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Diffstat (limited to 'tools/lib/python/kdoc/latex_fonts.py')
| -rwxr-xr-x | tools/lib/python/kdoc/latex_fonts.py | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/tools/lib/python/kdoc/latex_fonts.py b/tools/lib/python/kdoc/latex_fonts.py new file mode 100755 index 000000000000..29317f8006ea --- /dev/null +++ b/tools/lib/python/kdoc/latex_fonts.py @@ -0,0 +1,167 @@ +#!/usr/bin/env python3 +# SPDX-License-Identifier: GPL-2.0-only +# Copyright (C) Akira Yokosawa, 2024 +# +# Ported to Python by (c) Mauro Carvalho Chehab, 2025 + +""" +Detect problematic Noto CJK variable fonts. + +For "make pdfdocs", reports of build errors of translations.pdf started +arriving early 2024 [1, 2]. It turned out that Fedora and openSUSE +tumbleweed have started deploying variable-font [3] format of "Noto CJK" +fonts [4, 5]. For PDF, a LaTeX package named xeCJK is used for CJK +(Chinese, Japanese, Korean) pages. xeCJK requires XeLaTeX/XeTeX, which +does not (and likely never will) understand variable fonts for historical +reasons. + +The build error happens even when both of variable- and non-variable-format +fonts are found on the build system. To make matters worse, Fedora enlists +variable "Noto CJK" fonts in the requirements of langpacks-ja, -ko, -zh_CN, +-zh_TW, etc. Hence developers who have interest in CJK pages are more +likely to encounter the build errors. + +This script is invoked from the error path of "make pdfdocs" and emits +suggestions if variable-font files of "Noto CJK" fonts are in the list of +fonts accessible from XeTeX. + +References: +[1]: https://lore.kernel.org/r/8734tqsrt7.fsf@meer.lwn.net/ +[2]: https://lore.kernel.org/r/1708585803.600323099@f111.i.mail.ru/ +[3]: https://en.wikipedia.org/wiki/Variable_font +[4]: https://fedoraproject.org/wiki/Changes/Noto_CJK_Variable_Fonts +[5]: https://build.opensuse.org/request/show/1157217 + +#=========================================================================== +Workarounds for building translations.pdf +#=========================================================================== + +* Denylist "variable font" Noto CJK fonts. + - Create $HOME/deny-vf/fontconfig/fonts.conf from template below, with + tweaks if necessary. Remove leading "". + - Path of fontconfig/fonts.conf can be overridden by setting an env + variable FONTS_CONF_DENY_VF. + + * Template: +----------------------------------------------------------------- +<?xml version="1.0"?> +<!DOCTYPE fontconfig SYSTEM "urn:fontconfig:fonts.dtd"> +<fontconfig> +<!-- + Ignore variable-font glob (not to break xetex) +--> + <selectfont> + <rejectfont> + <!-- + for Fedora + --> + <glob>/usr/share/fonts/google-noto-*-cjk-vf-fonts</glob> + <!-- + for openSUSE tumbleweed + --> + <glob>/usr/share/fonts/truetype/Noto*CJK*-VF.otf</glob> + </rejectfont> + </selectfont> +</fontconfig> +----------------------------------------------------------------- + + The denylisting is activated for "make pdfdocs". + +* For skipping CJK pages in PDF + - Uninstall texlive-xecjk. + Denylisting is not needed in this case. + +* For printing CJK pages in PDF + - Need non-variable "Noto CJK" fonts. + * Fedora + - google-noto-sans-cjk-fonts + - google-noto-serif-cjk-fonts + * openSUSE tumbleweed + - Non-variable "Noto CJK" fonts are not available as distro packages + as of April, 2024. Fetch a set of font files from upstream Noto + CJK Font released at: + https://github.com/notofonts/noto-cjk/tree/main/Sans#super-otc + and at: + https://github.com/notofonts/noto-cjk/tree/main/Serif#super-otc + , then uncompress and deploy them. + - Remember to update fontconfig cache by running fc-cache. + +!!! Caution !!! + Uninstalling "variable font" packages can be dangerous. + They might be depended upon by other packages important for your work. + Denylisting should be less invasive, as it is effective only while + XeLaTeX runs in "make pdfdocs". +""" + +import os +import re +import subprocess +import textwrap +import sys + +class LatexFontChecker: + """ + Detect problems with CJK variable fonts that affect PDF builds for + translations. + """ + + def __init__(self, deny_vf=None): + if not deny_vf: + deny_vf = os.environ.get('FONTS_CONF_DENY_VF', "~/deny-vf") + + self.environ = os.environ.copy() + self.environ['XDG_CONFIG_HOME'] = os.path.expanduser(deny_vf) + + self.re_cjk = re.compile(r"([^:]+):\s*Noto\s+(Sans|Sans Mono|Serif) CJK") + + def description(self): + return __doc__ + + def get_noto_cjk_vf_fonts(self): + """Get Noto CJK fonts""" + + cjk_fonts = set() + cmd = ["fc-list", ":", "file", "family", "variable"] + try: + result = subprocess.run(cmd,stdout=subprocess.PIPE, + stderr=subprocess.PIPE, + universal_newlines=True, + env=self.environ, + check=True) + + except subprocess.CalledProcessError as exc: + sys.exit(f"Error running fc-list: {repr(exc)}") + + for line in result.stdout.splitlines(): + if 'variable=True' not in line: + continue + + match = self.re_cjk.search(line) + if match: + cjk_fonts.add(match.group(1)) + + return sorted(cjk_fonts) + + def check(self): + """Check for problems with CJK fonts""" + + fonts = textwrap.indent("\n".join(self.get_noto_cjk_vf_fonts()), " ") + if not fonts: + return None + + rel_file = os.path.relpath(__file__, os.getcwd()) + + msg = "=" * 77 + "\n" + msg += 'XeTeX is confused by "variable font" files listed below:\n' + msg += fonts + "\n" + msg += textwrap.dedent(f""" + For CJK pages in PDF, they need to be hidden from XeTeX by denylisting. + Or, CJK pages can be skipped by uninstalling texlive-xecjk. + + For more info on denylisting, other options, and variable font, run: + + tools/docs/check-variable-fonts.py -h + """) + msg += "=" * 77 + + return msg |