Use upper (beam direction independent) line for per-note concaveness

check. Fixes beam in the rachmaninov example.

diff --git a/input/regression/beam-concave-chord.ly b/input/regression/beam-concave-chord.ly
new file mode 100644 (file)
index 0000000..819dce8
--- /dev/null
+++ b/input/regression/beam-concave-chord.ly
@@ -0,0 +1,55 @@
+\version "2.11.40"
+
+
+morgenliedBeam = \relative c'' \new Voice{
+  \time 3/8
+  % morgenlied
+  c16 b c e g <e b'> |
+  \stemUp
+  c16 b c e g <e b'> |
+}
+
+rachmaninovBeams = \relative \new Voice {
+  \voiceOne
+  \time 4/4
+  \key c \minor
+  <c' e c'>8 <g c g'> <c f> <ees, ees'>~ <ees ees'> <c c'> <des des'> <d d'>
+}
+
+horizontalBeams = {
+  % todo.
+}
+
+nonHorizontalBeams = {
+  \morgenliedBeam
+  \rachmaninovBeams
+}
+\layout {
+  ragged-right = ##t
+  }
+
+% cut & paste from beam-concave.ly
+
+#(define (<> x y) (not (= x  y)))
+mustBeHorizontal = 
+  \override Staff.Beam #'positions = #(ly:make-simple-closure
+                                (ly:make-simple-closure
+                                 (append
+                                  (list chain-grob-member-functions `(,cons 0 0))
+                                  (check-slope-callbacks =))))
+mustNotBeHorizontal = 
+  \override Staff.Beam #'positions = #(ly:make-simple-closure
+                                (ly:make-simple-closure
+                                 (append
+                                  (list chain-grob-member-functions `(,cons 0 0))
+                                  (check-slope-callbacks <>))))
+
+
+\new Voice {
+  \mustBeHorizontal
+  r1
+  \horizontalBeams
+  \mustNotBeHorizontal
+  \nonHorizontalBeams
+}
+

diff --git a/lily/beam-concave.cc b/lily/beam-concave.cc
index e703f9e9f796c62a837fe36843584c32fe70c461..48d45c859945eaa87ded018191bb9ab421b7b640 100644 (file)
--- a/lily/beam-concave.cc
+++ b/lily/beam-concave.cc
@@ -1,5 +1,24 @@
+/* 
+  beam-concave.cc -- implement Concaveness for beams.
+  
+  source file of the GNU LilyPond music typesetter
+  
+  (c) 2004 Han-Wen Nienhuys <hanwen@lilypond.org>
+  
+*/
+

 /*
   Determine whether a beam is concave.
 /*
   Determine whether a beam is concave.

+
+  A beam is concave when the middle notes get closer to the
+  beam than the left and right edge notes.
+
+  This is determined in two ways: by looking at the positions of the
+  middle notes, or by looking at the deviation of the inside notes
+  compared to the line connecting first and last.
+
+  The tricky thing is what to do with beams with chords. There are no
+  real guidelines in this case.

 */
 
 #include "pointer-group-interface.hh"
 */
 
 #include "pointer-group-interface.hh"


@@ -118,7 +137,6 @@ Beam::calc_concaveness (SCM smob)
        Hmmm.. wait, for the beams in the last measure of morgenlied,
        this doesn't look so good. Let's try the heads farthest from
        the beam.
        Hmmm.. wait, for the beams in the last measure of morgenlied,
        this doesn't look so good. Let's try the heads farthest from
        the beam.

-

       */
       Interval posns = Stem::head_positions (stems[i]);
 
       */
       Interval posns = Stem::head_positions (stems[i]);
 


@@ -128,7 +146,7 @@ Beam::calc_concaveness (SCM smob)
 
   Real concaveness = 0.0;
 
 
   Real concaveness = 0.0;
 

-  if (is_concave_single_notes (far_positions, beam_dir))
+  if (is_concave_single_notes (beam_dir == UP ? close_positions : far_positions, beam_dir))

     {
       concaveness = 10000;
     }
     {
       concaveness = 10000;
     }