Let's say I have a circle in a vector art program like Inkscape. I'd like to animate this circle so that it's revealed from two opposite corners simultaneously (i.e. drawing a pair of semicircles from the top and bottom corners, which eventually meet up at the right and left corners). However, I need to record this as a gradient in order to animate it (in Unity, in this case).
I only know how to create gradients with predefined patterns, like a straight line or radial shape. Is there any way to "draw" a gradient as an arbitrary path? It can be a raster image if necessary; I just need a way to tell Unity how to reveal the image over time.