It is very simple to use fillFunction with other types of
charts, for example, to make column green above zero and red under
zero. But it does not work for Area Chart. How can I implement
different colors to the same series of Area Chart. Thanks.
Hey, it doesn't work the way you might think. The color
returned by fillFunction will be used by the itemRenderer in a
series. But as AreaSeries does not have any itemRenderer by
default, the effect is not visible.
If you add an itemRenderer to the series, like
CircleItemRenderer/ DiamondItemRenderer/ BoxItemRenderer etc...,
then the datapoints will be shown as circles / diamonds /
rectangles etc... and you should be able to see the color in those