Complex Hitbox

I am looking for a way to have a button have a more complex hitbox instead of rectangular or circular. Is there a way to do this?

Lemur offers nothing special over JME here so this same advice will work with any JME Spatial:

Override the collideWith() of the Geometry to do whatever special complex hit box logic you need. (If it’s based on the alpha of an image, you can compute the texture location and look at the texture, for example.)

The Lemur-specific part is that you will need to override the geometry creation for the particular component you are using for the background.

Edit: (Also note: if it’s a GUI element with text then the text box will also pick up hits by default.

How could this be done?

Literally override it. Like in the java method override meaning of the word. Create your own class that extends Geometry and then override the collideWith method

public class GeometryWithUnusualCollision extends Geometry{

    @Override
    public int collideWith(Collidable other, CollisionResults results){
        // do whatever
    }
}