This is very cool! I like how you delegate the offscreen positions with a variable. I worked hard on the little distance I got, but I was planning on leaving offscreen position embedded (maybe lost) in my linear expression. And the && operator is very helpful.
Tons of thanks!
(Looks like this) >>>>> https://drive.google.com/open?id=1t9Fy57BRyzEKxbR2gncfIAf55RADu58U
t = inPoint + .5;
x = linear(time, inPoint, t, -960, 960);
[x, 540]