/*
  spacing-options.cc -- implement Spacing_options 

  source file of the GNU LilyPond music typesetter

  (c) 2006 Han-Wen Nienhuys <hanwen@lilypond.org>

*/

#include "spacing-options.hh"
#include "spacing-spanner.hh"
#include "grob.hh"
#include "misc.hh"
#include "moment.hh"
#include "spanner.hh"

void
Spacing_options::init_from_grob (Grob *me)
{
  increment_ = robust_scm2double (me->get_property ("spacing-increment"), 1);

  packed_ = to_boolean (me->get_property ("packed-spacing"));
  stretch_uniformly_ = to_boolean (me->get_property ("uniform-stretching"));
  float_nonmusical_columns_
    = to_boolean (me->get_property ("strict-note-spacing"));
  float_grace_columns_
    = to_boolean (me->get_property ("strict-grace-spacing"));
  shortest_duration_space_ = robust_scm2double (me->get_property ("shortest-duration-space"), 1);


  Moment shortest_dur = robust_scm2moment (me->get_property ("common-shortest-duration"),
					   Moment (Rational (1,8), Rational (1,16)));

  if (shortest_dur.main_part_)
    global_shortest_ = shortest_dur.main_part_;
  else
    global_shortest_ = shortest_dur.grace_part_;
}

Spacing_options::Spacing_options ()
{
  packed_ = false;
  stretch_uniformly_ = false;
  float_nonmusical_columns_ = false;
  float_grace_columns_ = false;

  shortest_duration_space_ = 2.0;
  increment_ = 1.2;

  global_shortest_ = Rational (1, 8);
}



/*
  Get the measure wide ant for arithmetic spacing.
*/
Real
Spacing_options::get_duration_space (Rational d,
				     bool *expand_only) const
{
  Real k = shortest_duration_space_;

  if (d < global_shortest_)
    {
      /*
	We don't space really short notes using the log of the
	duration, since it would disproportionally stretches the long
	notes in a piece. In stead, we use geometric spacing with constant 0.5
	(i.e. linear.)

	This should probably be tunable, to use other base numbers.

	In Mozart hrn3 by EB., we have 8th note = 3.9 mm (total), 16th note =
	3.6 mm (total).  head-width = 2.4, so we 1.2mm for 16th, 1.5
	mm for 8th. (white space), suggesting that we use

	(1.2 / 1.5)^{-log2(duration ratio)}


      */
      Rational ratio = d / global_shortest_;

      return ((k - 1) + double (ratio)) * increment_;
    }
  else
    {
      /*
	John S. Gourlay. ``Spacing a Line of Music, '' Technical
	Report OSU-CISRC-10/87-TR35, Department of Computer and
	Information Science, The Ohio State University, 1987.
      */
      Real log = log_2 (global_shortest_);
      k -= log;
      *expand_only = false;

      return (log_2 (d) + k) * increment_;
    }
}

