bug#46493: [feature/pgtk] Low contrast region face

[Lars Ingebrigtsen <larsi@gnus.org>]

Po Lu <luangruo@yahoo.com> writes:

>> However, we ignore the theme for everything else, so "emacs -Q" gives me
>> an Emacs with a white background -- and a very dark region face.
>
> That shouldn't be problematic, right? Because we have the distant
> foreground set to the GTK region foreground color, so there will always
> be sufficient contrast.

It's nonsensical of Emacs to use the Gtk theme for just one colour here.
It should either use the Gtk theme for the background/foreground
colours, too, or not use it at all.

> Users using a non-default GTK stylesheet should know of the
> consequences, and can simply customize the region face to use a
> different background color.

Emacs composes the colours we use here, and we choose colours that have
the mixture we want.  Our current approach leads to two bugs: With a
dark theme, we get a nonsensically dramatic region face, and with a
light theme, we get a region face that has too low contrast.  That's an
Emacs bug, and not something the user should have to deal with.

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