X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;ds=sidebyside;f=lily%2Fbeam-concave.cc;h=501b753d2108a1f858f75663865e7f03fcb67ba5;hb=b29bb82ddbf82b9989fa1f1e552491a2f6e5504a;hp=ee351d0a26739d2fba275b4615cd108b3bfad33b;hpb=d8082113a0df616e7beabc0417c3590a3fac7320;p=lilypond.git

diff --git a/lily/beam-concave.cc b/lily/beam-concave.cc
index ee351d0a26..501b753d21 100644
--- a/lily/beam-concave.cc
+++ b/lily/beam-concave.cc
@@ -1,5 +1,34 @@
+/*
+  This file is part of LilyPond, the GNU music typesetter.
+
+  Copyright (C) 2004 Han-Wen Nienhuys <hanwen@lilypond.org>
+
+  LilyPond is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  LilyPond is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
 /*
   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"
@@ -23,7 +52,7 @@ is_concave_single_notes (vector<int> const &positions, Direction beam_dir)
   /*
     notes above and below the interval covered by 1st and last note.
   */
-  for (vsize i = 1; i < positions.size () - 1; i++)
+  for (vsize i = 1; i + 1 < positions.size (); i++)
     {
       above = above || (positions[i] > covering[UP]);
       below = below || (positions[i] < covering[DOWN]);
@@ -36,20 +65,20 @@ is_concave_single_notes (vector<int> const &positions, Direction beam_dir)
   */
   int dy = positions.back () - positions[0];
   int closest = max (beam_dir * positions.back (), beam_dir * positions[0]);
-  for (vsize i = 2; !concave && i < positions.size () - 1; i++)
+  for (vsize i = 2; !concave && i + 1 < positions.size (); i++)
     {
       int inner_dy = positions[i] - positions[i - 1];
       if (sign (inner_dy) != sign (dy)
-	  && (beam_dir * positions[i] >= closest
-	      || beam_dir * positions[i - 1] >= closest))
-	concave = true;
+          && (beam_dir * positions[i] >= closest
+              || beam_dir * positions[i - 1] >= closest))
+        concave = true;
     }
 
   bool all_closer = true;
-  for (vsize i = 1; all_closer && i < positions.size () - 1; i++)
+  for (vsize i = 1; all_closer && i + 1 < positions.size (); i++)
     {
       all_closer = all_closer
-	&& (beam_dir * positions[i] > closest);
+                   && (beam_dir * positions[i] > closest);
     }
 
   concave = concave || all_closer;
@@ -62,7 +91,7 @@ calc_positions_concaveness (vector<int> const &positions, Direction beam_dir)
   Real dy = positions.back () - positions[0];
   Real slope = dy / Real (positions.size () - 1);
   Real concaveness = 0.0;
-  for (vsize i = 1; i < positions.size () - 1; i++)
+  for (vsize i = 1; i + 1 < positions.size (); i++)
     {
       Real line_y = slope * i + positions[0];
 
@@ -80,14 +109,13 @@ calc_positions_concaveness (vector<int> const &positions, Direction beam_dir)
   return concaveness;
 }
 
-
 MAKE_SCHEME_CALLBACK (Beam, calc_concaveness, 1);
 SCM
 Beam::calc_concaveness (SCM smob)
 {
   Grob *me = unsmob_grob (smob);
 
-  vector<Grob*> stems
+  vector<Grob *> stems
     = extract_grob_array (me, "stems");
 
   if (is_knee (me))
@@ -96,29 +124,28 @@ Beam::calc_concaveness (SCM smob)
   Direction beam_dir = CENTER;
   for (vsize i = stems.size (); i--;)
     {
-      if (Stem::is_invisible (stems[i]))
-	stems.erase (stems.begin () + i);
+      if (Stem::is_normal_stem (stems[i]))
+        {
+          if (Direction dir = get_grob_direction (stems[i]))
+            beam_dir = dir;
+        }
       else
-	{
-	  if (Direction dir = get_grob_direction (stems[i]))
-	    beam_dir = dir;
-	}
+        stems.erase (stems.begin () + i);
     }
 
   if (stems.size () <= 2)
-    return SCM_UNSPECIFIED;
+    return scm_from_int (0);
 
   vector<int> close_positions;
   vector<int> far_positions;
   for (vsize i = 0; i < stems.size (); i++)
     {
       /*
-	For chords, we take the note head that is closest to 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.
+        For chords, we take the note head that is closest to 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]);
 
@@ -128,18 +155,16 @@ Beam::calc_concaveness (SCM smob)
 
   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;
     }
   else
     {
       concaveness = (calc_positions_concaveness (far_positions, beam_dir)
-		     + calc_positions_concaveness (close_positions, beam_dir)) / 2;
+                     + calc_positions_concaveness (close_positions, beam_dir)) / 2;
     }
 
   return scm_from_double (concaveness);
 }
 
-
-