bug#62048: 30.0.50; Non-nil `line-spacing' takes precendence over 'line-height t text property

[Eli Zaretskii]

> From: Ihor Radchenko <yantar92@posteo.net>
> Cc: 62048@debbugs.gnu.org
> Date: Wed, 08 Mar 2023 18:26:21 +0000
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > I've updated the manual to be more accurate about this.  But other
> > than that, this is not a bug in the code.
> 
> Thanks!
> 
> I agree that the current newline 'line-height property behaviour makes sense.
> However, I still see `insert-sliced-image' inserting image with gaps as
> a bug. Would it be possible to change `insert-sliced-image' so that it
> overrides buffer-local `line-spacing' and forces no gaps?

Not easily, because the fact that the line-spacing variable affects
_all_ lines is deeply entrenched in the implementation: it computes
the corresponding metrics once and never changes that through the
entire redisplay of the window.