GNU bug report logs - #76390
[PATCH] Center lines vertically with line-spacing-vertical-center

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Package: emacs;

Reported by: Daniel Mendler <mail <at> daniel-mendler.de>

Date: Tue, 18 Feb 2025 10:43:02 UTC

Severity: wishlist

Tags: patch

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From: Daniel Mendler <mail <at> daniel-mendler.de>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: 76390 <at> debbugs.gnu.org, stefankangas <at> gmail.com
Subject: bug#76390: [PATCH] Center lines vertically with line-spacing-vertical-center
Date: Tue, 18 Feb 2025 19:04:07 +0100
Eli Zaretskii <eliz <at> gnu.org> writes:

>> From: Daniel Mendler <mail <at> daniel-mendler.de>
>> Cc: 76390 <at> debbugs.gnu.org,  stefankangas <at> gmail.com
>> Date: Tue, 18 Feb 2025 16:40:15 +0100
>> 
>> Eli Zaretskii <eliz <at> gnu.org> writes:
>> 
>> > And finally, I have a question: what does this patch do with a line
>> > that mixes different fonts, especially fonts with very different
>> > values of ascent and descent?  Does the result look well?  ISTR that
>> > we need to handle the underline property specially due to these
>> > considerations, so as to avoid producing broken underline.
>> 
>> I cannot tell yet. I can answer that when I worked a little bit on the
>> patch. All I can say confidently is that the status quo with the
>> non-centered line-spacing does not look good, not even with a single
>> font (see my hi-lock example from above).
>
> "Good" in that case is in the eyes of the beholder, because the added
> spacing is uniform whatever the font.  You say "not good" because I'm
> guessing you don't like the effect in general, not because it breaks
> when different fonts are used on the same screen line.

Yes, it depends on preference. Therefore I am suggesting to add a
customization option, e.g., `line-spacing-align', or alternatively
extend the `line-spacing' variable as you suggested, such that the
feature must be enabled explicitly.

I rarely use multiple fonts on a single line. But I agree that multiple
fonts should be supported well if a `line-spacing-align' patch gets
merged, given that some themes use fonts instead of colors for font
locking. Stefan Monnier mentioned this in the thread about adding new
semantic faces.

Daniel




This bug report was last modified 115 days ago.

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