don't abort aligning when grob's parent is a PaperColumn

If a grob's parent is a PaperColumn, align using NoteColumns extent.

This makes unassociated lyrics behave consistently with associated lyrics.

Until now, unassociated lyrics (i.e. lyrics without an associatedVoice) were all left-aligned (more precisely: their X-offset was 0).  Changing self-alignment-X didn't have any effect on them.  This was because X-parent of an unassociated LyricText is a PaperColumn, and aligned_on_parent didn't know how to handle that.

This patch tells aligned_on_parent to use the extent of respective NoteColumns as the parent extent needed for grob alignment.  Additionally to fixing unassociated lyrics behaviour, this should allow correctly aligning_on_parent other grobs, such as DynamicTexts.

Expected changes in regtests: all lyrics should now be centered by default.  This affects 11 regtests.

[janek, 2013-03-17 23:58:50]

Please review.
You'll find a sample test file in tracker issue:
http://code.google.com/p/lilypond/issues/detail?id=3254

[Trevor Daniels, 2013-03-18 10:36:35]

I can't easily test this, but on the basis of the
reg tests - LGTM

[janek, 2013-03-18 13:05:15]

On 2013/03/18 10:36:35, Trevor Daniels wrote:
> I can't easily test this, but on the basis of the
> reg tests - LGTM

Do you mean that i should improve the test file which is attached to tracker
issue?

Janek

[Trevor Daniels, 2013-03-18 16:05:44]

On 2013/03/18 13:05:15, janek wrote:
> On 2013/03/18 10:36:35, Trevor Daniels wrote:
> > I can't easily test this, but on the basis of the
> > reg tests - LGTM
> 
> Do you mean that i should improve the test file which is attached to tracker
> issue?
> 
> Janek

No, the test file looks fine.  It's just that I'm not
in a position to compile LilyPond at the moment.

Trevor

[janek, 2013-03-18 23:59:20]

calculate extent of notecolumn and use it for aligning

[janek, 2013-03-19 00:36:11]

add regtest

[MikeSol, 2013-03-19 15:21:37]

https://codereview.appspot.com/7564044/diff/9001/lily/self-alignment-interfac...
File lily/self-alignment-interface.cc (right):

https://codereview.appspot.com/7564044/diff/9001/lily/self-alignment-interfac...
lily/self-alignment-interface.cc:130: // TODO: should this function be defined
someplace else, e.g. in note-column.cc?
I like where you're going with this.
I would recommend creating a function algined_on_grobs that accepts a grob, an
vector of grobs to align to, and an axis.  Then algined_on_parent becomes a
subset of this where the vector is of length one and is the parent.
Then, you can create a function
Self_alignment_interface::lyrics_algined_on_note_columns that invokes
aligned_on_grobs with a vector of note columns returned using the search method
in this function.  This function could be implemented in paper-column.cc as
get_generic_interface_extent such that it recurses through a paper columns'
element list, finds all grobs implementing interface X and returns them.

[janek, 2013-03-19 19:18:53]

Thanks for reviewing, Mike!  I'm uploading new patchset.

https://codereview.appspot.com/7564044/diff/9001/lily/self-alignment-interfac...
File lily/self-alignment-interface.cc (right):

https://codereview.appspot.com/7564044/diff/9001/lily/self-alignment-interfac...
lily/self-alignment-interface.cc:130: // TODO: should this function be defined
someplace else, e.g. in note-column.cc?
On 2013/03/19 15:21:37, MikeSol wrote:
> I like where you're going with this.
> I would recommend creating a function algined_on_grobs that accepts a grob, an
> vector of grobs to align to, and an axis.  Then algined_on_parent becomes a
> subset of this where the vector is of length one and is the parent.
> Then, you can create a function
> Self_alignment_interface::lyrics_algined_on_note_columns that invokes
> aligned_on_grobs with a vector of note columns returned using the search
method
> in this function.

I'll post a detailed answer in https://codereview.appspot.com/7768043/

> This function could be implemented in paper-column.cc as
> get_generic_interface_extent such that it recurses through
> a paper columns'element list, finds all grobs implementing
> interface X and returns them.

Good idea! Done.

[janek, 2013-03-19 19:19:09]

make the method for calculating extents more generic and move it to PaperColumn