Doc: Augment section about titles (3103)

[lilypond.git] / lily / page-breaking.cc

diff --git a/lily/page-breaking.cc b/lily/page-breaking.cc
index d81e32d230108ff61bb54979837ffd9e1d121461..9a6f8f40f25c0edbe47f45ecde1780c2babc89b6 100644 (file)
--- a/lily/page-breaking.cc
+++ b/lily/page-breaking.cc
@@ -466,7 +466,7 @@ Page_breaking::systems ()
           pb->unprotect ();
         }
     }
-  return scm_append (scm_reverse (ret));
+  return scm_append (scm_reverse_x (ret, SCM_EOL));
 }
 
 SCM
@@ -504,7 +504,7 @@ Page_breaking::page_height (int page_num, bool last) const
   // This means that we won't cache properly if page_num is negative or
   // if calc_height returns a negative number.  But that's likely to
   // be rare, so it shouldn't affect performance.
-  vector<Real>& cache = last ? last_page_height_cache_ : page_height_cache_;
+  vector<Real> &cache = last ? last_page_height_cache_ : page_height_cache_;
   if (page_num >= 0 && (int) cache.size () > page_num && cache[page_num] >= 0)
     return cache[page_num];
   else
@@ -552,7 +552,7 @@ Page_breaking::draw_page (SCM systems, SCM configuration, int page_num, bool las
 {
   // Create a stencil for each system.
   SCM paper_systems = SCM_EOL;
-  for (SCM s = scm_reverse (systems); scm_is_pair (s); s = scm_cdr (s))
+  for (SCM s = systems; scm_is_pair (s); s = scm_cdr (s))
     {
       SCM paper_system = scm_car (s);
       if (Grob *g = unsmob_grob (scm_car (s)))
@@ -563,12 +563,10 @@ Page_breaking::draw_page (SCM systems, SCM configuration, int page_num, bool las
 
       paper_systems = scm_cons (paper_system, paper_systems);
     }
+  paper_systems = scm_reverse_x (paper_systems, SCM_EOL);
 
   // Create the page and draw it.
   SCM page = make_page (page_num, last);
-  SCM page_module = scm_c_resolve_module ("scm page");
-  SCM page_stencil = scm_c_module_lookup (page_module, "page-stencil");
-  page_stencil = scm_variable_ref (page_stencil);
 
   Prob *p = unsmob_prob (page);
   p->set_property ("lines", paper_systems);
@@ -582,7 +580,6 @@ Page_breaking::draw_page (SCM systems, SCM configuration, int page_num, bool las
   foot = Page_layout_problem::add_footnotes_to_footer (footnotes, foot, book_);
 
   p->set_property ("foot-stencil", foot.smobbed_copy ());
-  scm_apply_1 (page_stencil, page, SCM_EOL);
 
   return page;
 }
@@ -602,10 +599,11 @@ Page_breaking::make_pages (vector<vsize> lines_per_page, SCM systems)
     label_page_table = SCM_EOL;
 
   // Build a list of (systems configuration . footnote-count) triples.
-  // Note that we lay out
-  // the staves and find the configurations before drawing anything. Some
+  // Note that we lay out the staves and find the configurations,
+  // but we do not draw anything in this function.  It is important
+  // that all staves are laid out vertically before any are drawn; some
   // grobs (like tuplet brackets) look at their neighbours while drawing
-  // themselves. If this happens before the neighbouring staves have
+  // themselves.  If this happens before the neighbouring staves have
   // been laid out, bad side-effects could happen (in particular,
   // Align_interface::align_to_ideal_distances might be called).
   SCM systems_configs_fncounts = SCM_EOL;
@@ -641,7 +639,9 @@ Page_breaking::make_pages (vector<vsize> lines_per_page, SCM systems)
       systems = scm_list_tail (systems, line_count);
     }
 
-  // Now it's safe to make the pages.
+  // TODO: previously, the following loop caused the systems to be
+  // drawn.  Now that we no longer draw anything in Page_breaking,
+  // it is safe to merge these two loops.
   int page_num = first_page_number + lines_per_page.size () - 1;
   for (SCM s = systems_configs_fncounts; scm_is_pair (s); s = scm_cdr (s))
     {
@@ -680,14 +680,6 @@ Page_breaking::make_pages (vector<vsize> lines_per_page, SCM systems)
   return ret;
 }
 
-/* The page-turn-page-breaker needs to have a line-breaker between any two
-   columns with non-NULL page-turn-permission.
-
-   The optimal-breaker needs to have a line-breaker between any two columns
-   with page-break-permission = 'force.
-
-   By using a grob predicate, we can accommodate both of these uses.
-*/
 void
 Page_breaking::create_system_list ()
 {
@@ -711,6 +703,14 @@ Page_breaking::create_system_list ()
     system_specs_.push_back (System_spec ());
 }
 
+/* The page-turn-page-breaker needs to have a line-breaker between any two
+   columns with non-NULL page-turn-permission.
+
+   The optimal-breaker needs to have a line-breaker between any two columns
+   with page-break-permission = 'force.
+
+   By using a grob predicate, we can accommodate both of these uses.
+*/
 void
 Page_breaking::find_chunks_and_breaks (Break_predicate is_break, Prob_break_predicate prob_is_break)
 {
@@ -1224,11 +1224,11 @@ Page_breaking::blank_page_penalty () const
   SCM penalty_sym;
 
   if (is_last ())
-    penalty_sym = ly_symbol2scm ("blank-last-page-force");
+    penalty_sym = ly_symbol2scm ("blank-last-page-penalty");
   else if (ends_score ())
-    penalty_sym = ly_symbol2scm ("blank-after-score-page-force");
+    penalty_sym = ly_symbol2scm ("blank-after-score-page-penalty");
   else
-    penalty_sym = ly_symbol2scm ("blank-page-force");
+    penalty_sym = ly_symbol2scm ("blank-page-penalty");
 
   Break_position const &pos = breaks_[current_end_breakpoint_];
   if (Paper_score *ps = system_specs_[pos.system_spec_index_].pscore_)