I have an intricate design that I created using the Spiroshapes plugin. I'd like to recolor the (black) lines using a gradient - but I can't do a color replace from one layer to another, can I? I tried putting the gradient in a different layer, then selecting the black lines, then inverting the selection, switching to the layer with the gradient, and deleting. But that looks like bloody potato because there's no anti-aliasing.
Is there any way to do this?