Re: Modernize frame-title-format: "%b - GNU Emacs"

[Eli Zaretskii]

> From: Stefan Kangas <stefan@marxist.se>
> Date: Sun, 30 Aug 2020 16:59:39 -0700
> 
> I therefore suggest:
> 
>   (setq frame-title-format
>         '(multiple-frames "%B"
>                           ("" "%B - GNU Emacs at " system-name))
> 
> The main new feature is that we will show the current buffer or file
> name in the frame title, even when there is only one frame.
> 
> The new "%B" specifier, added by me here, is equivalent to:
> 
>   (if buffer-file-name
>       (abbreviate-file-name buffer-file-name)
>     buffer-name))

The display engine calls the function which produces the frame's title
very frequently.  You have just made redisplay much slower due to this
call (abbreviate-file-name is a large and complex function, and you
call Lisp on top of that), and caused most redisplay cycles prfoduce
more garbage.  Is it really worth it?