Re: Ties colliding in single-staff polyphony

[address@hidden]

On Jul 18, 2011, at 10:14 AM, Bertrand Bordage wrote:

> Hi all,
> 
> A bug I noticed years ago :
> 
> <<
>  { a'4~ a' a'~ a' <f' a'>~ <f' a'> } \\
>  { c' c' c' c' } \\
>  { f'~ f' \shiftOff f'~ f' } \\
>>> 
> 
> Ties should take noteheads from other contexts into account.
> 
> Regards,
> Bertrand

I'm loath to write another collision engraver, but one solution to this problem 
would be to create a tie collision engraver that works just like the beam 
collision engraver.  Harvest all grobs from other voices that could potentially 
intersect in this engraver and throw them into a collision-grobs Grob_array.  
Then, in Tie_formatting_problem::score_ties, call a new function 
score_ties_collision that itself calls score_tie_collision.  In 
score_tie_collision, add a demerit for ties that collide with offending grobs.

Cheers,
MS