Amcharts系列的自定义工具提示填充颜色

Question

默认情况下，每个小于0的值，图表的工具提示填充颜色都会变为红色。

相反，对于所有低于100的值，我都需要使用红色填充颜色。

到目前为止，我设法覆盖了amcharts默认系列的工具提示填充颜色：

series.tooltip.getFillFromObject = false;
series.tooltip.background.fill = am4core.color("#CEB1BE");

我需要这样的东西：

if (series.dataFields.valueY < 100) {
        series.tooltip.background.fill = am4core.color("#FF0000"); //red
    }
    else {
        series.tooltip.background.fill = am4core.color("#00FF00"); //green
}

我认为这是基本的javascript，但是对此我不太擅长，

谢谢！

这是一个具有Amcharts默认设置的工作片段，它将更改负值的填充颜色：

    am4core.ready(function() {

// Themes begin
        am4core.useTheme(am4themes_animated);
// Themes end

// Create chart instance
        var chart = am4core.create("chartdiv", am4charts.XYChart);
        chart.paddingRight = 20;

// Add data
        chart.data = [{
            "year": "1950",
            "value": -0.307
        }, {
            "year": "1951",
            "value": -0.168
        }, {
            "year": "1952",
            "value": -0.073
        }, {
            "year": "1953",
            "value": -0.027
        }, {
            "year": "1954",
            "value": -0.251
        }, {
            "year": "1955",
            "value": -0.281
        }, {
            "year": "1956",
            "value": -0.348
        }, {
            "year": "1957",
            "value": -0.074
        }, {
            "year": "1958",
            "value": -0.011
        }, {
            "year": "1959",
            "value": -0.074
        }, {
            "year": "1960",
            "value": -0.124
        }, {
            "year": "1961",
            "value": -0.024
        }, {
            "year": "1962",
            "value": -0.022
        }, {
            "year": "1963",
            "value": 0
        }, {
            "year": "1964",
            "value": -0.296
        }, {
            "year": "1965",
            "value": -0.217
        }, {
            "year": "1966",
            "value": -0.147
        }, {
            "year": "1967",
            "value": -0.15
        }, {
            "year": "1968",
            "value": -0.16
        }, {
            "year": "1969",
            "value": -0.011
        }, {
            "year": "1970",
            "value": -0.068
        }, {
            "year": "1971",
            "value": -0.19
        }, {
            "year": "1972",
            "value": -0.056
        }, {
            "year": "1973",
            "value": 0.077
        }, {
            "year": "1974",
            "value": -0.213
        }, {
            "year": "1975",
            "value": -0.17
        }, {
            "year": "1976",
            "value": -0.254
        }, {
            "year": "1977",
            "value": 0.019
        }, {
            "year": "1978",
            "value": -0.063
        }, {
            "year": "1979",
            "value": 0.05
        }, {
            "year": "1980",
            "value": 0.077
        }, {
            "year": "1981",
            "value": 0.12
        }, {
            "year": "1982",
            "value": 0.011
        }, {
            "year": "1983",
            "value": 0.177
        }, {
            "year": "1984",
            "value": -0.021
        }, {
            "year": "1985",
            "value": -0.037
        }, {
            "year": "1986",
            "value": 0.03
        }, {
            "year": "1987",
            "value": 0.179
        }, {
            "year": "1988",
            "value": 0.18
        }, {
            "year": "1989",
            "value": 0.104
        }, {
            "year": "1990",
            "value": 0.255
        }, {
            "year": "1991",
            "value": 0.21
        }, {
            "year": "1992",
            "value": 0.065
        }, {
            "year": "1993",
            "value": 0.11
        }, {
            "year": "1994",
            "value": 0.172
        }, {
            "year": "1995",
            "value": 0.269
        }, {
            "year": "1996",
            "value": 0.141
        }, {
            "year": "1997",
            "value": 0.353
        }, {
            "year": "1998",
            "value": 0.548
        }, {
            "year": "1999",
            "value": 0.298
        }, {
            "year": "2000",
            "value": 0.267
        }, {
            "year": "2001",
            "value": 0.411
        }, {
            "year": "2002",
            "value": 0.462
        }, {
            "year": "2003",
            "value": 0.47
        }, {
            "year": "2004",
            "value": 0.445
        }, {
            "year": "2005",
            "value": 0.47
        }];

// Create axes
        var categoryAxis = chart.xAxes.push(new am4charts.CategoryAxis());
        categoryAxis.dataFields.category = "year";
        categoryAxis.renderer.minGridDistance = 50;
        categoryAxis.renderer.grid.template.location = 0.5;
        categoryAxis.startLocation = 0.5;
        categoryAxis.endLocation = 0.5;

// Create value axis
        var valueAxis = chart.yAxes.push(new am4charts.ValueAxis());
        valueAxis.baseValue = 0;

// Create series
        var series = chart.series.push(new am4charts.LineSeries());
        series.dataFields.valueY = "value";
        series.dataFields.categoryX = "year";
        series.strokeWidth = 2;
        series.tensionX = 0.77;

// bullet is added because we add tooltip to a bullet for it to change color
        var bullet = series.bullets.push(new am4charts.Bullet());
        bullet.tooltipText = "{valueY}";

        bullet.adapter.add("fill", function(fill, target){
            if(target.dataItem.valueY < 0){
                return am4core.color("#FF0000");
            }
            return fill;
        })
        var range = valueAxis.createSeriesRange(series);
        range.value = 0;
        range.endValue = -1000;
        range.contents.stroke = am4core.color("#FF0000");
        range.contents.fill = range.contents.stroke;

// Add scrollbar
        var scrollbarX = new am4charts.XYChartScrollbar();
        scrollbarX.series.push(series);
        chart.scrollbarX = scrollbarX;

        chart.cursor = new am4charts.XYCursor();

    }); // end am4core.ready()

     #chartdiv {
         width: 100%;
         height: 500px;
     }

<script src="https://www.amcharts.com/lib/4/core.js"></script>
<script src="https://www.amcharts.com/lib/4/charts.js"></script>
<script src="https://www.amcharts.com/lib/4/themes/animated.js"></script>

<div id="chartdiv"></div>