railtracks/caesura

[Han-Wen Nienhuys]

address@hidden writes:
> Why do I ask?  Well, I am going to revamp breathing-sign.cc anyway in
> order to add another couple of breathing signs for gregorian chant
> notation.  Some of them are centered on the staff (and their size depends
> on the staff height, much like bar symbols); therefore I have to do
> something with Breathing_sign::offset_callback (SCM element_smob, SCM).
> 
> Solution 1: offset_callback always returns 0 (or is removed at all);
> instead, brew_molecule cares for the offset (drawback: I am infiltrating
> the ordinary way to handle offsets).
> 
> Solution 2: offset_callback must peek into the grob property "text" to
> decide if this is a centered-on-staff breathing sign or not (drawback:
> sounds like bad style to peek into a "text" property to compute the
> offset, and much code of brew_molcule (if-then-else on "text" property;
> staff height evaluation) will be duplicated in offset_callback).
> 
> Solution 3: introduce a "centered-on-staff" grob property that is set in
> brew_molecule and read in offset_callback (drawback: yet another
> grob property just for transfering a single bit of information from
> brew_molecule to offset_callback and staff height stuff still duplicated).

the offset callback is to support setting directions on breathing
signs. I suppose that gregorian breathing are never used in a
polyphonic context, the point is moot. I would code the support for
gregorian signs in a separate Breathing_sign::gregorian , and override
#'Y-offset-callbacks for the Gregorian case. I prefer it if gregorian
formatting is kept separate from the normal case (unless there is a
significant amount of code shared.)

> What do you prefer?
> 
> In any case, I do not see any reason for keeping
> SCM Breathing_sign::railtracks, or do I miss something?

I still am not sure about the proper formatting of the // . The SCM
version is potentially more tweakable, but I prefer the layout of the
feta version. AFAIC, the  SCM version can go.

-- 

Han-Wen Nienhuys   |   address@hidden   |   http://www.cs.uu.nl/~hanwen