Re: Uses single algorithm for side-position spacing. (issue 6827072)

[mike]

On 30 nov. 2012, at 07:25, address@hidden wrote:

'finger-chords.ly' is still in disagreement with its texidoc (therefore
failing).  You could adjust that regtest in light of the new defaults,
of course.

Better might be to make Fingering.add-stem-support = #only-if-beamed
the new default.  That is in better agreement with common practice.
Regtests come out just as good.  (Les-neréides.ly can remove a couple
"tweaks", which seems to be how somebody was keeping score.)  Then users
will less often want to override add-stem-support, and when they do it
will be to the simpler ##f or ##t

The while(dirty) loop runs 2366 times for the last chord in
'fingering-collision.ly' but that's an extreme case.

I'm not proud of this...

It is at least comprehensible; while the code it replaced was utterly
baffling.  I simplified the loop
<http://codereview.appspot.com/6854121/>

I'm OK w/ the simplification, but I'd like it in box-quarantine if possible.  I'd like to separate the shifting algorithm from the class.  This is part of an effort, in general, to simplify and clarify the distinction between positioning algorithms and classes that use these algorithms (this is what I was doing w/ interval-minefield.cc as well).  Eventually, box-quarantine will be used for the ScriptColumn grob.

You should at least put the filenames back to what they were, and adjust
any tests or documentation or snippets using add-stem support, before
pushing.

I started to test with real music.  The usual Chopin test case
<http://www.mutopiaproject.org/cgibin/piece-info.cgi?id=1776>
has a badly broken cross-staff beam in measure 27.  I don't yet see the
cause.

Ugh...this is a really nasty cyclic dependency.  In the old algorithm, when Y side positioning was done, X extents weren't necessary because we just assumed that things had infinite X extents.  Now with the skylines, both X and Y extents are necessary to build the skylines.  The cyclic dependency is with beam directions.  The triggering chain is something to the effect of:

1) note_head_x_shift

2) stem direction

3) beam direction

4) pure y coordinates of stems to figure out auto knees

5) pure internal minimum translations via align interface

6) lots of pure heights in the axis group interface

7) pure heights of fingerings depend on new skyline side positioning algorithm

8) this algorithm needs the width of a note_head whose stem is attached to the same beam in (3) above, so note_head_x_shift

9) stem direction of the stem attached to that note

10) beam direction

The dependency seems breakable, but it'll require some mental gymnastics to figure out how.  I'm on it.

Cheers,
MS