Thanks for the response. I'll look into line-spacing.

What I'm doing is making a presentation mode (
https://bitbucket.org/zck/zpresent.el;, available on Melpa) that presents
from Emacs. I want to be able to, for example, make a title slide that
looks like this (monospaced font required for this to look right):

+--------------------------------+
|                                |
|                                |
|                                |
|       Title goes here!         |
|                                |
|    $DATE         by $PERSON    |
|                                |
|                                |
+--------------------------------+

I'm certainly open to other ways of making this look right. I don't think
doing calculations in pixels would work, unless there's a way to insert
text at a specific pixel inside Emacs. And even if there were, that seems
like a bunch more work to basically reproduce LaTeX.

On Sat, Apr 15, 2017 at 3:44 AM, Eli Zaretskii <eliz@gnu.org> wrote:

> > From: Zachary Kanfer <zkanfer@gmail.com>
> > Date: Sat, 15 Apr 2017 01:14:43 -0400
> >
> > (defun zck--window-max-lines-per-window (face &optional window)
> > "Calculate how many lines of text with face FACE can fit in WINDOW."
> > (truncate (window-body-height window t)
> > (window-font-height window face)))
>
> This doesn't take line-spacing into account, I think.
>
> What are the use cases where you need these metrics of the window?
> I'm not sure I understand the need for these facilities; e.g., why not
> do all your calculations in pixels?  Or maybe fit-window-to-buffer
> will do what you want?
>