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bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows
From: |
Eli Zaretskii |
Subject: |
bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows |
Date: |
Sun, 10 Sep 2023 09:48:58 +0300 |
> From: Po Lu <luangruo@yahoo.com>
> Cc: shingo.fg8@gmail.com, 65803@debbugs.gnu.org
> Date: Sun, 10 Sep 2023 13:55:47 +0800
>
> Eli Zaretskii <eliz@gnu.org> writes:
>
> > No, the purpose of FRAME_COLUMN_WIDTH is much more than just "the
> > width of ASCII characters". It is used as the canonical character
> > width of the frame, for gazillion purposes. One example which
> > triggered this bug is :align-to display spec, something utterly
> > unrelated to ASCII characters.
>
> However, the column width has hitherto been defined to the average width
> of the frame font's ASCII characters. At least outside W32, that is.
No! Once again, for fixed-pitch fonts the average width is taken from
the font. Here, from ftfont.c:
if (spacing != FC_PROPORTIONAL
#ifdef FC_DUAL
&& spacing != FC_DUAL
#endif /* FC_DUAL */
)
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);
else
{
int n;
font->min_width = font->average_width = font->space_width = 0;
for (i = 32, n = 0; i < 127; i++)
if (FT_Load_Char (ft_face, i, FT_LOAD_DEFAULT) == 0)
{
int this_width = ft_face->glyph->metrics.horiAdvance >> 6;
if (this_width > 0
&& (! font->min_width || font->min_width > this_width))
font->min_width = this_width;
if (i == 32)
font->space_width = this_width;
font->average_width += this_width;
n++;
}
if (n > 0)
font->average_width /= n;
}
This clearly only calculates the average width for proportional fonts,
and otherwise takes the average width from the font's max_advance
width without calculating anything. Or what am I missing?
> > But other font back-ends don't compute average_width for fixed-pitch
> > fonts, so are you only talking about proportional fonts here?
>
> I'm talking about fonts in general: since fixed pitch fonts are meant to
> incorporate uniformly sized glyphs, the width of the space glyph should
> represent the average width of any subset of the font's glyphs. In this
> particular case, Fontconfig doesn't deem the font in question a fixed
> pitch font, and thus Emacs measures the average width of each ASCII
> character itself.
See above: other backends only calculate the average width for
proportional fonts. So what you say doesn't fit my reading of the
code.
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, (continued)
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Eli Zaretskii, 2023/09/09
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Eli Zaretskii, 2023/09/09
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Po Lu, 2023/09/09
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Eli Zaretskii, 2023/09/09
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Eli Zaretskii, 2023/09/09
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Po Lu, 2023/09/09
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Eli Zaretskii, 2023/09/10
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Po Lu, 2023/09/10
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Eli Zaretskii, 2023/09/10
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Po Lu, 2023/09/10
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows,
Eli Zaretskii <=
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Po Lu, 2023/09/10
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Eli Zaretskii, 2023/09/10
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Po Lu, 2023/09/10
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Eli Zaretskii, 2023/09/10
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Po Lu, 2023/09/10
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Eli Zaretskii, 2023/09/10
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Po Lu, 2023/09/10
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Eli Zaretskii, 2023/09/10
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Eli Zaretskii, 2023/09/10
- bug#65803: 29.1; Noto Sans Mono CJK JP has doubled-width on Windows, Po Lu, 2023/09/10