line_count fixes

1. implementation does not assume staff centred at zero
2. where used for determining whether something falls on a line,
   use Staff_symbol_referencer::on_line or on_staff_line
3. where used for determining whether something is within staff or not,
   use Staff_symbol_referencer::staff_span

9 files changed, 117 insertions, 51 deletions

diff --git a/lily/bar-line.cc b/lily/bar-line.cc
index 0cd0339235..7da72ba321 100644
--- a/lily/bar-line.cc
+++ b/lily/bar-line.cc
@@ -25,8 +25,12 @@
 #include "lookup.hh"
 #include "output-def.hh"
 #include "paper-column.hh"
+#include "staff-symbol.hh"
 #include "staff-symbol-referencer.hh"
 
+#include <set>
+
+
 MAKE_SCHEME_CALLBACK (Bar_line, calc_bar_extent, 1)
 SCM
 Bar_line::calc_bar_extent (SCM smob)
@@ -112,15 +116,62 @@ Bar_line::compound_barline (Grob *me, string str, Interval const &extent,
   Stencil thick = simple_barline (me, fatline, extent, rounded);
   Stencil dot = Font_interface::get_default_font (me)->find_by_name ("dots.dot");
 
-  int lines = Staff_symbol_referencer::line_count (me);
-  Real dist
-    = ((lines & 1 || lines == 0)
-       ? 1
-       : (staff_space < 2 ? 2 : .5)) * staff_space;
+  /*
+    the two dots of the repeat sign should be centred at the middle of
+    the staff and both should avoid staff lines
+  */
+  Real centre = 0.0, dist = 1.0;
+  if (staff_space)
+    {
+      if (Grob *staff = Staff_symbol_referencer::get_staff_symbol (me))
+        {
+          std::vector<Real> linepos = Staff_symbol::line_positions (staff);
+          if (!linepos.empty ())
+            {
+              centre = Staff_symbol::line_span (staff).center ();
+
+              /*
+                fold the staff into two at centre and find the first gap
+                big enough to hold a dot and some space below and above
+              */
+              std::set<Real> half_staff;
+              half_staff.insert (0.0);
+              for (std::vector<Real>::const_iterator
+                     i = linepos.begin (), e = linepos.end ();
+                   i != e;
+                   ++i)
+                half_staff.insert (fabs (*i - centre));
+
+              /*
+                gap is measured like line-positions;
+                1.0 for dot diameter, twice the staffline width for the
+                gap above and below and one more staffline width for the
+                two half stafflines
+              */
+              Real const gap_to_find = (1.0 + 3 * staffline) / staff_space;
+              dist = *half_staff.rbegin () * 2 + gap_to_find;
+              for (std::set<Real>::const_iterator
+                     i0 = half_staff.begin (), i1 = i0, e = half_staff.end ();
+                   ++i1 != e;
+                   i0 = i1)
+                if (*i1 - *i0 > gap_to_find)
+                  {
+                    dist = *i0 + *i1;
+                    break;
+                  }
+            }
+        }
+    }
+  else
+    dist += 3 * staffline;
+
+  if (staff_space == 0.0)
+    staff_space = 1.0;
+
   Stencil colon (dot);
-  colon.translate_axis (dist, Y_AXIS);
+  colon.translate_axis (dist * staff_space / 2, Y_AXIS);
   colon.add_stencil (dot);
-  colon.translate_axis (-dist / 2, Y_AXIS);
+  colon.translate_axis ((centre - dist / 2) * staff_space / 2, Y_AXIS);
 
   Real const h = extent.length ();
   Stencil m;
diff --git a/lily/beam.cc b/lily/beam.cc
index 49253434c0..d73169a917 100644
--- a/lily/beam.cc
+++ b/lily/beam.cc
@@ -675,7 +675,7 @@ Beam::print (SCM grob)
 
       // we need two translations: the normal one and
       // the one of the lowest segment
-      int idx[] = {i, extreme};
+      size_t idx[] = {i, extreme};
       Real translations[2];
 
       for (int j = 0; j < 2; j++)
@@ -1274,16 +1274,16 @@ Beam::rest_collision_callback (SCM smob, SCM prev_offset)
   Real shift = d * min (d * (beam_y - d * minimum_distance - rest_dim), 0.0);
 
   shift /= staff_space;
-  Real rad = Staff_symbol_referencer::line_count (rest) * staff_space / 2;
 
   /* Always move discretely by half spaces */
   shift = ceil (fabs (shift * 2.0)) / 2.0 * sign (shift);
 
