1 files changed, 95 insertions, 0 deletions
diff --git a/hdr/linespace.hh b/hdr/linespace.hh
new file mode 100644
index 0000000000..54704508e6
--- /dev/null
+++ b/hdr/linespace.hh
@@ -0,0 +1,95 @@
+#ifndef PROBLEM_HH
+#define PROBLEM_HH
+
+#include "glob.hh"
+#include "plist.hh"
+#include "vray.hh"
+#include "pcol.hh"
+#include "matrix.hh"
+
+/// helper struct for #Spacing_problem#
+struct Colinfo {
+    const PCol *pcol_;
+    bool fixed;
+    Real fixpos;
+    Colinfo();
+    void print() const;
+    Real minright() const { return pcol_->width().max; }
+    Real minleft() const { return -pcol_->width().min; }
+};
+
+
+/// spacing for one line.
+class Spacing_problem {
+    svec<const Idealspacing*> ideals;
+    svec<Colinfo> cols;
+
+    /// the index of #c# in #cols#
+    int col_id(const PCol *c) const;
+
+    /// generate an (nonoptimal) solution
+    Vector find_initial_solution() const;
+
+    /// check if problem is too tight
+    bool check_feasible() const;
+    /// does #this# contain the column #w#? 
+    bool contains(const PCol *w);
+
+    /// make the energy function
+    void make_matrices(Matrix &quad, Vector &lin,Real&) const;
+
+    /// generate the LP constraints
+    void make_constraints(Mixed_qp& lp) const;
+
+public:
+    /// solve the spacing problem
+    svec<Real> solve() const;
+    /**
+    return the column positions, and the energy (last element)
+    */
+    /// add a idealspacing to the problem.
+    void add_ideal(const Idealspacing *i);
+    
+    /**
+    One pair of columns can have no, one or more idealspacings,
+    since they can be "summed" if the columns to which #i# refers are
+    not in this problem, the spacing is ignored.
+    */
+    
+    
+    /// add a col to the problem
+    void add_column(const PCol *, bool fixed=false, Real fixpos=0.0);
+    /** columns have to be added left to right. The column contains
+      info on it's minimum width.
+    */
+
+
+    bool check_constraints(Vector v) const;
+
+    Vector try_initial_solution() const;
+    void OK() const;
+    void print() const;
+    void print_ideal(const Idealspacing*)const;
+};
+
+
+/** the problem, given by the columns (which include constraints) and
+    intercolumn spacing. The problem is:
+
+    Generate a spacing which
+    \begin{itemize}
+    \item
+    Satisfies spacing constraints (notes can't be printed through each other)
+    \item
+    Looks good, ie tries to conform to  an ideal spacing as much as possible.
+    \end{itemize}
+    This is converted by regarding idealspacing as "springs" attached
+    to columns. The equilibrium of one spring is the ideal
+    distance. The columns have a size, this imposes "hard" constraints
+    on the distances. This transforms the problem into a quadratic
+    programming problem with linear constraints.
+
+    The quality is given by the total potential energy in the
+    springs. The lower the energy, the better the configuration.
+*/
+#endif