Currently this feature is still in Beta and not officially supported.
While it’s not officially supported, there’s a trick that will allow you to colour regions with gradient colours. Available from version 1.5.5.
In the colour field, manually write the colours you want to be part of your gradient separated by a
| character. For example:
The colour picker will not accept that as a valid colour, but the map will still render it. You can add as many colours as you want, separated by the
| character. In the settings page of the plugin, in the Editing tab, you can set the colour fields to be simple text inputs, to make it easier to add the color codes.
To control the direction of the gradient, in the custom JS field of the map, add the following:
let igmGradientRotation = 90;
The rotation will define the direction of the gradient.
To change the gradient type to Radial, add this to the custom JS field of the map:
let igmGradientType = 'RadialGradient';
And finally control the offset, where you can add the starting and end points of each colour:
let igmGradientOffset = [0,1];