Re: thoughts on changing \magnifyMusic, please comment

[Janek Warchoł]

2014-08-02 9:05 GMT+02:00 Mark Polesky <address@hidden>:
> Janek Warchoł wrote:
>> So, we can say that \magnifyStaff sets staff "size" to an
>> absolute value - defined as the fraction of the default
>> size - and not "relative" to the previous size.
>
> Not exactly.  A magnifyStaff value is only relative to the
> previous staff size the first time it's used in a given
> staff.  The value of "1" refers to the settings that are in
> effect when magnifyStaff is first called.  After that, then
> yes, I suppose it's "absolute".  But it's not precise to say
> that it scales the "default" values, since it scales the
> user's settings.

Ok, i see.

>>> Subsequent calls to \magnifyStaff will first revert the
>>> most recent layer of temporary overrides, but only if
>>> the magnification value is different from last time.
>>
>> - do i understand correctly that this means that
>> \magnifyStaff is aware of the previous magnification value
>> used?
>
> Yes.  I've added a new Staff context property
> `magnifyStaffValue' to store that.

What about naming it 'staffSize'?

>> If so, would it be possible to make a "relative" version
>> of \magnifyStaff, similarly to how we have relative and
>> absolute markup commands (\large and \larger)?  I think
>> this could be useful.
>
> Hmm, sometimes I wonder if we're not wandering into levels
> of esoterica here.  At a minimum, we should provide the user
> an easy way to do these two things:
>   1) ossia staves
>   2) small staves for non-piano instruments
>      in chamber music scores with piano
>
> This is now available; just throw magnifyStaff in a \with
> block and you're done.

Yes, that's indeed the basic use-case and it's handled nicely.

> Then, to my great surprise, someone
> requested the ability to change staff size mid-stream in a
> Staff context:
>   http://lists.gnu.org/archive/html/lilypond-user/2014-06/msg00400.html
>
> So I made sure that magnifyStaff could do that:
>   ...
>   \magnifyStaff 0.75
>   ...
>   \magnifyStaff 1    % revert back to initial size
>   ...
>
> Now with requests for absolute and relative versions, as
> well as this:
>
>   \temporary \magnifyStaff 1.3
>   ...
>   \undo \magnifyStaff 1.3
>
> ...I'm starting to wonder how much of this is really
> necessary.  Can anyone provide an actual use case to justify
> accommodating either of these requests?

I admit that i don't have an actual use case.  I expect that crazy
composers like Mike (hello Mike! :)) could want to make the staff
progressively bigger and bigger each measure, for example as a fancy
way of indicating global crescendo sustained over many measures.  But
that's just a speculation.

> Also, to be honest, I don't really like the idea of the
> \larger command, since it feels so arbitrary.  I could do:
>    \largerStaff
>    \smallerStaff
>
> but I'm not wild about that idea.  I suppose I could also
> figure out a way to do:
>    \magnifyStaffAbsolute
>    \magnifyStaffRelative
>
> but that still seems silly to me.

I don't think we have to provide mechanisms for both relative and
absolute staff scaling right now.  I just think that it's good to
design the functionality (and name the functions) with such
possibility in mind.

> One thought I had was
> putting the burden of reverting on the user, when wanting to
> change from one non-default size to another, something like
> this:
>    ...                % size 1
>    \magnifyStaff 0.75 % size 0.75
>    ...
>    \resetStaffSize    % size 1
>    \magnifyStaff 2    % size 2
>    ...
>
> Then if one really wanted a "relative" magnifyStaff, they
> could do:
>    ...                % size 1
>    \magnifyStaff 0.75 % size 0.75
>    ...
>    \magnifyStaff 2    % size 1.5
>    ...
>
> But do you really think this is what users are going to
> want?

I agree that this wouldn't be most intuitive.  I think that the way
\magnifyStaff works now is very good.  Changing staff size relatively
would have to be another function, if we ever decide to support it.

> I think I'm
> leaning towards:
>   1) keeping magnifyStaff as it is
>   2) making magnifyMusic syntax like magnifyStaff
>   3) changing magnifyMusic to magnifyVoice

+1

best,
Janek