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From: Po Lu <luangruo@yahoo.com>
To: Vladimir Nikishkin <lockywolf@gmail.com>
Cc: help-gnu-emacs@gnu.org
Subject: Re: A certain unicode character makes -git Emacs eat all the CPU and become very slow.
Date: Sun, 08 May 2022 16:55:12 +0800	[thread overview]
Message-ID: <87wnew4d5b.fsf@yahoo.com> (raw)
In-Reply-To: <CA+A2iZYtiiQjNjJwhoZukcDGz916_kBtBxp7cdqjCdVVoMkzZQ@mail.gmail.com> (Vladimir Nikishkin's message of "Sun, 8 May 2022 16:26:39 +0800")

Vladimir Nikishkin <lockywolf@gmail.com> writes:

> Okay, I have had some progress.
>
> The font that causes Emacs to misbehave is AdobeBlank, often shipped
> in the "Google Fonts" (not Google Noto) package.
>
> It does not have to be used for display, it is its presence that makes
> Emacs cog a core.
>
> That "Blank" font covers all of Unicode, but every glyph is an empty
> picture. I guess it is designed for the situations when there may be
> symbols from out of the installed range, but when displaying "tofu" is
> not desired, say, on public displays.
>
> But in any case, it is a fairly standard, widespread font. I don't
> think Emacs should behave like this in its presence.

I am hardly an expert in the font related code, but could you try to see
how many the function `ftfont_match' is called when the freeze happens,
with and without that font?

Thanks.



  reply	other threads:[~2022-05-08  8:55 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-05  4:03 A certain unicode character makes -git Emacs eat all the CPU and become very slow Vladimir Nikishkin
2022-05-05  5:04 ` Po Lu
2022-05-05  5:43   ` Vladimir Nikishkin
2022-05-05 10:00     ` Vladimir Nikishkin
2022-05-05 10:47       ` Po Lu
2022-05-08  8:26         ` Vladimir Nikishkin
2022-05-08  8:55           ` Po Lu [this message]
2022-05-08  8:55           ` Eli Zaretskii
2022-05-05  6:11 ` Eli Zaretskii

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