I fought with the most manual approach to this expression as I could to come up with for usable results. I know it's a really dumb way to do it though. I would love it if someone could straighten me out with this.
I have a layers that is wiggling it's y position. It has a a circle shape layer as a shadow below it. As the y position increases in value (goes down) I want the x scale of the circle layer to decrease.
It would probably be better to specify value ranges somehow? I don't know, but I realize I took the wrong approach.
This was the expression I was trying to recall. I knew I needed to map values, but I couldn't remember it for the life of me.
I posted the expression I ended up using below. The starting y position of the layer was 562 (pre-expression) and the wiggle was 75 - so I subtracted and added those values from the original value. Was there an easier (or better for the sake of changing) way to do this using "value"?
I had to map my values such that the startScale was larger than the endScale since I wanted the shadow to shrink as the item got lower to the ground.