bug#37667: 27.0.50; Tab Bar display problems with more than 5 tabs

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: 37667@debbugs.gnu.org
> Date: Mon, 14 Oct 2019 01:39:28 +0300
> 
> >> 2. Disable wrapping to the second line since it's not supported in -nw;
> >
> > Why isn't it supported on TTY frames, btw?  It seemed to me that the
> > infrastructure is there, i.e. we can have FRAME_TAB_BAR_LINES(f) > 1,
> > it's just that the code doesn't consider this possibility.
> 
> Is it possible for TTY frames to use the same code that implements
> wrapping in multi-line tab-bar on graphical displays?

I don't think I understand the question.  Which details of wrapping
multi-line tab bars seem to prevent doing the same on TTY frames?

> >> 4. Or don't truncate but allow scrolling tabs with mouse wheel;
> >
> > Yes, this could work as well (but scrolling should be possible not
> > only with the mouse).  The implementation could simply hscroll the
> > tab-bar window, including automatic hscrolling when the current tab is
> > far from the leftmost one.  Maybe this alternative is the easiest
> > one.  The only difficulty here is with TTY frames.
> 
> Maybe after adding a new option that disables multi-line
> so tabs are displayed on one line, hscrolling could help
> to center around the current tab.

I think if we keep using multi-line tab bars, we don't need to
complicate things by hscrolling.  Not yet, anyway.

> 5. There is another alternative: display arrow buttons on both sides
>    of the tab-bar, clicking on arrows will hscroll tabs.

On GUI frames, you get this for free by using the hscrolling machinery
and line truncation.

> 6. Or even better: clicking on such arrow buttons will pop up a menu of
>    remaining tabs that don't fit into one-line tab-bar.
>    This is like implemented recently for Info-history where clicking on
>    the tool-bar arrow pops up a menu of previous Info nodes.  The same way
>    clicking on the arrows on the tab-bar could pop up a menu of tabs whose
>    names don't fit into the one-line tab-bar at both sides of the current tab.

I'd leave such fancy features for future releases.  Remember: we are
waiting for this and other new features to reach some reasonable state
in order to start the Emacs 27 release cycle.