window-height but taking the face into account

window-height but taking the face into account

[mbork]

Hi all,

it seems that `window-height' returns the same number irrespective of
the font size I use (set up with `text-scale-adjust').  Is it possible
to get the actual number of lines visible on the screen?  And yes, I am
aware that when different parts have different font sizes, it can get
messy etc., but I don't care about such issues -- I just want to know
how many lines are actually visible in the current window.

I think I could use something like
(floor (window-pixel-height) (window-default-line-height)).
Is there a better way?

TIA,

-- 
Marcin Borkowski
https://mbork.pl
https://crimsonelevendelightpetrichor.net/

Re: window-height but taking the face into account

[Eli Zaretskii]

> From: mbork@mbork.pl
> Date: Mon, 25 Mar 2024 17:13:38 +0100
> 
> it seems that `window-height' returns the same number irrespective of
> the font size I use (set up with `text-scale-adjust').

Yes.  Like all the window-dimension functions, it measures in units of
canonical character height, which is the height of the frame's default
face's font.

> Is it possible to get the actual number of lines visible on the
> screen?

I'd say use line-number-at for the first and the last position in the
window, then subtract the first from the last.

> I think I could use something like
> (floor (window-pixel-height) (window-default-line-height)).

This will only be correct if all the lines in the window have the same
height.

Re: window-height but taking the face into account

[Stefan Monnier via Users list for the GNU Emacs text editor]

> messy etc., but I don't care about such issues -- I just want to know
> how many lines are actually visible in the current window.

(count-lines (window-start) (window-end))?


        Stefan