Issue 2945: Document symbol list changes.

[lilypond.git] / lily / stem.cc

diff --git a/lily/stem.cc b/lily/stem.cc
index 4b5a68510b2752cc43fe4a160e40add3d4673c0b..4d5b7746b59fcfc1e8292741b335c7fd46b4a470 100644 (file)
--- a/lily/stem.cc
+++ b/lily/stem.cc
@@ -275,9 +275,12 @@ Stem::add_head (Grob *me, Grob *n)
 bool
 Stem::is_invisible (Grob *me)
 {
-  return !is_normal_stem (me)
-         && (robust_scm2double (me->get_property ("stemlet-length"),
-                                0.0) == 0.0);
+  if (is_normal_stem (me))
+    return false;
+  else if (head_count (me))
+    return true;
+  else // if there are no note-heads, we might want stemlets
+    return 0.0 == robust_scm2double (me->get_property ("stemlet-length"), 0.0);
 }
 
 bool
@@ -545,7 +548,8 @@ Stem::calc_positioning_done (SCM smob)
           = hed->extent (hed, X_AXIS).linear_combination (CENTER)
             - heads[i]->extent (heads[i], X_AXIS).linear_combination (CENTER);
 
-      heads[i]->translate_axis (amount, X_AXIS);
+      if (!isnan (amount)) // empty heads can produce NaN
+        heads[i]->translate_axis (amount, X_AXIS);
     }
   bool parity = true;
   Real lastpos = Real (Staff_symbol_referencer::get_position (heads[0]));
@@ -689,7 +693,7 @@ Interval
 Stem::internal_height (Grob *me, bool calc_beam)
 {
   Grob *beam = get_beam (me);
-  if (!is_valid_stem (me) && ! beam)
+  if (!is_valid_stem (me) && !beam)
     return Interval ();
 
   Direction dir = get_grob_direction (me);
@@ -700,6 +704,13 @@ Stem::internal_height (Grob *me, bool calc_beam)
       (void) beam->get_property ("quantized-positions");
     }
 
+  /*
+    If there is a beam but no stem, slope calculations depend on this
+    routine to return where the stem end /would/ be.
+  */
+  if (calc_beam && !beam && !unsmob_stencil (me->get_property ("stencil")))
+    return Interval ();
+
   Real y1 = robust_scm2double ((calc_beam
                                 ? me->get_property ("stem-begin-position")
                                 : me->get_pure_property ("stem-begin-position", 0, INT_MAX)),
@@ -787,7 +798,8 @@ Stem::internal_calc_stem_begin_position (Grob *me, bool calc_beam)
       Real y_attach = Note_head::stem_attachment_coordinate (head, Y_AXIS);
 
       y_attach = head_height.linear_combination (y_attach);
-      pos += d * y_attach * 2 / ss;
+      if (!isinf (y_attach) && !isnan (y_attach)) // empty heads
+        pos += d * y_attach * 2 / ss;
     }
 
   return pos;
@@ -804,9 +816,6 @@ Stem::is_valid_stem (Grob *me)
   if (!lh && !beam)
     return false;
 
-  if (lh && robust_scm2int (lh->get_property ("duration-log"), 0) < 1)
-    return false;
-
   if (is_invisible (me))
     return false;
 
@@ -875,7 +884,7 @@ Stem::offset_callback (SCM smob)
 
       Direction d = get_grob_direction (me);
       Real real_attach = head_wid.linear_combination (d * attach);
-      Real r = real_attach;
+      Real r = isnan(real_attach)? 0.0: real_attach;
 
       /* If not centered: correct for stem thickness.  */
       string style = robust_symbol2string (f->get_property ("style"), "default");