[PD] Graphical envelope generator with breakpoints

[João Pais]

a kind of first version of that is in my [jmmmp/bezier]. I had hoped of  
continue to develop it until it could have all those features, but it  
didn't happen yet (I guess I didn't need it yet).

> Hey all
>
> I'm wondering if someone implemented a graphical envelope generator
> with mouse-draggable breakpoints. I think it probably could be done
> using data structures, however my stumbling block is that I can't think
> of a way to disallow point movement to x(n) > x(n+1), respectively x(n)
> < x(n-1).
>
> Preferably, it would allow to create new breakpoints in between
> existing breakpoints (as opposed to new breakpoints being appended to
> the end of the list).
> I'm not so much looking for the perfect solution, but wondering what is
> already there.
>
> Cheers
> Roman