Re: Fixing bugs #379 and #427

[Patrick McCarty]

On 2009-08-14, Han-Wen Nienhuys wrote:
> On Thu, Aug 13, 2009 at 8:03 PM, Patrick McCarty <address@hidden> wrote:
> >
> > See the attached patch for the progress I've made.  Also attached is
> > an image of Mark Polesky's example from the bug tracker:
> >
> > http://code.google.com/p/lilypond/issues/detail?id=379#c4
> >
> > Note that I have not run the regression test suite, so I do not yet
> > know the impact this patch has overall.
> 
> 
> This is a nice try, but it is the wrong approach.  The problem is that
> the currentCommandColumn will include all ittems from all staves.  If
> there is a clef-change on a different staff, this will shorten all
> broken slurs.
> 
> For the correct approach, the slur needs to figure what objects there
> at the end and start of the current line break.  I guess the easiest
> approach is to acknowledge breakable SeparationItems in the engraver,
> and modify the slur formatting code (where it currently calls
> breakable_bound_item), to check for a separation item that lies on the
> same column as slur->get_bound().  If you find an object like that,
> you can extract the leftmost or rightmost item, and use that for
> adjusting the bounds.

Thanks for the suggestions, Han-Wen.

However, SeparationItem grobs are not created anymore, and the only
other grobs belonging to the separation-item-interface are
NonMusicalPaperColumn, NoteColumn, and PaperColumn.

Is there another strategy I can use to find items bound to columns at
slur->get_bound() that are *only* found in the same staff as Slur or
PhrasingSlur?

Should I check for common Y refpoints between a Slur and Clef in a
different staff to filter these out?  Or different Y parents?  I made
a cursory attempt at doing this, but I wasn't sure how to accomplish
it.


Thanks again,
-Patrick