Re: [PATCH] docs: sphinx-pre-install: Reword warning on installing cjk font

[Akira Yokosawa]

Hi Mauro,

On Fri, 21 May 2021 09:54:42 +0200, Mauro Carvalho Chehab wrote:
> HI Akira,
> 
> Em Fri, 21 May 2021 16:14:19 +0900
> Akira Yokosawa <akiyks@xxxxxxxxx> escreveu:
> 
>> Installing a ckj font as recommended by the warning message causes
>> generated latex code to have:
>>
>> 	% This is needed for translations
>> 	\usepackage{xeCJK}
>> 	\setCJKmainfont{Noto Sans CJK SC}
>>
>> in its preamble even for an English document.
> 
> Yes. The same LaTeX configuration is applied to all documents.
> 
> While the standard Sphinx logic allows just one conf.py, there's
> a logic on Linux that allows a per-directory configuration.
> Perhaps it would be possible to set the font just for translations.
> 
> Yet, this can't be easily done per-translation - Italian
> translation for instance doesn't need CJK fonts.

Yes, the Italian part looks ugly with xeCJK.

> 
>> The package "xeCJK" changes wide characters' appearance including
>> apostrophe (single quote) and double quotes, and it changes line-break
>> behavior with regard to the boundary of narrow and wide characters.
>>
>> This greatly degrades readability of English PDFs typeset by xelatex.
> 
> Hmm... could you give an example where it looks ugly?
> 
> At least on the documents I use to check the PDF output, I was unable
> to see any big issue.

Appended are screenshots from RCU.pdf built with and without xeCJK.

They are built on Ubuntu Bionic based container with sphinx 2.4.4.

I think you can see the difference of how apostrophes are rendered.
Line-break points are also affected by the widths of apostrophes.

Can you spot the difference?

BTW, on current docs-next, wich the CJK font installed, "make pdfdocs"
stops while building s390.pdf.

I needed to manually run "make latexdocs", then run
"latexmk -xelatex RCU.tex" under Documentation/output/latex/ to get
RCU.pdf.

        Thanks, Akira

> 
> Regards,
> Mauro
> 
>>
>> As a band-aid help, reword the message and let the user at least be
>> aware of the degradation.
>>
>> Signed-off-by: Akira Yokosawa <akiyks@xxxxxxxxx>
>> ---
[...]

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Attachment: RCU_AND_LOCKDEP_CHECKING-no_xeCJK.png
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