lily/include/page-spacing.hh

   1 /*
   2   page-spacing.hh -- routines for spacing systems
   3   vertically across pages
   4
   5   source file of the GNU LilyPond music typesetter
   6
   7   (c) 2006--2007 Joe Neeman <joeneeman@gmail.com>
   8 */
   9
  10 #ifndef PAGE_SPACING_HH
  11 #define PAGE_SPACING_HH
  12
  13 #include "constrained-breaking.hh"
  14 #include "page-spacing-result.hh"
  15
  16
  17 /* for page_count > 2, we use a dynamic algorithm similar to
  18    constrained-breaking -- we have a class that stores the intermediate
  19    calculations so they can be reused for querying different page counts.
  20 */
  21 class Page_spacer
  22 {
  23 public:
  24   Page_spacer (vector<Line_details> const &lines, vsize first_page_num, Page_breaking const*);
  25   Page_spacing_result solve (vsize page_count);
  26
  27 private:
  28   struct Page_spacing_node
  29   {
  30     Page_spacing_node ()
  31     {
  32       demerits_ = infinity_f;
  33       force_ = infinity_f;
  34       penalty_ = infinity_f;
  35       prev_ = VPOS;
  36     }
  37
  38     Real demerits_;
  39     Real force_;
  40     Real penalty_;
  41     vsize prev_;
  42   };
  43
  44   Page_breaking const *breaker_;
  45   vsize first_page_num_;
  46   vector<Line_details> lines_;
  47   Matrix<Page_spacing_node> state_;
  48   vsize max_page_count_;
  49
  50   bool ragged_;
  51   bool ragged_last_;
  52
  53   void resize (vsize page_count);
  54   bool calc_subproblem (vsize page, vsize lines);
  55 };
  56
  57 struct Page_spacing
  58 {
  59   Real force_;
  60   Real page_height_;
  61   Real rod_height_;
  62   Real spring_len_;
  63   Real inverse_spring_k_;
  64   Real page_top_space_;
  65
  66   Line_details last_line_;
  67   Line_details first_line_;
  68
  69   Page_spacing (Real page_height, Real page_top_space)
  70   {
  71     page_height_ = page_height;
  72     page_top_space_ = page_top_space;
  73     clear ();
  74   }
  75
  76   void calc_force ();
  77   void resize (Real new_height);
  78   void append_system (const Line_details &line);
  79   void prepend_system (const Line_details &line);
  80   void clear ();
  81 };
  82
  83 #endif /* PAGE_SPACING_HH */