bug#18195: 24.3.92; window-screen-lines is not accurate

[Eli Zaretskii]

> Date: Tue, 05 Aug 2014 16:08:56 +0200
> From: martin rudalics <rudalics@gmx.at>
> CC: dgutov@yandex.ru, 18195@debbugs.gnu.org
> 
> > But that value is a floating-point number, so accuracy is not lost.
> 
> Text displayed may be of completely different height.

Of course.  But that's of no importance for window-screen-lines,
because its contract is to count lines in units of the height of the
font used by the default face.

The fact that the metrics of the default face is used is the reason
why I wrote that this is a slippery slope, see my other message.