bug#24560: 25.1; With `--font 7x13', wrong font is used for Unicode characters

[Eli Zaretskii]

> From: Vladimir Panteleev <thecybershadow@gmail.com>
> Date: Wed, 28 Sep 2016 16:34:15 +0000
> 
> On a GNU/Linux system running X.Org, if Emacs is set to use the X11
> fixed font 7x13 (e.g. by specifying `--font 7x13' on the command line),
> Emacs will use the incorrect font for Unicode (non-ASCII)
> characters. Specifically:
> 
> - US-ASCII characters are rendered using the correct font.
> 
> - Cyrillic (e.g. letters of the Russian alphabet) and some other
>   characters (e.g. '¢' (CENT SIGN)) are rendered with the 12x13 font
>   instead of the indicated 7x13 font.
> 
> - Some characters, e.g. '·' (MIDDLE DOT) and '»' (RIGHT-POINTING DOUBLE
>   ANGLE QUOTATION MARK) are rendered with an 8x13 font. This causes
>   enabling whitespace-mode to misalign text.

Are you sure the 7x13 font installed on your system supports all those
characters?  Emacs won't switch to a different font if the default
font supports the character it needs to display.

Or could it be that some customizations, either yours or site-wide,
force Emacs to use other fonts for the above characters?

> I have found that evaluating the Sexpr:
> 
> (set-fontset-font "fontset-default" 'unicode 
> "-misc-fixed-*-*-*--13-*-*-*-*-70-iso10646-1")
> 

Don't do that, this setting will cause all kinds of surprises.  To
customize the fonts, use specific character codepoint ranges, and only
specify font for a range if the font support most or all of that
range.