lily/stem-tremolo.cc

   1 /*
   2   stem-tremolo.cc --  implement Stem_tremolo
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c)  1997--2003 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7
   8  */
   9
  10 #include "stem-tremolo.hh"
  11 #include "warn.hh"
  12 #include "beam.hh"
  13 #include "paper-def.hh"
  14 #include "lookup.hh"
  15 #include "stem.hh"
  16 #include "item.hh"
  17 #include "staff-symbol-referencer.hh"
  18 #include "directional-element-interface.hh"
  19
  20 /*
  21   TODO:
  22     lengthen stem if necessary
  23  */
  24 MAKE_SCHEME_CALLBACK (Stem_tremolo,dim_callback,2);
  25
  26 /*
  27   todo: init with cons.
  28  */
  29 SCM
  30 Stem_tremolo::dim_callback (SCM e, SCM)
  31 {
  32   Grob * se = unsmob_grob (e);
  33
  34   Real space = Staff_symbol_referencer::staff_space (se);
  35   return ly_interval2scm (Interval (-space, space));
  36 }
  37
  38 /*
  39   ugh ?  --from Slur
  40  */
  41 MAKE_SCHEME_CALLBACK (Stem_tremolo, height, 2);
  42 SCM
  43 Stem_tremolo::height (SCM smob, SCM ax)
  44 {
  45   Axis a = (Axis)gh_scm2int (ax);
  46   Grob * me = unsmob_grob (smob);
  47   assert (a == Y_AXIS);
  48
  49   SCM mol = me->get_uncached_molecule ();
  50
  51   if (Molecule *m = unsmob_molecule (mol))
  52     return ly_interval2scm (m->extent (a));
  53   else
  54     return ly_interval2scm (Interval());
  55 }
  56
  57
  58 MAKE_SCHEME_CALLBACK (Stem_tremolo,brew_molecule,1);
  59 SCM
  60 Stem_tremolo::brew_molecule (SCM smob)
  61 {
  62   Grob *me= unsmob_grob (smob);
  63   Grob * stem = unsmob_grob (me->get_grob_property ("stem"));
  64   Grob * beam = Stem::get_beam (stem);
  65
  66   Real dydx;
  67   if (beam)
  68     {
  69       Real dy = 0;
  70       SCM s = beam->get_grob_property ("positions");
  71       if (gh_pair_p (s))
  72         {
  73           dy = -gh_scm2double (gh_car (s)) +gh_scm2double (gh_cdr (s));
  74         }
  75       Real dx = Beam::last_visible_stem (beam)->relative_coordinate (0, X_AXIS)
  76         - Beam::first_visible_stem (beam)->relative_coordinate (0, X_AXIS);
  77       dydx = dx ? dy/dx : 0;
  78     }
  79   else
  80     // urg
  81     dydx = 0.25;
  82
  83   Real ss = Staff_symbol_referencer::staff_space (stem);
  84   Real thick = gh_scm2double (me->get_grob_property ("beam-thickness"));
  85   Real width = gh_scm2double (me->get_grob_property ("beam-width"));
  86   width *= ss;
  87   thick *= ss;
  88
  89   Molecule a (Lookup::beam (dydx, width, thick));
  90   a.translate (Offset (-width/2, width / 2 * dydx));
  91
  92   int tremolo_flags = 0;
  93   SCM s = me->get_grob_property ("flag-count");
  94   if (gh_number_p (s))
  95     tremolo_flags = gh_scm2int (s);
  96
  97   if (!tremolo_flags)
  98     {
  99       programming_error ("No tremolo flags?");
 100
 101       me->suicide();
 102       return SCM_EOL;
 103     }
 104
 105   /*
 106     Who the fuck is 0.81 ?
 107
 108     --hwn.
 109    */
 110   Real beam_translation = beam ? Beam::get_beam_translation (beam) : 0.81;
 111
 112   Molecule mol;
 113   for (int i = 0; i < tremolo_flags; i++)
 114     {
 115       Molecule b (a);
 116       b.translate_axis (beam_translation * i, Y_AXIS);
 117       mol.add_molecule (b);
 118     }
 119   Direction stemdir = Stem::get_direction (stem);
 120   Interval mol_ext = mol.extent (Y_AXIS);
 121
 122   // ugh, rather calc from Stem_tremolo_req
 123   int beams_i = (beam) ? (Stem::beam_multiplicity (stem).length ()+ 1): 0;
 124
 125   /*
 126     TODO.
 127    */
 128
 129
 130   Real beamthickness = 0.0;
 131   SCM sbt = (beam) ? beam->get_grob_property ("thickness") : SCM_EOL ;
 132   if (gh_number_p (sbt))
 133     {
 134       beamthickness = gh_scm2double (sbt) * ss;
 135     }
 136
 137   Real end_y
 138     = Stem::stem_end_position (stem) *ss/2
 139     - stemdir * (beams_i * beamthickness
 140                  + ((beams_i -1) >? 0) * beam_translation);
 141
 142   /*
 143     the 0.33 ss is to compensate for the size of the note head
 144    */
 145   Real chord_start_y = Stem::chord_start_y (stem) +
 146     0.33 * ss * stemdir;
 147
 148   Real padding = beam_translation;
 149
 150   /*
 151     if there is not enough space, center on remaining space,
 152     else one beamspace away from stem end.
 153    */
 154   if (stemdir * (end_y - chord_start_y) - 2*padding - mol_ext.length ()  < 0.0)
 155     {
 156       mol.translate_axis ((end_y + chord_start_y) /2.0  - mol_ext.center (),Y_AXIS);
 157     }
 158   else
 159     {
 160       mol.translate_axis (end_y - stemdir * beam_translation
 161                           -mol_ext [stemdir]
 162                           , Y_AXIS);
 163     }
 164
 165   return mol.smobbed_copy ();
 166 }
 167
 168
 169 void
 170 Stem_tremolo::set_stem (Grob*me,Grob *s)
 171 {
 172   me->set_grob_property ("stem", s->self_scm ());
 173 }
 174
 175
 176 ADD_INTERFACE (Stem_tremolo,"stem-tremolo-interface",
 177   "",
 178   "stem beam-width beam-thickness flag-count");