Re: HarfBuzz is available on MS-Windows

[Andy Moreton <andrewjmoreton@gmail.com>]

On Fri 31 May 2019, Eli Zaretskii wrote:

> The harfbuzz branch can now be built on MS-Windows, and will support
> the new 'harfbuzz' font backend if the requisite DLLs are installed.
>
> Work still continues on the branch in preparation for landing it on
> master at a later date, but I'd like at this time to ask people to try
> building the branch on Windows and report any problems they see.  Once
> the branch is built, you can test that it's working by typing "C-h h"
> and seeing whether HELLO displays correctly.

I've tested this with an MSYS2 64bit build on Windows 10. It appears to
work ok, but is noticeably slower compared to the master branch. I also
found the following minor issues:

a) On harfbuzz and master branches from "emacs -Q", a machine without
the Symbola font does not display the emoji U+1F44B WAVING HAND SIGN (no
font available). Babelmap shows that this character is available using
the built-in "Segoe UI Symbol" or "Segoe UI Emoji" fonts (or by
installing Symbola).

b) On the harfbuzz branch from "emacs -Q", the lao U+EC3 LAO VOWEL SIGN
AY and U+EC3 LAO VOWEL SIGN O characters are not displayed (no font
available). Babelmap shows that this character is available using the
built-in "Leelawadee UI" font.


I use the following to speed up finding built-in fonts on Windows 10:

  (pcase-dolist
      (`(,font-spec . ,targets)
       '(;; Unicode blocks ---------------------------------------
         ("Segoe UI Emoji"
          (#x1f900 . #x1f9ff)) ; Supplemental Symbols and Pictographs
         ;; Unicode scripts --------------------------------------
         ("Segoe UI Symbol"      braille mathematical symbol)
         ("Leelawadee UI"        khmer thai lao)
         ("Nirmala UI"           bengali devanagari gujarati kannada
          malayalam oriya sinhala tamil telugu)
         ("Microsoft Himalaya"   tibetan)
         ("Myanmar Text"         burmese)
         ("Ebrima"               ethiopic)
         ("Gadugi"               canadian-aboriginal cherokee)))
    (dolist (target targets)
      (set-fontset-font "fontset-default" target font-spec nil 'prepend)))

Perhaps the built in fonts should be added to the default mappings for
Windows 10.

    AndyM