bug#32143: 27.0.50; Wombat theme breaks syntax highlighting when a region is selected

bug#32143: 27.0.50; Wombat theme breaks syntax highlighting when a region is selected

[Emre Sevinç]

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The theme `wombat` breaks syntax highlighting when transient-mark-mode
is enabled, and a region is selected.

Normally, without any theme loaded, a selected region shows proper
syntax highlighting as can be seen at:

  https://imgur.com/a/INLjbqh

And when you load the theme wombat, it also shows proper syntax
highlighting when no region is selected:

  https://imgur.com/a/ULTClxl

But when you select a region after loading wombat theme, the syntax
highlighting is broken:

  https://imgur.com/a/dWfKakB

I think the reason is caused by Line 39 of wombat-theme.el:

  `(region ((,class (:background "#444444" :foreground "#f6f3e8"))))

because when I remove the ":foreground" from it:

  `(region ((,class (:background "#444444"))))

I can have proper syntax highlighting again in selected regions:

  https://imgur.com/a/9hSChSH

In GNU Emacs 27.0.50 (build 2, x86_64-pc-linux-gnu, GTK+ Version 3.22.25)
 of 2018-07-13 built on lcy01-amd64-007
Windowing system distributor 'The X.Org Foundation', version 11.0.11905000
System Description: Ubuntu 17.10

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Configured using:
 'configure --build=x86_64-linux-gnu --prefix=/usr
 '--includedir=${prefix}/include' '--mandir=${prefix}/share/man'
 '--infodir=${prefix}/share/info' --sysconfdir=/etc --localstatedir=/var
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 '--libexecdir=${prefix}/lib/x86_64-linux-gnu' --disable-maintainer-mode
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 --program-suffix=-snapshot --with-modules=yes --with-x=yes
 --with-x-toolkit=gtk3 --with-xwidgets=yes 'CFLAGS=-g -O2
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Major mode: Lisp Interaction

Minor modes in effect:
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-- 
Emre Sevinç

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bug#32143: 27.0.50; Wombat theme breaks syntax highlighting when a region is selected

[Eli Zaretskii]

> From: Emre Sevinç <emre.sevinc@gmail.com>
> Date: Fri, 13 Jul 2018 09:55:47 +0200
> 
> The theme `wombat` breaks syntax highlighting when transient-mark-mode
> is enabled, and a region is selected.
> 
> Normally, without any theme loaded, a selected region shows proper
> syntax highlighting as can be seen at:
> 
>   https://imgur.com/a/INLjbqh
> 
> And when you load the theme wombat, it also shows proper syntax
> highlighting when no region is selected:
> 
>   https://imgur.com/a/ULTClxl
> 
> But when you select a region after loading wombat theme, the syntax
> highlighting is broken:
> 
>   https://imgur.com/a/dWfKakB
> 
> I think the reason is caused by Line 39 of wombat-theme.el:
> 
>   `(region ((,class (:background "#444444" :foreground "#f6f3e8"))))
> 
> because when I remove the ":foreground" from it:
> 
>   `(region ((,class (:background "#444444"))))
> 
> I can have proper syntax highlighting again in selected regions:
> 
>   https://imgur.com/a/9hSChSH

I think if this theme wants a distinct foreground for the region, it
will always override font-lock faces, because the region highlight is
implemented via overlays, and overlays always "win" faces specified as
text properties.

Stefan, do you have any clever ideas for how to keep the foreground of
'region' without overriding the font-lock specified foreground?

bug#32143: 27.0.50; Wombat theme breaks syntax highlighting when a region is selected

[Stefan Monnier]

> Stefan, do you have any clever ideas for how to keep the foreground of
> 'region' without overriding the font-lock specified foreground?

There was the idea of allowing to specify "color-changes" instead of "colors".
E.g. we could do that by obeying the `alpha` channel of the color (tho
it is not very expressive).


        Stefan

bug#32143: 27.0.50; Wombat theme breaks syntax highlighting when a region is selected

[Eli Zaretskii]

> From: Stefan Monnier <monnier@IRO.UMontreal.CA>
> Cc: Emre Sevinç <emre.sevinc@gmail.com>,
>         32143@debbugs.gnu.org
> Date: Fri, 20 Jul 2018 08:09:33 -0400
> 
> > Stefan, do you have any clever ideas for how to keep the foreground of
> > 'region' without overriding the font-lock specified foreground?
> 
> There was the idea of allowing to specify "color-changes" instead of "colors".
> E.g. we could do that by obeying the `alpha` channel of the color (tho
> it is not very expressive).

I guess this means currently there's no way of fixing that?  Then
maybe this theme should have some FIXME to that effect.

bug#32143: 27.0.50; Wombat theme breaks syntax highlighting when a region is selected

[Lars Ingebrigtsen]

Emre Sevinç <emre.sevinc@gmail.com> writes:

> because when I remove the ":foreground" from it:
>
>   `(region ((,class (:background "#444444"))))
>
> I can have proper syntax highlighting again in selected regions:

I've now done this in Emacs 28.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no