Re: relative line numbers and folding: how to make they play along?

[Stefan Monnier]

>> Actually, I don't think there needs to be flickering if the first step
>> ("perform redisplay of window") just computes the new matrices without
>> performing any drawing.
> Since the display engine computes the number of each screen line as it
> lays them out, I don't understand why would 2 phases be needed.  I'm
> probably missing something.

If we bake it into the redisplay code, we can indeed do it "on the fly",
but if we want this feature to be implemented in Elisp it seems a lot
more tricky to avoid the 2 passes.

> So some lines will have negative numbers?

Right.

> And they change whenever point moves into a different line?

Right.  And they're different for different windows displaying the
same buffer.

> And when the window is scrolled, the numbers also change?

Well, to the extent that point probably changes when the window is
scrolled, yes.  Otherwise not necessarily.


        Stefan