bug#58724: Consider showing the vertical border in the tab line

bug#58724: Consider showing the vertical border in the tab line

[João Guerra]

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The vertical border is not shown in the tab line. See
no-window-divider-mode.png for an example. On the other hand, the
window divider is (when using window-divider-mode). See
window-divider-mode.png for an example.

I think it would make sense to show the vertical border in the tab
line, since it is still part of the window. On the other hand, the
mode line is also part of the window but the vertical border is not
shown there. While it is possible to customize tab line to do this,
this is a minor UI detail that could be there from the start. Other
editors show their corresponding window dividers in their
corresponding tab line, which leads to a more consistent UI (albeit a
small detail).

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bug#58724: Consider showing the vertical border in the tab line

[Juri Linkov]

> The vertical border is not shown in the tab line. See
> no-window-divider-mode.png for an example. On the other hand, the
> window divider is (when using window-divider-mode). See
> window-divider-mode.png for an example.
>
> I think it would make sense to show the vertical border in the tab
> line, since it is still part of the window. On the other hand, the
> mode line is also part of the window but the vertical border is not
> shown there.

This is the reason why the vertical border is not shown in the tab line -
for consistency with the mode line and the header line.

> While it is possible to customize tab line to do this,
> this is a minor UI detail that could be there from the start. Other
> editors show their corresponding window dividers in their
> corresponding tab line, which leads to a more consistent UI (albeit a
> small detail).

Patches welcome to show the vertical border everywhere:
in the mode line, header line, tab line.

bug#58724: Consider showing the vertical border in the tab line

[João Guerra]

Is there a simple way to draw 1 pixel lines or 1 pixel spaces? I am
currently adding a vertical border in my tab-line customization with a
XPM, but that doesn't sound ideal. How's the original vertical border
drawn?

bug#58724: Consider showing the vertical border in the tab line

[Eli Zaretskii]

> Cc: 58724@debbugs.gnu.org
> From: João Guerra <joca.bt@gmail.com>
> Date: Sat, 29 Oct 2022 14:59:40 +0200
> 
> Is there a simple way to draw 1 pixel lines or 1 pixel spaces?

Not from Lisp, AFAIK.

> How's the original vertical border drawn?

See x_draw_vertical_window_border in xterm.c.

And note that any lines you draw on display need to be accounted for
it the layout code, as our display engine will most probably overwrite
it when you least expect it to.