+  Interval staff_span = Staff_symbol_referencer::staff_span (rest);
+  staff_span *= staff_space / 2;
+
   /* Inside staff, move by whole spaces*/
-  if ((rest_extent[d] + staff_space * shift) * d
-      < rad
-      || (rest_extent[-d] + staff_space * shift) * -d
-      < rad)
+  if (staff_span.contains (rest_extent[d] + staff_space * shift)
+      || staff_span.contains (rest_extent[-d] + staff_space * shift))
     shift = ceil (fabs (shift)) * sign (shift);
 
   return scm_from_double (offset + staff_space * shift);
diff --git a/lily/breathing-sign.cc b/lily/breathing-sign.cc
index a3d9637bef..02b29858af 100644
--- a/lily/breathing-sign.cc
+++ b/lily/breathing-sign.cc
@@ -81,13 +81,19 @@ Breathing_sign::divisio_maior (SCM smob)
    * more than half the size of the staff, such that the endings of
    * the line are in the middle of a staff space.
    */
-  int lines = Staff_symbol_referencer::line_count (me);
-  int height = lines / 2; // little more than half of staff size
-  if ((lines & 1) != (height & 1))
-    height++; // ensure endings are centered in staff space
+  Interval ydim = Staff_symbol_referencer::staff_span (me);
+  ydim.widen (-0.25 * ydim.delta ());
+  for (UP_and_DOWN (i))
+    {
+      int const int_dim = (int) ydim[i];
+      if (int_dim == ydim[i]
+          && Staff_symbol_referencer::on_staff_line (me, int_dim))
+        ydim[i] += i;
+    }
+
+  ydim *= 1.0 / Staff_symbol_referencer::staff_space (me);
 
   Interval xdim (0, thickness);
-  Interval ydim (-0.5 * height, +0.5 * height);
   Box b (xdim, ydim);
   Stencil out = Lookup::round_filled_box (b, blotdiameter);
   return out.smobbed_copy ();
@@ -102,20 +108,15 @@ Breathing_sign::divisio_maxima (SCM smob)
 {
   Grob *me = unsmob_grob (smob);
   Real staff_space = Staff_symbol_referencer::staff_space (me);
-  Real staff_size;
   Real thickness = Staff_symbol_referencer::line_thickness (me);
   thickness *= robust_scm2double (me->get_property ("thickness"), 1.0);
 
-  if (Staff_symbol_referencer::get_staff_symbol (me))
-    staff_size = (Staff_symbol_referencer::line_count (me) - 1) * staff_space;
-  else
-    staff_size = 0.0;
-
   Real blotdiameter = me->layout ()->get_dimension (ly_symbol2scm ("blot-diameter"));
 
   // like a "|" type bar
   Interval xdim (0, thickness);
-  Interval ydim (-0.5 * staff_size, +0.5 * staff_size);
+  Interval ydim = Staff_symbol_referencer::staff_span (me);
+  ydim *= staff_space / 2;
   Box b (xdim, ydim);
   Stencil out = Lookup::round_filled_box (b, blotdiameter);
   return out.smobbed_copy ();
@@ -130,20 +131,15 @@ Breathing_sign::finalis (SCM smob)
 {
   Grob *me = unsmob_grob (smob);
   Real staff_space = Staff_symbol_referencer::staff_space (me);
-  Real staff_size;
   Real thickness = Staff_symbol_referencer::line_thickness (me);
   thickness *= robust_scm2double (me->get_property ("thickness"), 1.0);
 
-  if (Staff_symbol_referencer::get_staff_symbol (me))
-    staff_size = (Staff_symbol_referencer::line_count (me) - 1) * staff_space;
-  else
-    staff_size = 0.0;
-
   Real blotdiameter = me->layout ()->get_dimension (ly_symbol2scm ("blot-diameter"));
 
   // like a "||" type bar
   Interval xdim (0, thickness);
-  Interval ydim (-0.5 * staff_size, +0.5 * staff_size);
+  Interval ydim = Staff_symbol_referencer::staff_span (me);
+  ydim *= staff_space / 2;
   Box b (xdim, ydim);
   Stencil line1 = Lookup::round_filled_box (b, blotdiameter);
   Stencil line2 (line1);
diff --git a/lily/custos.cc b/lily/custos.cc
index 00da1d53d1..1366202f72 100644
--- a/lily/custos.cc
+++ b/lily/custos.cc
@@ -62,7 +62,6 @@ Custos::print (SCM smob)
     = to_dir (me->get_property ("neutral-direction"));
 
   int pos = Staff_symbol_referencer::get_rounded_position (me);
-  int sz = Staff_symbol_referencer::line_count (me) - 1;
 
   string font_char = "custodes." + style + ".";
   if (pos < neutral_pos)
@@ -77,7 +76,7 @@ Custos::print (SCM smob)
     font_char += "d";
 
   if (adjust)
-    font_char += (((pos ^ sz) & 0x1) == 0) ? "1" : "0";
+    font_char += Staff_symbol_referencer::on_line (me, pos) ? "1" : "0";
   else
     font_char += "2";
 
diff --git a/lily/rest-collision.cc b/lily/rest-collision.cc
index 8ba647e201..0e7a01c5a7 100644
--- a/lily/rest-collision.cc
+++ b/lily/rest-collision.cc
@@ -250,19 +250,14 @@ Rest_collision::calc_positioning_done (SCM smob)
           Real y = dir * max (0.0,
                               -dir * restdim[-dir] + dir * notedim[dir] + minimum_dist);
 
