SwiftUI Slider with track fill from center

CenterSlider.swift

import SwiftUI

#Preview {
    @Previewable @State var value: Double = 0.0
    VStack {
        Text("Value: \(value)")
        CenterSliderWithIcons(value: $value)
    }
    .foregroundStyle(.black)
    .padding()
    .frame(maxHeight: .infinity)
    .background(Color.init(white: 0.95))
}

struct CenterSliderWithIcons: View {
    @Binding var value: Double
    var bounds: ClosedRange<Double> = -1...1
    
    var body: some View {
        HStack {
            Image(systemName: "arrow.down")
                .symbolEffect(.bounce, options: .repeat(1),
                              isActive: value == bounds.lowerBound)
            
            CenterSlider(value: $value, bounds: bounds)
            
            Image(systemName: "arrow.up")
                .symbolEffect(.bounce, options: .repeat(1),
                              isActive: value == bounds.upperBound)
        }
    }
}

struct CenterSlider: View {
    @Binding var value: Double
    var bounds: ClosedRange<Double> = -1...1
    
    var travelLength: Double {
        bounds.upperBound - bounds.lowerBound
    }
    
    // 0 to 1 in range
    var normalizedValue: Double {
        return (value - bounds.lowerBound) / travelLength
    }
    
    var body: some View {
        Slider(value: $value, in: bounds)
            .overlay(
                GeometryReader { proxy in
                    let trackWidth = proxy.size.width - proxy.size.height
                    
                    ZStack(alignment: .leading) {
                        // track
                        RoundedRectangle(cornerRadius: proxy.size.height*0.5)
                            .fill(Color.init(white: 0.75))
                            .overlay(
                                RoundedRectangle(cornerRadius: proxy.size.height*0.5)
                                    .stroke(Color.init(white: 0.5), lineWidth: 1)
                                )

                        // inside fill
                        RoundedRectangle(cornerRadius: proxy.size.height*0.5)
                            .fill(.blue)
                            .frame(width: trackWidth * CGFloat(abs(0.5-normalizedValue)) + proxy.size.height)
                            .offset(x: (0.5*trackWidth - max(0,0.5-normalizedValue) * trackWidth))
                        
                        // thumb
                        Circle()
                            .fill(.white)
                            .offset(x: trackWidth * normalizedValue)
                            .padding(1)
                    }
                }
                .allowsHitTesting(false)
            )
    }
}