Re: attachment points for vertical spacing dimensions

[Mark Polesky]

Well, so many extensive replies to respond to!  It's great,
but it makes for a long post, and I do hope the thread
participants read to the end; there's a lot of relevant
stuff for everyone here.  Thanks.

* * * * * * * * * *

Joe Neeman wrote:
> I would argue that the baseline is more natural then the
> bottom.  Moreover, using the baseline as a reference point
> will result in more even spacing of multiple consecutive
> lines of markup.

Okay, that's a good point, so I agree -- baseline is better
than bottom.  But do you agree with Carl and Trevor that we
should always use the same reference point for markups?  I
was specifically proposing to use the bottom of the upper
markup and the top of the lower markup for
between-title-spacing, but Carl argued eloquently against
it.  Carl's argument is probably much more solid than mine,
but just for the record, what do you think?

>> For between-title-spacing however, I should mention that
>> if the upper attachment point (of 'space and
>> 'minimum-distance) is moved to the bottom of the upper
>> markup, then the 'padding value is basically rendered
>> redundant.
>
> This is not actually true (even if we change the refpoint
> to the bottom) because minimum-distance measures the
> distance from the refpoint of the markup to the *refpoint*
> of the next system, while padding measures the distance to
> the *top* of the next system.

Now I see my error, thanks.

>> Personally, I think we should add a new variable to
>> control the spacing between a markup and the bottom
>> margin.  We could call it bottom-markup-spacing for now,
>> but see this post for my proposed variable renaming:
>
> This is easy enough to add (and the naming seems fine to
> me).

Carl, are you opposed to bottom-markup-spacing (or
"markup-bottom-spacing" in the new naming system) for any
reason?

* * * * * * * * * *

Alexander Kobel wrote:
> I regularly use 'minimum-distance and a large negative
> 'padding in bottom-system-spacing to align the last staves
> to the same Y-offset, regardless of single note descenders
> or similar.
>
> Also, this is a case where I actually wish the "reference
> point" of the markup were on the opposite side, i.e. the
> bottom of the markup (or top of the bottom margin), s.t.
> any copyright or tagline really stays inside the footer
> and does not destroy the alignment of the staves on the
> page.  That'd amount to introducing a new
> last-staff-to-bottom-margin-spacing and leaving
> bottom-system-spacing as is, or - functionally equivalent,
> but somehow irritatingly - shifting the attachment point
> of bottom-system-spacing to the bottom of the markup and
> adding last-staff-to-top-of-markup-spacing.
>
> @ Mark: is the latter what you meant with your idea from
> above?

No, I don't think so, my idea was not so sophisticated.
What I meant with bottom-markup-spacing was to split the
current action of bottom-system-spacing into two variables,
one to control the spacing above the bottom-margin when a
system is the lowest printed item, and one to control the
spacing above the bottom-margin when a markup is the lowest
printed item.

That being said, your more intricate suggestions are
definitely interesting, and while I'm probably a little too
tired to comment on them right now, I hope the others share
their thoughts on them.  However, this reminds me of yet
another issue (and IMO a significant one) that I keep
forgetting to mention:

I've noticed that in many traditionally-engraved scores, the
distance from the bookTitleMarkup baseline to the first
system seems to be *independent* of the distance from the
scoreTitleMarkup baseline to the first system.

For example, say score1 has title/subtitle/etc. in the usual
place (top center), and piece/opus also in the usual place
(flush left and flush right just above the top system), and
the top system has no protruding skyline.  Now score2 has
all the same titling but the top system has a really high
note just before the rightmost barline.

To prevent a collision between the last note and the opus,
LilyPond will shift the first system down.  Fine.  But what
I've noticed in the classic scores is that in this
situation, the top system is not shifted down, but rather
the opus is shifted *up*.  This is an important difference!

It means that the placement of the top system is determined
by the bookTitleMarkup, and the scoreTitleMarkup is
determined by the top system.  And it usually looks better
this way (and more consistent from score to score).  I guess
I wouldn't be surprised if Joe says that this would be more
trouble than it's worth*, since it seems to go against the
whole pattern of the current spacing algorithm, but I think
it would be a big step towards fully professional-quality
scores.

*and if he says it would be easy, well that would just make
my day...

Joe?

* * * * * * * * * *

Trevor Daniels wrote:
> Further to my suggestion to leave the renaming to GLISS,
> so far there have been only comments supporting the
> renaming, even from Joe.  Since no discussion seems to be
> necessary, do you think it might be better to change the
> names before 2.14?  That way users would only have to
> understand one change in the stable releases rather than
> two.

Definitely.

- Mark