bug#19993: 25.0.50; Unicode fonts defective on Windows

[Ilya Zakharevich]

(A) On Windows, most Unicode characters won’t be shown, even if the system 
    has (many) fonts covering the characters (and these fonts are listed in 
    `font-log'!).

(B) Documentation of fontsets is completely unusable (I will file a separate
    bug report covering this), so there is no way a user would be able to
    work around this by using “just Emacs docs”.
    
      (However, there some googlable advice — but I did not check the 
       validity of it yet)

(C) Even if a character is (eventually) shown, it may take several seconds
    after the character is typed.  E.g., typing
      ℱ
    gives a 2sec delay on my system (a pretty quick PC).  It is shown using
      uniscribe:-outline-MS 
Gothic-normal-normal-normal-mono-13-*-*-*-c-*-jisx0208*-* (#x3D3)

(D) After typing as in (C), many operations become unusable.  (E.g., showing 
    documentation for font-log takes several minutes to display the end of 
    the buffer.  Save the buffer to a file — and it takes 4.5MB.)

(E) Doing `describe-fontset' show a complete mess.  It looks like the system
    is designed for some very old installations — it has an enormous overhead
    (while not being able to show anything nontrivial!).  I get 4500 rows
    of output, containing junk like this:
          …
       ¢ .. £ (#xA2 .. #xA3)
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-1
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-2
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-3
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-4
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-9
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-10
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-13
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-14
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-15
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-16
           -*-*-*-*-*-*-*-*-*-*-*-*-viscii1.1-1
           -*-*-*-*-*-*-*-*-*-*-*-*-iso10646-1
           -*-*-*-*-*-*-*-*-*-*-*-*-jisx0208.1983-0
       ¤ (#xA4)
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-1
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-2
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-3
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-4
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-9
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-10
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-13
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-14
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-15
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-16
           -*-*-*-*-*-*-*-*-*-*-*-*-viscii1.1-1
           -*-*-*-*-*-*-*-*-*-*-*-*-iso10646-1
           -*-*-*-*-*-*-*-*-*-*-*-*-gb2312.1980-0
           -*-*-*-*-*-*-*-*-*-*-*-*-ksc5601.1987-0
       ¥ .. ¦ (#xA5 .. #xA6)
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-1
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-2
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-3
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-4
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-9
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-10
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-13
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-14
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-15
           -*-*-*-*-*-*-*-*-*-*-*-*-iso8859-16
           -*-*-*-*-*-*-*-*-*-*-*-*-viscii1.1-1
           -*-*-*-*-*-*-*-*-*-*-*-*-iso10646-1
       § (#xA7)
          …
    having no relationship to how contemporary systems are set up.

(F) `font-show-log' is a little bit more convenient to work with
     — but it shows no indication what goes wrong when Unicode
    characters are not shown.  It has 1600 lines — and, AFAICS,
    is not documented.

-----

What to do with this mess?  There should be 3 goals:

  1) fonts should work out of the box;
  
  2) one should make the list of encodings to load (I mean those in 
     `describe-fontset') system-dependent, and — on contemporary 
     systems — default to iso10646 *ONLY*.

  3) Improve the docs (but I would try to address this in a separate
     bug report).

(I keep all the debugging info I could find.  It is huge, I will make
it available upon request.)

Thanks for the parts of Emacs which ARE working great,
Ilya

=======================================================



In GNU Emacs 25.0.50.20 (i686-pc-mingw32)
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