bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows

[Po Lu via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Eli Zaretskii <eliz@gnu.org> writes:

> Thanks, but the above snippet in ftfont.c is only done for
> proportional fonts, not for fixed-pitch fonts.  Is the font in
> question, Noto Sans Mono CJK JP, a proportional font?  That is, does
> it not set the fixed-pitch attribute?

There's no spacing attribute in TrueType fonts, so that is contingent
upon how the MS Windows font scaler detects fixed pitch fonts.  Here's
how ftfont.c calculates the average width for fonts that Fontconfig
deems fixed pitch:

    font->min_width = font->average_width = font->space_width
      = (scalable ? ft_face->max_advance_width * size / upEM + 0.5
	 : ft_face->size->metrics.max_advance >> 6);

That aside, Fontconfig does not judge Noto Sans Mono CJK JP a fixed
pitch font on my system.