Subject: Re: bug#50178: 28.0.50; Size of echo area does not account for line-spacing

From: martin rudalics <[email-masked]>
Date: Thu, 26 Aug 2021 09:54:51 +0200

> 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.

Users think in terms of lines and columns.  True pixel-oriented systems
are not convenient for editing.  A few days ago I spent a couple of
hours to remove one single line from a pdf-document using LibreOffice.
I almost succeeded.

 > 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.

Did you try with `redisplay-adhoc-scroll-in-resize-mini-windows' as
Gregory proposed?

martin