lily/include/linespace.hh

   1 /*
   2   linespace.hh -- declare  Spacing_problem
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1996, 1997--1998 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7 */
   8
   9 #error
  10
  11 #ifndef LINESPACE_HH
  12 #define LINESPACE_HH
  13
  14 #include "plist.hh"
  15 #include "array.hh"
  16 #include "vector.hh"
  17 #include "interval.hh"
  18 #include "pointer.hh"
  19
  20
  21 /** the problem, given by the columns (which include constraints) and
  22     intercolumn spacing. The problem is:
  23
  24     Generate a spacing which
  25     \begin{itemize}
  26     \item
  27     Satisfies spacing constraints (notes can't be printed through each other)
  28     \item
  29     Looks good, ie tries to conform to  an ideal spacing as much as possible.
  30     \end{itemize}
  31     This is converted by regarding idealspacing as "springs" attached
  32     to columns. The equilibrium of one spring is the ideal
  33     distance. The columns have a size, this imposes "hard" constraints
  34     on the distances. This transforms the problem into a quadratic
  35     programming problem with linear constraints.
  36
  37     The quality is given by the total potential energy in the
  38     springs. The lower the energy, the better the configuration.
  39
  40     TODO: make item widths work per pstaff.
  41
  42 */
  43 class Spacing_problem {
  44     PointerList<Idealspacing *> ideal_p_list_;
  45     Array<Column_info> cols;
  46     Array<Column_info> loose_col_arr_;
  47
  48     /// mark column #i# as being loose.
  49     void loosen_column (int i);
  50     /// the index of #c# in #cols#
  51     int col_id (Paper_column const *c) const;
  52
  53     /// generate an (nonoptimal) solution
  54     Vector find_initial_solution() const;
  55
  56     /// check if problem is too tight
  57     bool check_feasible() const;
  58
  59     /// does #this# contain the column #w#?
  60     bool contains (Paper_column const *w);
  61
  62     /// make the energy function
  63     void make_matrices (Matrix &quad, Vector &lin,Real&) const;
  64
  65     /// generate the LP constraints
  66     void make_constraints (Mixed_qp& lp) const;
  67
  68
  69     void handle_loose_cols();
  70     void position_loose_cols (Vector &) const;
  71     void print_ideal (Idealspacing const *) const;
  72     Vector try_initial_solution() const;
  73     void calcideal();
  74
  75     Score_column* scol_l (int);
  76     void connect (int i,int j, Real,Real);
  77 public:
  78     static Line_spacer *constructor() {
  79         return new Line_spacer;
  80     }
  81     Array<Paper_column*> error_pcol_l_arr() const;
  82
  83     virtual   Array<Real> solve() const;
  84     virtual void add_column (Paper_column  *, bool fixed=false, Real fixpos=0.0);
  85
  86
  87     virtual Vector default_solution() contains {
  88         return try_initial_solution() ;
  89     }
  90     virtual   bool check_constraints (Vector v) const;
  91     virtual    void OK() const;
  92     virtual    void print() const;
  93     virtual    void prepare();
  94 };