Ah-ha, thanks heaps for the help you keep giving me, I’m learning heaps, so let me see if I understand what’s going on here.

You’ve used the nested containers so you can set the x position of the inner parameter to vary, then by using the children offset parameter you could match the y value of the outer container to the x value of the inner container? Out of curiosity I changed the offset back to zero, and linked the x position of the inner position to the y position of the outer container and found the project works the same, minus the viewer bug you mentioned. I’ve attached this in case you’re interested.

Then you linked the x (and hence y) position of the handle to the right crop parameter using the code

`fit(par("/77_project1_v1_1/circle_handle_right/circle_handle_right/panelx"),0,350,0,1)`

From what I can infer, the function fit(a,b,c,d,e) takes number a from range b,c into range d,e? If so, this is much easier than using the math chops I used for my cropping!

Unfortunately the curve I need to use to constrain the handles to can’t be written in the form y=f(x), but is just some (x,y) points. Suppose instead of the lines y=x, we just had the points (0,0), (1,1), (2,4), (3,2) connected together by lines. Would we be able to constrain the handles to that? The actual curve I have to use is made up of over 1000 points, so hopefully there’s a simple way to do it?

y=x constrained.tox|attachment (90.4 KB)