Hi guys, I'm trying again with the graphing tools. It's been a while since I worked on this (sorry about that) but I really want to see them integrated.
So now I'm following Bert's suggestions and I'm trying with a less general approach: I'm not introducing a new scale on top of the existing one, instead I just added a "current object" slot on the number lines, and a "current object position in chart" slot that transforms from squeak's pixel to the number line scale and viceversa.
The implementation is much simpler than before but it's more uncomfortable IMHO. I think it would be best to have two "transform" functions accepting a number as argument and returning it transformed from one scale to the other. Unfortunately, it seems Etoys doesn't support this kind of functions nicely, all the examples I could find (such as #color:sees:) seem to be a little hacked and I wasn't sure if following that path was the right way to proceed.
I think the best would be for you to test it and tell me what you think. I'm attaching a project with the new number lines. Thanks!
Richo
P.S. I also renamed the project to Charts as Bert suggested