Re: Better handling of window margins

[martin rudalics <rudalics@gmx.at>]

 >> You say that linum-mode will specify a "display width of the same N
 >> columns in pixels".  How would it react to an increase of the width of
 >> the default face?
 >
 > How is it covered today?

Via ‘post-command-hook’ I suppose.

 >> IIUC this is not covered by any special hook so it has to be done
 >> via ‘post-command-hook’.  No great deal but it shows that
 >> ‘post-command-hook’ is indispensable for such modes.
 >
 > Even if this conclusion is correct, is it really relevant to the
 > concrete issue being discussed?

Hopefully.  If we want to get rid of ‘post-command-hook’ dependencies.
If we don't care, it's obviously not relevant.

 > If the only problems we could think
 > about, after my suggested solution is implemented, are the ones that
 > don't have any good solution now, it means the main problem -- how to
 > allow several features request display margins without stomping on
 > each other's toes -- is most probably solved.  Then the other problems
 > should be considered and solutions for them sought.
 >
 > IOW, what I suggested wasn't supposed to solve any problem except one:
 > how can several features display simultaneously on the same display
 > margin.  It wasn't supposed magically solve other related or unrelated
 > problems.

How does the ability to specify a margin size in pixels help to display
several features simultaneously?  I'm all for specifying margin sizes in
pixels.  But then I have no idea why we should keep the "character cell
units" specification.  And obviously a transit to pixel specification
has its price.

 >> So you mean there's no need for any new infrastructure here - the
 >> ‘split-window’ window parameter can take care of this.
 >
 > I simply don't believe there could be a generic solution that doesn't
 > involve active participation of the modes that are affected by this.

If modes can specify their needs for each window they act on, the
overhead will be encapsulated in calculating a window's minimum width.
If we can't manage that, then modes will also have to intervene every
time we set a window's fringes or scroll-bar width or adjust its right
trailing edge.  I'm afraid that mode authors won't want to do that.

 >>   >> When two modes simultaneously use the margins, which buffer display
 >>   >> function would be chosen?
 >>   >
 >>   > The same problem exists with the proposed solution, doesn't it?
 >>
 >> Is there one?
 >
 > Of course: imagine that the effects of 2 or more elements of the list
 > contradict each other.  Which one to choose?

I thought Joost's idea was to capture this issue by having
‘window-splittable-p’ count static margins only.  So I don't see any
contradiction.

martin