Re: Several suggestions for image support

[David Kastrup <dak@gnu.org>]

Richard Stallman <rms@gnu.org> writes:

>     However, I have fixed the treatment of newline characters
>     so that non-empty lines are no longer made a minimum
>     height equal to the frame default line height.
> 
> That could have bad effects in many cases.
>
> I don't think it is ok, unless it is limited to special conditions.

Then let us limit it to special conditions.  Line spacing is usually
used for two conflicting purposes:

a) keep material from separate lines apart
b) provide a regular grid on which lines are placed.

I have no idea what the current semantics actually are, but I'd
propose the following:

Two adjacent lines have their baselines separated by the value of line
spacing corresponding to the face that is valid for the newline
character between them unless overriden by a special "line-spacing"
property or similar.  Unless this would cause overlap of the
descenders of the upper line and the ascenders of the lower line in
which case the line distance will be increased until no overlap
occurs.

This means that for the application I have in mind, I will have to
particularly mark the newline characters as "line spacing 0".  Since
it would probably be a nuisance to require installation of a special
face here, it would be nice if we had a special text property that
could be used for the purpose of fixing the minimal line spacing.

Does this sound like a reasonable scheme?

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum