This demo shows how we can use an adapter to adaptively color X-axis tooltip based on series tooltip color, which in turn is based on whether specific data item has a value lower on higher than its predecessor.
Code
xAxis.get("tooltip").get("background").adapters.add("fill", function(fill, target) {
return series.get("tooltip").get("background").get("fill");
});
xAxis.get("tooltip").get("background").adapters.add("fill", function(fill, target) {
return series.get("tooltip").get("background").get("fill");
});
Example
See the Pen Automatically adjust X-axis tooltip color based on series by amCharts team (@amcharts) on CodePen.