Re: Gets the beam collision engraver to handle autobeams (issue4287061)

[address@hidden]

On Mar 22, 2011, at 7:22 PM, address@hidden wrote:

> On 2011/03/20 12:00:34, MikeSol wrote:
>> This is now fully functional.
>> The only issue is that, for auto-beams, I don't have a good method yet
> for
>> keeping note-heads that are part of the beam out of the covered grobs
> list.
>> This is doable, though - I just have to think of the cleanest way.
> 
> Before you attempt that, can you think of a cleaner way to implement the
> basic functionality which doesn't involve creating a dummy grob?
> 
> Cheers,
> Neil

OK, idea:

In the auto beam engraver, every time a beam is created, a variable called 
timestep_ticker_ gets reset to 0 and increments by +1 for every timestep passed 
until the beam is completed (or junked if the beam is junked).  This is stashed 
as an internal property called "timesteps-spanned."

Then, in the beam collision engraver, there is a vector<vector<Grob *> *> 
called covered_grobs_queue_ that stores vectors of all acknowledged grobs 
(clefs, note-heads, accidentals, etc.) for a given timestep (with an empty 
vector being assigned for a acknowledged-grobless timestep).  This vector is 
cleared at every barline (w/ appropriate deletes for the pointers to vectors).  
When an autobeam is completed (which we'll know because it will be announced 
during the same timestep as its end-grob), we look at the property 
timesteps-spanned and iterate through covered_grobs_queue_ starting from 
covered_grobs_queue_.size () - timesteps_spanned to the end, adding its 
contents to the grob array covered-grobs.

Does this seem like a good idea?  It'd need some tweaking to deal w/ covered 
interior grobs & to avoid code dups, but I think it's clean.

Cheers,
Mike