bug#51556: 29.0.50; Poor contrast of Customize SVG icons with dark backgrounds

[Eli Zaretskii]

> From: Kévin Le Gouguec <kevin.legouguec@gmail.com>
> Cc: 51556@debbugs.gnu.org
> Date: Mon, 01 Nov 2021 21:10:13 +0100
> 
> Or is there a way for themes to define sets of icons?

In some cases, yes.  For example, on the tool bar and the tab bar.

> "(elisp) Custom
> Themes" describes custom-theme-set-variables and custom-theme-set-faces,
> but I couldn't find anything related to icons.
> 
> Or are you suggesting adding the ability for themes to include sets of
> icons?

If that's what it will take, yes.

> That seems a bit heavy-handed to me; I don't think a lot of
> theme authors will want to bother with SVG editing.

The default will be to use the existing icons, as we did before.

> For the purposes of this bug, merely letting themes customize the
> icon color (through faces) ought to be enough?

That will only affect the background, which might not be enough.