bug#64618: 29.0.92; Can't set Fira code font with italic type on Windows system

[Eason Huang]

Hi Emacs,

Currently I tried to use Fira Code font on Windows 10, but the italic
font can not use on Emacs 29 and Emacs 30, it rolls back to regular
font. This only happends on Windows platform. It works as expected on
macOS.

Does anyone known how to make it works?

You can downlaod and install Fira Code from this link:

https://github.com/tonsky/FiraCode/releases/download/6.2/Fira_Code_v6.2.zip

steps to reproduce:

1. Unzip the Fira_Code_v6.2.zip and install Fira Code fonts in ttf
folder

2. Start Emacs with `emacs -Q`
3. From the Menu, choose Options -> Set Default Font...
4. From the popup window, select Fira Code font with italic type
Now you will see that the font of current buffer have been changed to
Fira Code with Regular font type. It should be the italic font type.


But When I tried the Cascadia Mono font, it works as expected.
If you want install Cascadia Mono, you can download it from this link:

https://github.com/microsoft/cascadia-code/releases/download/v2111.01/CascadiaCode-2111.01.zip

-- 
Eason Huang







In GNU Emacs 29.0.92 (build 1, x86_64-w64-mingw32) of 2023-06-20 built
 on AVALON
Windowing system distributor 'Microsoft Corp.', version 10.0.19045
System Description: Microsoft Windows 10 Pro (v10.0.2009.19045.3086)

Configured using:
 'configure --with-modules --without-dbus --with-native-compilation=aot
 --without-compress-install --with-tree-sitter CFLAGS=-O2'

Configured features:
ACL GIF GMP GNUTLS HARFBUZZ JPEG JSON LCMS2 LIBXML2 MODULES NATIVE_COMP
NOTIFY W32NOTIFY PDUMPER PNG RSVG SOUND SQLITE3 THREADS TIFF
TOOLKIT_SCROLL_BARS TREE_SITTER WEBP XPM ZLIB

Important settings:
  value of $LC_CTYPE: zh_CN.UTF-8
  value of $LANG: zh_CN.UTF-8
  locale-coding-system: cp936

Major mode: ELisp/l

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  line-number-mode: t
  transient-mark-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message mailcap yank-media puny dired
dired-loaddefs rfc822 mml mml-sec password-cache epa derived epg rfc6068
epg-config gnus-util text-property-search mm-decode mm-bodies mm-encode
mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047
rfc2045 ietf-drums mm-util mail-prsvr mail-utils vc-git diff-mode
easy-mmode vc-dispatcher time-date cl-loaddefs comp comp-cstr warnings
icons subr-x rx cl-seq cl-macs gv cl-extra help-mode bytecomp
byte-compile cl-lib china-util rmc iso-transl tooltip cconv eldoc paren
electric uniquify ediff-hook vc-hooks lisp-float-type elisp-mode mwheel
dos-w32 ls-lisp disp-table term/w32-win w32-win w32-vars term/common-win
tool-bar dnd fontset image regexp-opt fringe tabulated-list replace
newcomment text-mode lisp-mode prog-mode register page tab-bar menu-bar
rfn-eshadow isearch easymenu timer select scroll-bar mouse jit-lock
font-lock syntax font-core term/tty-colors frame minibuffer nadvice seq
simple cl-generic indonesian philippine cham georgian utf-8-lang
misc-lang vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms
cp51932 hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese composite emoji-zwj charscript charprop case-table
epa-hook jka-cmpr-hook help abbrev obarray oclosure cl-preloaded button
loaddefs theme-loaddefs faces cus-face macroexp files window
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget keymap hashtable-print-readable backquote threads
w32notify w32 lcms2 multi-tty make-network-process native-compile emacs)

Memory information:
((conses 16 94994 10544)
 (symbols 48 8264 0)
 (strings 32 23639 1595)
 (string-bytes 1 685340)
 (vectors 16 17556)
 (vector-slots 8 431718 22478)
 (floats 8 46 134)
 (intervals 56 907 16)
 (buffers 984 15))