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

[Stefan Monnier <monnier@iro.umontreal.ca>]

>> I think to implement relative-visual-linum-mode efficiently, we'd need
>> help from the display engine.  E.g.:
>> - First perform redisplay of the window.
>> - then, go through the window, visual-line by visual-line
>> and add something in the margin.
>> - then update the margin part of the matrices.

> AFAIU, this would cause a momentary flickering of an incorrect display
> (without the line numbers), until they are computed and displayed.

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.

> And I still don't see any answer to my question, alas.

It's basically: linum-mode but where the line numbers are relative to
`point` rather than counting from `point-min`, and additionally it
should count visual lines (so 10 invisible lines of text don't affect
the line numbers of the text that is displayed).


        Stefan