Re: Uses single algorithm for side-position spacing. (issue 6827072)

[address@hidden]

On 18 nov. 2012, at 21:06, Keith OHara <address@hidden> wrote:

>>> 
>> 
>> Try running beam-cross-staff-script.ly with my patch and setting 
>> NoteColumn.cross-staff to ##f.  You'll see that it triggers beam slope 
>> calculations before vertical spacing is done on the staves because 
>> NoteColumn, which is a support for the script, has its height checked 
>> prematurely.  This does not happen in current master because NoteColumn is 
>> not a support for Scripts.
>> 
>> So why did I make NoteColumn a support for Scripts?  I use the NoteColumn as 
>> a side support object because it combines the width of the note head with 
>> the height of the stem.  We don't want UP staccatos, for example, getting 
>> tucked down to the left of UP stems but they will if skylines are used.  So, 
>> we use the NoteColumn as the side support.
>> 
> 
> I suppose that, strictly speaking, NoteColumn can be 'cross-staff=#t, meaning 
> "beware; I might move or change shape when staves are spread across the 
> page."  But, it seems to preserve more information if we can leave the 
> 'cross-staff indication specifically on the Stem.
> 
> Scripts clearing Stems is already a special case, controlled by 
> 'add-stem-support, which has in the past meant "keep this Script clear of the 
> end of the Stem and Flag of its parent, even if it could slide alongside."  
> Maybe 'add-stem-support could be implemented as "Consider the Script widened 
> enough to include a point on the extended line of the Stem, and keep the 
> widened Script clear of the Stem."
> 

I'm picking up what you're putting down...
What'd be easy is to add something to the effect of :

if (to_boolean (me->get_property ("add-stem-support"))
   && Stem::has_interface (e))
 skyline.set_min_height (e->extent (common_y, _Y_AXIS)[dir]);

That's pseudo-code, but do you get the idea?  Does that seem reasonable?  If 
so, I can get rid of all of that note column business in the engravers and then 
note column would no longer have to be cross staff.

Cheers,
MS