From b75db784e3d6a9e1d2cff3f77036aaa88598b53c Mon Sep 17 00:00:00 2001
From: Han-Wen Nienhuys <hanwen@lilypond.org>
Date: Tue, 7 Nov 2006 16:43:12 +0100
Subject: [PATCH] Examine Stem::duration_log() for preventing merge of quarter
 and half note. Fixes collision-heads.ly. Add separate regtest for that.

---
 .../collision-merge-differently-headed.ly          | 25 ++++++++++++++++++++++
 lily/note-collision.cc                             | 13 ++++++-----
 2 files changed, 33 insertions(+), 5 deletions(-)
 create mode 100644 input/regression/collision-merge-differently-headed.ly

diff --git a/input/regression/collision-merge-differently-headed.ly b/input/regression/collision-merge-differently-headed.ly
new file mode 100644
index 0000000000..62e6e6b7a8
--- /dev/null
+++ b/input/regression/collision-merge-differently-headed.ly
@@ -0,0 +1,25 @@
+\version "2.7.39"
+\header {
+  texidoc =
+
+  "If @code{merge-differently-headed} is enabled, then
+open note heads may be merged with black noteheads, but only
+if the black note heads are from 8th or shorter notes.
+"
+  
+}
+
+\layout { ragged-right= ##t }
+
+
+\context Staff  \relative c'' <<
+  {
+    \override Staff.NoteCollision  #'merge-differently-headed = ##t
+    c2 c8 c4.
+    c2
+  }\\
+  {
+    c8 c4. c2
+    c4
+  }
+>>
diff --git a/lily/note-collision.cc b/lily/note-collision.cc
index bce6d08a60..ddfbf19983 100644
--- a/lily/note-collision.cc
+++ b/lily/note-collision.cc
@@ -39,6 +39,9 @@ check_meshing_chords (Grob *me,
   if (!Note_column::get_stem (cu) || !Note_column::get_stem (cd))
     return;
 
+  Drul_array<Grob*> stems (Note_column::get_stem (cd),
+			   Note_column::get_stem (cu));
+  
   Grob *nu = Note_column::first_head (cu);
   Grob *nd = Note_column::first_head (cd);
 
@@ -90,10 +93,10 @@ check_meshing_chords (Grob *me,
   /* Should never merge quarter and half notes, as this would make
      them indistinguishable.  */
   if (merge_possible
-      && ((Rhythmic_head::duration_log (nu) == 1
-	   && Rhythmic_head::duration_log (nd) == 2)
-	  || (Rhythmic_head::duration_log (nu) == 2
-	      && Rhythmic_head::duration_log (nd) == 1)))
+      && ((Stem::duration_log (stems[UP]) == 1
+	   && Stem::duration_log (stems[DOWN]) == 2)
+	  || (Stem::duration_log (stems[UP]) == 2
+	      && Stem::duration_log (stems[DOWN]) == 1)))
     merge_possible = false;
 
   /*
@@ -535,4 +538,4 @@ ADD_INTERFACE (Note_collision_interface, "note-collision-interface",
 	       /* properties */
 	       "merge-differently-dotted "
 	       "merge-differently-headed "
-	       "positioning-done");
+	       "positioning-done ");
-- 
2.11.4.GIT