Subject: bug#45799: 28.0.50; Faces shrink unreadable on GUI when foreground/background color set in TUI

From: Eli Zaretskii <[email-masked]>
Date: Tue, 12 Jan 2021 19:20:27 +0200

> Date: Tue, 12 Jan 2021 19:51:55 +0300
> From: Jean Louis <[email-masked]>
> Cc: [email-masked]
> 
> When I however, entered from xterm, from console mode with
> emacsclient -nw than after M-x customize-faces default I can see that
> height is 1 point. And it is set to 1
> 
>    [X] Height: Value Menu Height in 1/10 pt: 1                                  
> 
> that is what I see if I enter customize-faces from console by using
> server.
> 
>    [X] Height: Value Menu Height in 1/10 pt: 113
> 
> Is that normal behavior according to you?

Yes.  Everything is 1 pixel on a TTY frame.  That's why it's a bad
idea to customize faces on a TTY frame using "M-x customize-face".

> It does not sound logical that Height on console should be displayed
> as 1 as that does not relate to console height

Emacs has no way of knowing the size of font on text-mode frames, so
it counts it as 1.  That's the lowest granularity of text size on TTY
frames, as far as Emacs is concerned, as it cannot reference partial
character width or height in text mode.  The height of each text line
is 1 and the width of every character is 1 (with the exception of
double-width characters, whose width is 2).