-          int stafflines = Staff_symbol_referencer::line_count (me);
-          if (!stafflines)
-            {
-              programming_error ("no staff line count");
-              stafflines = 5;
-            }
-
           // move discretely by half spaces.
           int discrete_y = dir * int (ceil (y / (0.5 * dir * staff_space)));
 
+          Interval staff_span = Staff_symbol_referencer::staff_span (rest);
+          staff_span.widen (1);
           // move by whole spaces inside the staff.
-          if (fabs (Staff_symbol_referencer::get_position (rest)
-                    + discrete_y) < stafflines + 1)
+          if (staff_span.contains
+              (Staff_symbol_referencer::get_position (rest) + discrete_y))
             {
               discrete_y = dir * int (ceil (dir * discrete_y / 2.0) * 2.0);
             }
diff --git a/lily/rest.cc b/lily/rest.cc
index 9057e45af1..8e45405de2 100644
--- a/lily/rest.cc
+++ b/lily/rest.cc
@@ -37,7 +37,6 @@ Rest::y_offset_callback (SCM smob)
 {
   Grob *me = unsmob_grob (smob);
   int duration_log = scm_to_int (me->get_property ("duration-log"));
-  int line_count = Staff_symbol_referencer::line_count (me);
   Real ss = Staff_symbol_referencer::staff_space (me);
 
   bool position_override = scm_is_number (me->get_property ("staff-position"));
@@ -69,7 +68,7 @@ Rest::y_offset_callback (SCM smob)
         make a semibreve rest hang from the next line,
         except for a single line staff
       */
-      if (duration_log == 0 && line_count > 1)
+      if (duration_log == 0 && Staff_symbol_referencer::line_count (me) > 1)
         pos += 2;
 
       /*
diff --git a/lily/slur-scoring.cc b/lily/slur-scoring.cc
index eaadde5c58..9e50984243 100644
--- a/lily/slur-scoring.cc
+++ b/lily/slur-scoring.cc
@@ -590,8 +590,7 @@ Slur_score_state::move_away_from_staffline (Real y,
       * 2.0 / staff_space_;
 
   if (fabs (pos - my_round (pos)) < 0.2
-      && Staff_symbol_referencer::on_line (on_staff, (int) rint (pos))
-      && Staff_symbol_referencer::line_count (on_staff) - 1 >= rint (pos))
+      && Staff_symbol_referencer::on_staff_line (on_staff, (int) rint (pos)))
     y += 1.5 * staff_space_ * dir_ / 10;
 
   return y;
diff --git a/lily/time-signature.cc b/lily/time-signature.cc
index ad553e4229..082b62a93c 100644
--- a/lily/time-signature.cc
+++ b/lily/time-signature.cc
@@ -23,6 +23,7 @@
 #include "font-interface.hh"
 #include "international.hh"
 #include "output-def.hh"
+#include "staff-symbol.hh"
 #include "staff-symbol-referencer.hh"
 #include "text-interface.hh"
 #include "warn.hh"
@@ -57,8 +58,35 @@ Time_signature::print (SCM smob)
   else
     m = numbered_time_signature (me, n, d);
 
-  if (Staff_symbol_referencer::line_count (me) % 2 == 0)
-    m.translate_axis (Staff_symbol_referencer::staff_space (me) / 2, Y_AXIS);
+  /*
+    position the signature centred on the staff line
+    nearest to the middle of the staff
+  */
+  if (Grob *staff = Staff_symbol_referencer::get_staff_symbol (me))
+    {
+      std::vector<Real> const linepos = Staff_symbol::line_positions (staff);
+      if (!linepos.empty ())
+        {
+          Interval const span = Staff_symbol::line_span (staff);
+          Real const mid = span.center ();
+          Real pos = linepos.front ();
+          Real dist = fabs (pos - mid);
+          for (std::vector<Real>::const_iterator
+                 i = linepos.begin (), e = linepos.end ();
+               ++i != e;)
+            {
+              double const d = fabs (*i - mid);
+              if (d < dist)
+                {
+                  pos = *i;
+                  dist = d;
+                }
+            }
+
+          m.translate_axis
+            (pos * Staff_symbol_referencer::staff_space (me) / 2, Y_AXIS);
+        }
+    }
 
   return m.smobbed_copy ();
 }
diff --git a/lily/vaticana-ligature.cc b/lily/vaticana-ligature.cc
index 7420db3ec1..deb0218bd0 100644
--- a/lily/vaticana-ligature.cc
+++ b/lily/vaticana-ligature.cc
@@ -37,8 +37,7 @@ vaticana_brew_cauda (Grob *me,
                      Real blotdiameter)
 {
   bool on_staffline = Staff_symbol_referencer::on_line (me, pos);
-  int interspaces = Staff_symbol_referencer::line_count (me) - 1;
-  bool above_staff = pos > interspaces;
+  bool above_staff = pos > Staff_symbol_referencer::staff_span (me)[UP];
 
   if (delta_pitch > -1)
     {