I am trying to get a shadows on three sides of my panel except the top side. There is already a shadow component but unfortunately it only works on the X and Y axis.
I would like the power to do this produce similar to this:
You could just put a sprite/image behind the button or ui element.
The source code for Outline.cs can be found here:
https://github.com/Unity-Technologies/uGUI
Specifically:
You could take that code, rename the file and the class to your own name, put it in your project and hack it to remove the outline-upwards part. It doesn’t look too complicated.