Re: [Lilypond-auto] Issue 185 in lilypond: RhythmicStaff squishing chords should produce single notes

[lilypond]

Comment #3 on issue 185 by address@hidden: RhythmicStaff squishing  
chords should produce single notes
http://code.google.com/p/lilypond/issues/detail?id=185#c3

Make RhythmicStaff show single notes for chords (issue 185)

RhythmicStaff uses Pitch_squash_engraver to move all note heads to a
common vertical position. With chords, at least two problems arise:

(1) As all notes from one chord collide now, so some of them used to
    be moved aside. Hence, for each chord, two adjacent note heads
    would appear in the output.

(2) For chords with dotted duration, Dot_column_engraver would put one
    dot per note head into a DotColumn, where they would be spaced
    apart. So for every note in the chord, one separate dot would be
    visible.

Solve (1) by explicitly setting X-offset to 0 for squashed note heads
in the Pitch_squash_engraver.

Solve (2) by replacing Dot_column_engraver with a new
Squashed_dot_column_engraver. This variant puts only at most one dot
per time step onto a DotColumn, and marks any further ones as
transparent.

Update regression test rhythmic-staff.ly to include two chords.

http://codereview.appspot.com/6495107