Re: Visual font looping setup

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 21 Nov 2020 00:20:22 +0300
> From: Jean Louis <bugs@gnu.support>
> Cc: help-gnu-emacs@gnu.org
> 
> >   emacs -fn FONT-NAME
> 
> Sure it is possible to set it.
> 
> After long time of using some fonts I can see that there is certain
> pleasure effect to change the fonts, like relaxation. Process of
> selecting various fonts is tedious. Imagine starting emacs with emacs
> -fn for 30 times just to see which font is maybe better or not.

If you need to do that many times, "M-x set-frame-font RET" is better.

> Default font how I see it is always Courier and I wonder why Emacs
> selects that one by default.

Because that's how Emacs was programmed to work by default, if no
other user preferences are found.

> On every computer I have that font comes by default. It appears too
> small and too tiny to be readable.

The font and its default size are two different parameters.  You can
change the size without changing the font by having in your init file
something like

  (set-face-attribute 'default nil :height 150)

or alternatively something like

  (add-to-list 'default-frame-alist '(font . "..."))

where the string which specifies font is constructed from what
(face-font 'default) returns, with the pixel-size value (the number
after "mono" in the XLFD-formatted font name) replaced by a larger
number, as you see fit. 

> How could I change font only for dired mode? There is no face like
> dired-default or similar.

See buffer-face-mode.

> I can see that fixed-pitch is monospace but Dired is not monospace if
> I choose default font that is not monospace.

You are well-advised not to pick variable-pitch fonts for any default
face in any buffer or mode: they will not work well in Emacs.  Where
variable-pitch fonts are reasonable, Emacs generally uses them
automatically (for example, when displaying Web pages in EWW).  You
can specify which variable-pitch font to use in those cases by
customizing the variable-pitch face.

> Somehow I expect to have fixed font in those modes where it is
> necesary. Manual says fixed-pitch, I was thinking Dired would use
> fixed-pitch settings, but it uses default font as it inherits.

Don't change the default face to use a font that is not fixed-pitch,
you will be shooting yourself in the foot.