Re: Shrinking mini windows to one pixel height

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 03 Mar 2018 10:06:18 +0100
> From: martin rudalics <rudalics@gmx.at>
> 
> I just noticed that one can resize mini windows down to one pixel
> which is maybe not what users want.  To reproduce with emacs -Q simply
> type C-h f and drag the modeline of the only window down with the
> mouse.  With some insistence you can make the minibuffer window almost
> disappear.
> 
> A trivial patch is attached.  I think it should go to the release
> branch but maybe the problem is too cosmetic for that.

Does the capability or making a mini window 1-pixel tall cause us any
trouble?  If not, I'd prefer not to block it, let alone do that on the
release branch.

If you feel strongly about disabling this by default, on behalf of the
innocent and the naïve, I could agree with a defcustom that would do
that.  Maybe.

In any case, limiting this to frame-char-height sounds too harsh to
me, because using a suitably selected font one could produce quite
legible text in the mini window of a significantly smaller size.
E.g., AFAIR sizes as small as half that don't even trigger
reallocation of the glyph matrices, because their original allocation
tolerates up to twice as many screen lines as determined by the
frame's default font.

Thanks.