bug#47686: Live preview of setting face color

[Daniel Martín]

scame via "Bug reports for GNU Emacs, the Swiss army knife of text
editors" <bug-gnu-emacs@gnu.org> writes:

> The other day I changed the color of a face and usually it's an
> uncomfortable process, because only in the real context together with
> other colors it shows how well the color works, the small sample text
> is usually not enough. So it's choosing some some color, changing the
> face color, going to the real context to see if it's right and
> repeating until it is.
>
[...]
> It works, but it occured to me it could be easy to add something like this to 
> the *Colors* buffer
> which I can get with M-x list-colors-display.
>
> That buffer does nothing by itself, just show colors, so keys could be bind 
> for it to set face color:
>
> f - read a facename and set its foreground color on the fly as the user moves 
> in the *Colors*buffer as seen on the gif above
> b - the same for face background color
> c - cancel the live preview and restore the face's colors
> s - set the selected colors of face using customize
>

An alternative way to do what you want is the following:

- Place the point on the desired text whose face you want to change.
- M-x customize-face-other-window
- Accept the default.

For there, you can use the Customize interface to apply or revert
changes and see the results in the other window, instantly.