double(totalTicks)
        let rotation = Angle.degrees(startAngle + stepper * Double(tick))
        return VStack {
                   Rectangle()
                    .fill(colorMix(percent: percent))
                       .frame(width: tick % 2 == 0 ? 5 : 3,
                              height: tick % 2 == 0 ? 20 : 10) //alternet small big dash
                   Spacer()
           }.rotationEffect(rotation)
    }
    
    func tickText(at tick: Int, text: String) -> some View {
        let percent = (tick * 100) / tickCount
        let startAngle = coveredRadius/2 * -1 + 90
        let stepper = coveredRadius/Double(tickCount)
        let rotation = startAngle + stepper * Double(tick)
        return Text(text).foregroundColor(colorMix(percent: percent)).rotationEffect(.init(degrees: -1 * rotation), anchor: .center).offset(x: -115, y: 0).rotationEffect(Angle.degrees(rotation))
    }
    
    let coveredRadius: Double // 0 - 360°
    let maxValue: Int
    let steperSplit: Int
    
    private var tickCount: Int {
        return maxValue/steperSplit
    }
    
    @Binding var value: Double
    var body: some View {
        ZStack {
            ForEach(0..<tickCount*2 + 1) { tick in
                self.tick(at: tick,
                          totalTicks: self.tickCount*2)
            }
            ForEach(0..<tickCount+1) { tick in
                self.tickText(at: tick, text: "\(self.steperSplit*tick)")
            }
        }.frame(width: 300, height: 300, alignment: .center)
    }
}