From: "Óscar Fuentes" <ofv@wanadoo.es>
To: martin rudalics <rudalics@gmx.at>
Cc: 50178-done@debbugs.gnu.org
Subject: bug#50178: 28.0.50; Size of echo area does not account for line-spacing
Date: Wed, 25 Aug 2021 12:49:39 +0200 [thread overview]
Message-ID: <87k0k9er3w.fsf@telefonica.net> (raw)
In-Reply-To: <a668ca4a-690e-82fd-7374-31d30b2ff9cb@gmx.at> (martin rudalics's message of "Wed, 25 Aug 2021 09:49:11 +0200")
martin rudalics <rudalics@gmx.at> writes:
>>> It must know and handle every setting that affects line height, current
>>> and future. It would be handy if Emacs provided a function that does
>>> that.
>>
>> We already have it: window-text-pixel-size.
>
> To elaborate:
>
> (1) You first have to calculate the maximum permissible pixel height of
> the echo area window from the character height of the frame where
> you intend to display the completions and the value of
> `max-mini-window-height' height as specified for that frame. Note
> that for a minibuffer-less frame the echo area window may appear on
> another frame whose character height you have to use here.
>
> (2) You then have to calculate the pixel height of each completion line
> as if it were shown in the echo area window mentioned in (1) using
> `window-text-pixel-size' and add it to some cumulative height until
> you have exhausted the maximum permissible height calculated in (1).
Thanks. That's too complicated and looks like there are quite a bit of
hidden traps, so for the time being I'll set line-spacing to nil.
On true pixel-oriented systems there are APIs for querying the display
engine about several metrics. Then you can place the text at certain
pixel coordinates. Emacs, however, is a Frankenstein system, that uses
pixels (on graphic frames) but the text positioning depends on previous
text, i.e. for vertical positioning it is a line-based, not pixel-based,
system. Therefore, when you just need to output some lines, you must
deal with pixels, translate back to lines and, to add insult to injury,
resort to post-facto information.
As useful as it would be an API that returns how many lines fit on a
given window. Or, on this case, max-mini-window-height being a true
indication of the capacity of the mini window on terms of the current
display settings, which is what the users want 99.9% of the time.
Closing.
next prev parent reply other threads:[~2021-08-25 10:49 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-24 2:08 bug#50178: 28.0.50; Size of echo area does not account for line-spacing Óscar Fuentes
2021-08-24 11:58 ` Eli Zaretskii
2021-08-24 13:34 ` Óscar Fuentes
2021-08-24 16:20 ` Eli Zaretskii
2021-08-24 17:44 ` Óscar Fuentes
2021-08-24 18:13 ` Eli Zaretskii
2021-08-24 18:38 ` Óscar Fuentes
2021-08-24 18:49 ` Eli Zaretskii
2021-08-24 19:36 ` Óscar Fuentes
2021-08-25 2:24 ` Eli Zaretskii
2021-08-25 7:49 ` martin rudalics
2021-08-25 9:01 ` Gregory Heytings
2021-08-25 10:49 ` Óscar Fuentes [this message]
2021-08-25 12:15 ` Eli Zaretskii
2021-08-25 14:33 ` Gregory Heytings
2021-08-25 17:09 ` Óscar Fuentes
2021-08-25 17:57 ` Eli Zaretskii
2021-08-25 20:10 ` Óscar Fuentes
2021-08-26 6:34 ` Eli Zaretskii
2021-08-26 7:54 ` martin rudalics
2021-08-26 8:12 ` Eli Zaretskii
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