Re: Several suggestions for image support

[storm@cua.dk (Kim F. Storm)]

Miles Bader <miles@lsi.nec.co.jp> writes:

> David Kastrup <dak@gnu.org> writes:
> > >          nil -> use height of current face (the default)
> > >          t -> use default face height (as minimum height)
> > >          0   -> use (don't increase) actual line height
> > >          N (integer > 0)  -> use N pixels (as minimum height)
> > >          F (float > 0.0)  -> use F * current face font height
> > 
> > Is 0 a special case of N (use 0 pixels as minimum height)?
> 
> Sounds like it.

Not exactly -- the 0 value is a little special in the sense that it
_also_ tries to reposition the ascent/descent of the space glyph
so that when the cursor is on that glyph, as much as possible of the
cursor is visible.

This is different from a value > 0, as that just gives a minimum
height -- and if the space glyph is taller than that, clipping occurs.
Maybe it should also try to reposition the cursor in this case; if so,
0 would indeed be just a special case of N > 0 and F > 0.0

> 
> Maybe the description would be more clear if phrased that way, e.g. --
> 
>          N (integer)     -> use N pixels (as minimum height); note that
>                             0 will give you exactly the actual line height
> 
> > >         F (float > 0.0)  -> use F * current face font height
> >
> > If so, would it be the same as 0.0, too?
> 
> I assume that the F case is really a minimum too (really that that the
> display engine can't _not_ do that), so that sounds like it's true for
> the same reasons as the N case.

Well, it's not really true for the reasons just explained.

Another issue is whether F should be relative the current face font or
the frame default font?  I chose current font, as it enables you to
use default font when necessary, while the opposite isn't true.

-- 
Kim F. Storm <storm@cua.dk> http://www.cua.dk