Re: Background color in SVG display

[Eli Zaretskii <eliz@gnu.org>]

> From: Pascal Quesseveur <pquessev@gmail.com>
> Date: Thu, 23 Jun 2022 12:35:25 +0200
> 
> >"EZ" == Eli Zaretskii <eliz@gnu.org> writes:
> 
>   EZ> How do you see that background?  Please show a recipe, starting
>   EZ> from "emacs -Q", that reproduces such a display of an SVG image.
> 
> I finally managed to define a minimal test:
> 
> runemacs -Q \
>  --eval="(setq initial-frame-alist (list (cons 'background-color \"azure\")))"
> 
> then visit splash.svg
> 
> The background color depends on the frame background color. It is
> light orange in this case.

I think it's your eyes that play illusion games with you.  Start
"emacs -Q" with no other arguments and move the frame of that second
Emacs near the one with splash.svg: you will see that the background
of the image is white, like the one in the second Emacs.

What happens here is that the contrast between the azure background of
the frame and the white background of the SVG image causes you to
perceive the white color as the reverse of the azure one, which is
pale red.