Fix 1460.

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

diff --git a/lily/page-breaking.cc b/lily/page-breaking.cc
index f3b1f84de3a066dcf8156465a96944c8961be50f..3272e02eefbb3471efab3be5e04a8ed28a11683f 100644 (file)
--- a/lily/page-breaking.cc
+++ b/lily/page-breaking.cc
@@ -343,9 +343,8 @@ Page_breaking::systems ()
            ->get_broken_system_grobs ();
          ret = scm_cons (lines, ret);
        }
-      else
+      else if (Prob *pb = system_specs_[sys].prob_)
        {
-         Prob *pb = system_specs_[sys].prob_;
          ret = scm_cons (scm_list_1 (pb->self_scm ()), ret);
          pb->unprotect ();
        }
@@ -465,6 +464,9 @@ Page_breaking::draw_page (SCM systems, SCM configuration, int page_num, bool las
 SCM
 Page_breaking::make_pages (vector<vsize> lines_per_page, SCM systems)
 {
+  if (scm_is_null (systems))
+    return SCM_EOL;
+
   int first_page_number
     = robust_scm2int (book_->paper_->c_variable ("first-page-number"), 1);
   SCM ret = SCM_EOL;
@@ -554,6 +556,8 @@ Page_breaking::create_system_list ()
           system_specs_.push_back (System_spec (pb));
         }
     }
+  if (!system_specs_.size ())
+    system_specs_.push_back (System_spec ());
 }
 
 void
@@ -630,7 +634,7 @@ Page_breaking::find_chunks_and_breaks (Break_predicate is_break, Prob_break_pred
            }
          line_breaking_.push_back (Constrained_breaking (system_specs_[i].pscore_, line_breaker_columns));
        }
-      else
+      else if (system_specs_[i].prob_)
        {
          bool break_point = prob_is_break && prob_is_break (system_specs_[i].prob_);
          if (break_point || i == system_specs_.size () - 1)
@@ -832,7 +836,9 @@ Page_breaking::cache_line_details (vsize configuration_index)
          else
            {
              assert (div[i] == 1);
-             uncompressed_line_details_.push_back (Line_details (system_specs_[sys].prob_, book_->paper_));
+             uncompressed_line_details_.push_back (system_specs_[sys].prob_
+                                                   ? Line_details (system_specs_[sys].prob_, book_->paper_)
+                                                   : Line_details ());
            }
        }
       cached_line_details_ = compress_lines (uncompressed_line_details_);
@@ -1131,6 +1137,9 @@ Page_breaking::space_systems_on_n_or_one_more_pages (vsize configuration, vsize
 Page_spacing_result
 Page_breaking::space_systems_on_best_pages (vsize configuration, vsize first_page_num)
 {
+  if (systems_per_page_ > 0)
+    return space_systems_with_fixed_number_per_page (configuration, first_page_num);
+
   cache_line_details (configuration);
   Page_spacer ps (cached_line_details_, first_page_num, this);