cleanup alignments of various grobs

SUMMARY: DynamicTexts, TextScripts and many other grobs use aligned_on_parent, which makes their behaviour consitent, predictable and thus more user-friendly.


Consists of 3 commits:


Clean up DynamicText horizontal alignment.

Until now, DynamicText alignment was messy, as there were 3 different
callbacks involved - some of them interacting in a confusing way:
    - in define-grobs.scm, X-offset property was initialized to
    ly:self-alignment-interface::x-aligned-on-self,
    - Dynamic_engraver called set_center_parent on every DynamicText
    attached to a note, so that half a NoteHead width was always added
    to its X-offset (producing confusing results for example when
    user requested dynamics to be left-aligned),
    - DynamicTexts living in a Dynamics context used a completely
    different offset callback, which aligned them on NoteColumns.

Since aligned_on_parent is now able to correctly align grobs
with PaperColumn parents (issue 3254), we can use it for all
DynamicTexts and have a single interface for the job.

Expected changes in output: DynamicTexts in Dynamics context
aligned to suspended noteheads may be placed up to 1/4 NoteHead
width further to the right.  This shouldn't be a problem.


Replace XY-offset closures with aligned_on_parent where possible

It doesn't make sense to specify placement using multiple added
callbacks or closures when we can use aligned_on_parent. What's
more, aligned_on_parent should expose more consistent interface
for the users - affected grobs should now behave similarly to
LyricTexts and DynamicTexts. For example, this

\relative c'' \context Voice {
    \compressFullBarRests
    \override MultiMeasureRestNumber.self-alignment-X = #RIGHT
    R1*100
}

will result in right edge of the MultiMeasureRestNumber being
aligned on the right edge of the MultiMeasureRest.

Affected grobs:
- Fingering
- AccidentalSuggestion
- ClefModifier
- DoublePercentRepeatCounter
- GridLine
- MultiMeasureRestNumber
- MultiMeasureRestText
- PercentRepeatCounter
- StemTremolo

Expected changes in output: none.


TextScript, CombineTextScript: use aligned_on_parent

I think this makes more sense than just using "self-alignment".
It makes these grobs consistent with Lyrics and Dynamics, and
allows users to override their alignment more predictably.

Expected changes in output: TextScripts and CombineTextScripts 
will be aligned slightly different when the user sets self-alignment-X
explicitly (parent notehead will be included in alignment, as in Lyrics).
Default placement should remain the same.

I'm also changing one regtest, just to make sure that despite slightly
changed alignment the markups will stick out far enough to the left.

[janek, 2014-06-26 18:37:12]

Hello,

this is a follow-up to issues 3254
(https://code.google.com/p/lilypond/issues/detail?id=3254) and 3962
(https://code.google.com/p/lilypond/issues/detail?id=3962).  It's not finished
yet, but you should get an idea of where i'm heading with
self-alignment-interface.  Comments welcome!

thanks,
Janek

[lemzwerg, 2014-06-27 04:34:36]

LGTM (without any testing).

[janek, 2014-06-28 12:36:45]

rebase on master, don't include aligned_on_parent refactoring

[janek, 2014-06-28 21:57:53]

keep old value for TextScript alignment (fix fingering diagrams)

[janek, 2014-06-28 22:37:05]

On 2014/06/27 04:34:36, lemzwerg wrote:
> LGTM (without any testing).

Thanks, Werner!

I decided to move code refactoring to another issue, so that this one is only
about changing how various grobs are aligned.  It is now Issue 3978
(https://code.google.com/p/lilypond/issues/detail?id=3978), and the refactoring
will be done in issue 3979.

I apologize for confusion!
Janek

[janek, 2014-06-29 23:07:54]

rebase on master, slightly adjust one regtest

[janek, 2014-07-04 20:48:04]

whitespace fixes and property reordering (shouldn't affect countdown)

[janek, 2014-07-05 21:16:17]

Pushed as merge commit:

*   0bc7f77 Issue 3978: Merge alignment cleanup
|\  
| * d6604b0 define-grobs.scm: reorder properties
| * 6f3f8f0 TextScript: use aligned_on_parent
| * 1d76502 Replace offset closures with aligned_on_parent
| * 09412c2 Clean up DynamicText horizontal alignment.
|/