bug#295: 23.0.60; wrong glyph widths of some Unicode codepoints

[Torsten Bronger <bronger@physik.rwth-aachen.de>]

Hallöchen!

Chong Yidong writes:

>>> The sub/superscripts are narrower than the ordinary characters if
>>> using a monospace font (monospace-13 in my case)
>>
>> IIUC your problem is that not all thsoe characters use the same font.
>> This may be due to your font not having those chars, or to Emacs doing
>> something wrong.
>>
>> Can you check again with the latest code (where some font problems
>> have been fixed)?  Use C-u C-x = to find the font used for the char at
>> point.
>
> Do you still see this problem?

Yes.  Take for example left and right German double quotes (which
are alternative interpretations of x201e and x201c):

            character: „ (8222, #o20036, #x201e)
    preferred charset: unicode (Unicode (ISO10646))
           code point: 0x201E
               syntax: . 	which means: punctuation
             to input: type "\glqq" or "\"`" with TeX
          buffer code: #xE2 #x80 #x9E
            file code: #xE2 #x80 #x9E (encoded by coding system utf-8-emacs-unix)
              display: by this font (glyph code)
        xft:-unknown-DejaVu Sans Mono-normal-normal-normal-*-17-*-*-*-m-0-iso10646-1 (#x68F)

    Character code properties: customize what to show
      name: DOUBLE LOW-9 QUOTATION MARK
      general-category: Ps (Punctuation, Open)
      old-name: LOW DOUBLE COMMA QUOTATION MARK


versus

            character: “ (8220, #o20034, #x201c)
    preferred charset: unicode (Unicode (ISO10646))
           code point: 0x201C
               syntax: . 	which means: punctuation
             category: c:Chinese h:Korean j:Japanese
             to input: type "\grqq" or "\ldq" or "\"'" with TeX
          buffer code: #xE2 #x80 #x9C
            file code: #xE2 #x80 #x9C (encoded by coding system utf-8-emacs-unix)
              display: by this font (glyph code)
        xft:-unknown-Kochi Gothic-normal-normal-normal-*-17-*-*-*-*-0-iso10646-1 (#x26C)

    Character code properties: customize what to show
      name: LEFT DOUBLE QUOTATION MARK
      general-category: Pi (Punctuation, Initial quote)
      old-name: DOUBLE TURNED COMMA QUOTATION MARK


While the first one is displayed correctly, the second one has no
anti-aliasing and is too wide.  I see the "category" item in the
second character.  Maybe this is the cause of this trouble?

Tschö,
Torsten.

-- 
Torsten Bronger, aquisgrana, europa vetus
                   Jabber ID: torsten.bronger@jabber.rwth-aachen.de