On 24/01/2023 12:50, martin rudalics wrote:
>  > The transcript attached, in case it's useful. But I guess, as per the
>  > previous discussion, this is the point where we could stop, with no
>  > further improvement feasible.
> 
> I'm afraid I don't know whether the filter worked at all.  Please try
> with the next patch two or three times to
> 
> (1) resize the frame with the mouse by two or three lines or columns or
>      both, and do
> 
> (2) 'set-face-attribute'
> 
> The idea is that (2) should not try to change the frame size by a very
> few pixels (less than the font size) only and that in the *foo*
> transcript lines starting with "xg_frame_set_char_size_return" appear
> confirming that the filter was effective.

It seems to have a different effect: the last version at least has one 
size where s-f-a changes the height by 2 line heights.

See this transcript where at the end (and multiple times before that) 
change the frame to 118x35 (per GNOME) which is 112x35 internally, and 
s-f-a changes the height to 33 (per GNOME) which is 34 internally.

The lines xg_frame_set_char_size_return do appear in the transcript.