I made my version of the thumbstick.
I really rushed through this, so I didn't put any comments or even rename some of the sprites, sorry.
Hope it easy enough for you to understand. (Start with setting the "MovementTest" layer and the white "Sprite" sprite to 100 opacity)
I only put mouse controls, but you can easily add touch controls.
Hopefully I'll have touch added and tested by the end of the week.
EDIT: I am aware that I could have used only one sprite instead of the 9 used on the MovementTest layer, but I guess this makes it easier to understand.... or something.