Doc-es: various updates.

[lilypond.git] / lily / beaming-pattern.cc

diff --git a/lily/beaming-pattern.cc b/lily/beaming-pattern.cc
index 4415debf98677e04888299dde09e760479b57245..46a46a5d2ea529aa4c1e09836413f4ee0b708d05 100644 (file)
--- a/lily/beaming-pattern.cc
+++ b/lily/beaming-pattern.cc
@@ -1,7 +1,7 @@
 /*
   This file is part of LilyPond, the GNU music typesetter.
 
-  Copyright (C) 1999--2014 Han-Wen Nienhuys <hanwen@xs4all.nl>
+  Copyright (C) 1999--2015 Han-Wen Nienhuys <hanwen@xs4all.nl>
 
   LilyPond is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -19,6 +19,7 @@
 
 #include "context.hh"
 #include "beaming-pattern.hh"
+#include "misc.hh"
 
 /*
   Represents a stem belonging to a beam. Sometimes (for example, if the stem
@@ -162,14 +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_)
-                        ? 1 : 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;
           }
@@ -359,6 +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
 {