Re: How to enforce unicode font for all charsets?

[Robert Pluim <rpluim@gmail.com>]

>>>>> On Fri, 13 Mar 2020 17:54:31 +0200, Eli Zaretskii <eliz@gnu.org> said:

    >> From: Sergey Organov <sorganov@gmail.com>
    >> Cc: help-gnu-emacs@gnu.org
    >> Date: Fri, 13 Mar 2020 17:54:51 +0300
    >> 
    >> > Is the snapshot you installed using the HarfBuzz library?  (If it
    >> > does, you should see it in the output of "C-u C-x =".)  If it doesn't,
    >> > please try a build that does use HarfBuzz, which is now the default
    >> > font backend in Emacs, before you decide that the issue still exists
    >> > in the latest codebase.
    >> 
    >> I didn't built it myself and have no idea what HarfBuzz is, here is the
    >> output of "C-u C-x =":
    >> 
    >> --- >8 ---
    >> position: 24 of 60 (38%), column: 23
    >> character: п (displayed as п) (codepoint 1087, #o2077, #x43f)
    >> charset: windows-1251 (WINDOWS-1251 (Cyrillic))
    >> code point in charset: 0xEF
    >> script: cyrillic
    >> syntax: w 	which means: word
    >> category: .:Base, L:Left-to-right (strong), Y:2-byte Cyrillic, c:Chinese, h:Korean, j:Japanese, y:Cyrillic
    >> to input: type "C-x 8 RET 43f" or "C-x 8 RET CYRILLIC SMALL LETTER PE"
    >> buffer code: #xD0 #xBF
    >> file code: #xD0 #xBF (encoded by coding system utf-8-unix)
    >> display: by this font (glyph code)
    >> x:-xos4-terminus-medium-r-normal--16-160-72-72-c-80-microsoft-cp1251 (#xEF)

    Eli> The output for the other string, the one with the 'unicode' charset,
    Eli> is the telltale sign.  It shouldn't show "xft" before the font name.

    Eli> Also, system-configuration-features should include "HARFBUZZ" if Emacs
    Eli> was built with HarfBuzz.

I can reproduce this with a Cairo+HarfBuzz build. Iʼm guessing itʼs
because of font-encoding-alist.

             position: 24 of 60 (38%), column: 23
            character: п (displayed as п) (codepoint 1087, #o2077, #x43f)
              charset: windows-1251 (WINDOWS-1251 (Cyrillic))
code point in charset: 0xEF
               script: cyrillic
               syntax: w 	which means: word
             category: .:Base, L:Left-to-right (strong), Y:2-byte Cyrillic, c:Chinese, h:Korean, j:Japanese, y:Cyrillic
             to input: type "C-x 8 RET 43f" or "C-x 8 RET CYRILLIC SMALL LETTER PE"
          buffer code: #xD0 #xBF
            file code: #xD0 #xBF (encoded by coding system utf-8-unix)
              display: by this font (glyph code)
    x:-xos4-terminus-medium-r-normal--28-280-72-72-c-140-microsoft-cp1251 (#xEF)

Character code properties: customize what to show
  name: CYRILLIC SMALL LETTER PE
  general-category: Ll (Letter, Lowercase)
  decomposition: (1087) ('п')

There are text properties here:
  charset              windows-1251

[back]

             position: 54 of 60 (88%), column: 23
            character: п (displayed as п) (codepoint 1087, #o2077, #x43f)
              charset: unicode (Unicode (ISO10646))
code point in charset: 0x043F
               script: cyrillic
               syntax: w 	which means: word
             category: .:Base, L:Left-to-right (strong), Y:2-byte Cyrillic, c:Chinese, h:Korean, j:Japanese, y:Cyrillic
             to input: type "C-x 8 RET 43f" or "C-x 8 RET CYRILLIC SMALL LETTER PE"
          buffer code: #xD0 #xBF
            file code: #xD0 #xBF (encoded by coding system utf-8-unix)
              display: by this font (glyph code)
    ftcrhb:-PfEd-Menlo-normal-normal-normal-*-27-*-*-*-m-0-iso10646-1 (#x375)

Character code properties: customize what to show
  name: CYRILLIC SMALL LETTER PE
  general-category: Ll (Letter, Lowercase)
  decomposition: (1087) ('п')

There are text properties here:
  charset              unicode