X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=lily%2Fbeaming-pattern.cc;h=46a46a5d2ea529aa4c1e09836413f4ee0b708d05;hb=97a0169312a260933246ab224e4f8b0969871dd5;hp=cb8c91dbece9de761ba7a5d1421e4f5e8c12987c;hpb=0382ed88b53cb24e76a1935e18df32cc87174428;p=lilypond.git

diff --git a/lily/beaming-pattern.cc b/lily/beaming-pattern.cc
index cb8c91dbec..46a46a5d2e 100644
--- a/lily/beaming-pattern.cc
+++ b/lily/beaming-pattern.cc
@@ -132,8 +132,6 @@ Beaming_pattern::beamify (Beaming_options const &options)
   if (infos_.size () <= 1)
     return;
 
-  int subdivide_beam_count = intlog2(options.base_moment_.main_part_.den())-2;
-
   unbeam_invisible_stems ();
 
   if (infos_[0].start_moment_.grace_part_)
@@ -165,15 +163,27 @@ Beaming_pattern::beamify (Beaming_options const &options)
   for (int i = 0; i < 2; i++)
     for (vsize i = 1; i < infos_.size () - 1; i++)
       {
-        Direction non_flag_dir = other_dir (flag_directions[i]);
+        Direction non_flag_dir = -flag_directions[i];
         if (non_flag_dir)
           {
-            int importance = infos_[i + 1].rhythmic_importance_;
-            int count = (importance < 0 && options.subdivide_beams_) 
-                        ? subdivide_beam_count
-                        : min (min (infos_[i].count (non_flag_dir),
-                                        infos_[i + non_flag_dir].count (-non_flag_dir)),
-                                   infos_[i - non_flag_dir].count (non_flag_dir));
+            int count =
+                (infos_[i + 1].rhythmic_importance_ < 0 &&
+                 options.subdivide_beams_)
+                        // we're left of a subdivision
+                ?  (i != infos_.size () - 2)
+                   // respect the beam count for shortened beams ...
+                   ? max (beam_count_for_rhythmic_position (i + 1),
+                          beam_count_for_length (remaining_length (i + 1)))
+                   // ... except if there's only one trailing stem
+                   : beam_count_for_rhythmic_position (i + 1)
+
+                // we're at any other stem
+                : min (min (infos_[i].count (non_flag_dir),
+                            infos_[i + non_flag_dir].count (-non_flag_dir)),
+                       infos_[i - non_flag_dir].count (non_flag_dir));
+
+            // Ensure at least one beam is left, even for groups longer than 1/8
+            count = max (count, 1);
 
             infos_[i].beam_count_drul_[non_flag_dir] = count;
           }
@@ -363,6 +373,25 @@ Beaming_pattern::end_moment (int i) const
          + infos_.at (i).factor_ * dur.get_length ();
 }
 
+Moment
+Beaming_pattern::remaining_length (int i) const
+{
+    return end_moment (infos_.size () - 1) - infos_[i].start_moment_;
+}
+
+int
+Beaming_pattern::beam_count_for_rhythmic_position (int idx) const
+{
+    // Calculate number of beams representing the rhythmic position of given stem
+    return intlog2(infos_[idx].start_moment_.main_part_.den()) - 2;
+}
+
+int
+Beaming_pattern::beam_count_for_length (Moment len) const
+{
+    return intlog2(len.main_part_.den()) - 2 - intlog2(len.main_part_.num());
+}
+
 bool
 Beaming_pattern::invisibility (int i) const
 {