Re: displaying missing glyphs

[2QdxY4RzWzUUiLuE]

On 2021-04-12 at 12:08:08 -0500,
Regarding "Re: displaying missing glyphs,"
Leo Butler <leo.butler@umanitoba.ca> wrote:

> Andreas Eder <a_eder_muc@web.de> writes:
> 
> > On Fr 09 Apr 2021 at 11:32, Leo Butler <leo.butler@umanitoba.ca> wrote:
> >
> >> I use `emacs -nw` inside of screen inside of uxterm. Unfortunately, many
> >> unicode glyphs are not displayed correctly (although they are if I
> >> attach the screen session in gnome-terminal, for example).
> >>
> >> In emacs/elisp, how might I override the default empty box to display
> >> something more informative?
> >
> > The problem is - most likely - a font that is not unicode capable.
> > If you set uxterm to ise the same font as gnome-terminal then it should
> > work.
> > The same combination (uxterm, screen and emacs) works perfectly well
> > here.
> 
> Thanks for the suggestion. I have attached a marked-up screen shot of an
> xterm (left) and gnome-terminal running `emacsclient -nw` and showing
> the same buffer. You can see there is a noticeable clipping of some of
> the characters in the xterm.
> 
> According to lsof, gnome-terminal is using
> 
>  /usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf
> 
> so the xterm has been run using
> 
> xterm -fa 'DejaVuSansMono' -fs 9
> 
> (and all font-related options are commented out in ~/.Xdefaults).
> 
> FWIW, this is on a debian testing system with XTERM_LOCALE=en_US.UTF-8.

At startup time, both programs have to determine the size of a character
cell.  They do so by applying some algorithm to the font(s) involved
(the maximum width of all glyphs?  the average width of selected glyphs?
something else?).  Evidently, xterm's algorithm doesn't account for all
the glyphs, and ends up clipping some of them, whereas gnome-terminal
has a different algorithm.

You clipped the xterm and gnome-terminal windows.  Are they the same
size?  Does the gnome-terminal contain more pixels (because it accounts
for the wider glyphs)?