SwiftUI中LineChart实现多区域不同AreaMark颜色的问题

尝试为折线图的不同区域设置不同的AreaMark颜色，但均未成功。以下是两种尝试的实现方案及效果说明：

方案一代码 #

struct Value: Identifiable {
    var x: String
    var y: Int
    var color: String
    var id: UUID = UUID()
}

struct ContentView12: View {
    let data: [Value] = [
        .init(x: "0", y: 3, color: "blue"),
        .init(x: "1", y: 4, color: "blue"),
        .init(x: "2", y: 5, color: "blue"),
        .init(x: "3", y: 8, color: "blue"),
        .init(x: "4", y: -6, color: "red"),
        .init(x: "5", y: -4, color: "red"),
        .init(x: "6", y: -6, color: "red"),
        .init(x: "7", y: -8, color: "red"),
        .init(x: "8", y: 10, color: "blue"),
        .init(x: "9", y: 8, color: "blue"),
        .init(x: "10", y: 5, color: "blue"),
        .init(x: "11", y: 7, color: "blue"),
        .init(x: "12", y: 10, color: "blue")
    ]
    
    var body: some View {
        VStack {
            Chart(data) { v in
                LineMark(
                    x: .value("x", v.x),
                    y: .value("y", v.y)
                )
                .interpolationMethod(.linear)
                .foregroundStyle(Color.black)
                
                AreaMark(
                    x: .value("x", v.x),
                    y: .value("y", v.y)
                )
                .interpolationMethod(.linear)
                .foregroundStyle(by: .value("area", v.color))
            }
            .chartForegroundStyleScale([
                "red": Color.red,
                "blue": Color.blue,
                "green": Color.green
            ])
        }
        .frame(maxHeight: 300)
    }
}

效果：AreaMark未按数据中设定的颜色分区域显示，不符合预期。

方案二代码 #

Chart(lineModel) { cost in
    LineMark(
        x: .value("Date", cost.date),
        y: .value("Price", cost.amount)
    )
    AreaMark(
        x: .value("Date", cost.date),
        y: .value("Price", cost.amount),
        stacking: .unstacked
    )
    .foregroundStyle(by: .value("Price", cost.amount >= 0 ? "blue" : "red"))
}
.chartForegroundStyleScale([
    "red": Color.red,
    "blue": Color.blue
])

效果：同样未实现按数值正负分区域着色的预期，AreaMark颜色显示不符合要求。

内容的提问来源于stack exchange，提问作者Vollan