1 files changed, 179 insertions, 0 deletions
diff --git a/src/beam.cc b/src/beam.cc
new file mode 100644
index 0000000000..49214c91f2
--- /dev/null
+++ b/src/beam.cc
@@ -0,0 +1,179 @@
+#include "beam.hh"
+#include "debug.hh"
+#include "symbol.hh"
+#include "molecule.hh"
+#include "leastsquares.hh"
+#include "pcol.hh"
+#include "stem.hh"
+#include "paper.hh"
+#include "lookup.hh"
+
+
+struct Stem_info {
+    Real x;
+    Real idealy;
+    Real miny;
+    int no_beams;
+
+    Stem_info(){}
+    Stem_info(const Stem*);
+};
+Stem_info::Stem_info(const Stem*s)
+{
+    x = s->hpos();
+    int dir = s->dir;
+    idealy  = MAX(dir*s->top, dir*s->bot);
+    miny = MAX(dir*s->minnote, dir*s-> maxnote);
+    assert(miny <= idealy);
+    no_beams = s->flag;
+}
+
+/****************/
+
+Beam::Beam()
+{
+    slope = 0;
+    left_pos = 0.0;
+    dir =0;
+}
+
+void
+Beam::add(Stem*s)
+{
+    stems.bottom().add(s);
+    s->print_flag = false;
+}
+
+void
+Beam::set_default_dir()
+{
+    int dirs[2];
+    dirs[0]=0; dirs[1] =0;
+    for (PCursor<Stem*> sc(stems); sc.ok(); sc++) {
+	sc->set_default_dir();
+	dirs[(sc->dir+1)/2] ++;
+    }
+    dir =  (dirs[0] > dirs[1]) ? -1 : 1;
+    for (PCursor<Stem*> sc(stems); sc.ok(); sc++) {
+	sc->dir = dir;
+    }
+}
+
+void
+Beam::solve_slope()
+{
+    svec<Stem_info> sinfo;
+    for (PCursor<Stem* >sc(stems); sc.ok(); sc++) {
+	sc->set_default_extents();
+	Stem_info i(sc);
+	sinfo.add(i);
+    }
+    Real leftx = sinfo[0].x;
+    Least_squares l;
+    for (int i=0; i < sinfo.sz(); i++) {
+	sinfo[i].x -= leftx;
+	l.input.add(Offset(sinfo[i].x, sinfo[i].idealy));
+    }
+
+    l.minimise(slope, left_pos);
+    Real dy = 0.0;
+    for (int i=0; i < sinfo.sz(); i++) {
+	Real y = sinfo[i].x * slope + left_pos;
+	Real my = sinfo[i].miny;
+
+	if (my - y > dy)
+	    dy = my -y;	
+    }
+    left_pos += dy;
+    left_pos *= dir;    
+    slope *= dir;
+    
+    {Real inter =paper()->interline()/2;
+    Real unitslope = slope*inter;
+
+    // set beamslope, for setting stems correctly
+    // ignoring return.
+    Symbol sy = paper()->lookup_->beam(unitslope, width().length());
+    slope =unitslope / inter;
+    }
+}
+
+void
+Beam::set_stemlens()
+{
+    PCursor<Stem*> s(stems);
+    Real x0 = s->hpos();    
+    for (; s.ok() ; s++) {
+	Real x =  s->hpos()-x0;
+	s->set_stemend(left_pos + slope * x);	
+    }
+}
+
+void
+Beam::calculate()
+{
+    assert(stems.size()>1);
+    if (!dir)
+	set_default_dir();
+
+    solve_slope();
+    set_stemlens();
+}
+
+void
+Beam::process()
+{
+    calculate();
+    brew_molecule();
+}
+
+
+// todo.
+Spanner *
+Beam::broken_at(const PCol *, const PCol *) const
+{
+    return new Beam(*this);
+}
+
+void
+Beam::preprocess()
+{
+    left  = (*stems.top())   ->pcol_;
+    right = (*stems.bottom())->pcol_;    
+}
+
+Interval
+Beam::height() const
+{
+    return output->extent().y;
+}
+
+Interval
+Beam::width() const
+{
+    Beam * me = (Beam*) this;	// ugh
+    return Interval( (*me->stems.top()) ->hpos(),
+		     (*me->stems.bottom()) ->hpos() );
+}
+
+void
+Beam::brew_molecule()
+{
+    Real inter=paper()->interline()/2;
+    Real sl = slope*inter;
+    Real w =  width().length() + paper()->rule_thickness();
+    Symbol s = paper()->lookup_->beam(sl,w);
+
+    Atom a(s);
+    
+    Real dx = width().min -left->hpos;
+    a.translate(Offset(dx,left_pos*inter));
+    output = new Molecule(a);
+}
+
+void
+Beam::print()const
+{
+    mtor << "Beam, slope " <<slope << "left ypos " << left_pos<<'\n';    
+}
+