-/*
- simple-spacer.cc -- implement Simple_spacer
-
+/*
+ simple-spacer.cc -- implement Simple_spacer
+
source file of the GNU LilyPond music typesetter
-
- (c) 1999 Han-Wen Nienhuys <hanwen@cs.uu.nl>
-
- */
+ (c) 1999--2006 Han-Wen Nienhuys <hanwen@xs4all.nl>
+
+ TODO:
+ - add support for different stretch/shrink constants?
+*/
+
+#include <cstdio>
+
+#include "column-x-positions.hh"
+#include "dimensions.hh"
+#include "international.hh"
+#include "libc-extension.hh" // isinf
+#include "paper-column.hh"
+#include "simple-spacer.hh"
+#include "spaceable-grob.hh"
+#include "spring.hh"
+#include "warn.hh"
+
+/*
+ A simple spacing constraint solver. The approach:
+
+ Stretch the line uniformly until none of the constraints (rods)
+ block. It then is very wide.
+
+ Compress until the next constraint blocks,
+
+ Mark the springs over the constrained part to be non-active.
+
+ Repeat with the smaller set of non-active constraints, until all
+ constraints blocked, or until the line is as short as desired.
+
+ This is much simpler, and much much faster than full scale
+ Constrained QP. On the other hand, a situation like this will not
+ be typeset as dense as possible, because
+
+ c4 c4 c4 c4
+ veryveryverylongsyllable2 veryveryverylongsyllable2
+ " "4 veryveryverylongsyllable2 syllable4
+
+
+ can be further compressed to
+
+
+ c4 c4 c4 c4
+ veryveryverylongsyllable2 veryveryverylongsyllable2
+ " "4 veryveryverylongsyllable2 syllable4
+
+
+ Perhaps this is not a bad thing, because the 1st looks better anyway. */
+
+/*
+ positive force = expanding, negative force = compressing.
+*/
+
+Simple_spacer::Simple_spacer ()
+{
+ force_ = 0.;
+ fits_ = true;
+}
+
+Real
+Simple_spacer::force ()
+{
+ return force_;
+}
+
+bool
+Simple_spacer::fits ()
+{
+ return fits_;
+}
+
+Real
+Simple_spacer::rod_force (int l, int r, Real dist)
+{
+ Real c = range_stiffness (l, r);
+ Real d = range_ideal_len (l, r);
+ Real block_stretch = dist - d;
+ return c * block_stretch;
+}
+
+void
+Simple_spacer::add_rod (int l, int r, Real dist)
+{
+ if (isinf (dist) || isnan (dist))
+ {
+ programming_error ("ignoring weird minimum distance");
+ return;
+ }
+
+ Real block_force = rod_force (l, r, dist);
+
+ if (isinf (block_force))
+ {
+ Real spring_dist = range_ideal_len (l, r);
+ if (spring_dist < dist)
+ for (int i = l; i < r; i++)
+ springs_[i].ideal_ *= dist / spring_dist;
+
+ return;
+ }
+ force_ = max (force_, block_force);
+ for (int i = l; i < r; i++)
+ springs_[i].block_force_ = max (block_force, springs_[i].block_force_);
+}
+
+Real
+Simple_spacer::range_ideal_len (int l, int r) const
+{
+ Real d = 0.;
+ for (int i = l; i < r; i++)
+ d += springs_[i].ideal_;
+ return d;
+}
+
+Real
+Simple_spacer::range_stiffness (int l, int r) const
+{
+ Real den = 0.0;
+ for (int i = l; i < r; i++)
+ den += springs_[i].inverse_hooke_;
+
+ return 1 / den;
+}
+
+Real
+Simple_spacer::configuration_length () const
+{
+ Real l = 0.;
+ for (vsize i = 0; i < springs_.size (); i++)
+ l += springs_[i].length (force_);
+
+ return l;
+}
+
+void
+Simple_spacer::solve (Real line_len, bool ragged)
+{
+ Real conf = configuration_length ();
+
+ ragged_ = ragged;
+ line_len_ = line_len;
+ if (ragged)
+ {
+ force_ = 0;
+ fits_ = configuration_length () <= line_len_;
+ /* we need to calculate a force here to prevent a bunch of short lines */
+ if (fits_)
+ force_ = expand_line ();
+ }
+ else if (conf < line_len_)
+ force_ = expand_line ();
+ else if (conf > line_len_)
+ force_ = compress_line ();
+}
+
+Real
+Simple_spacer::expand_line ()
+{
+ double inv_hooke = 0;
+ double cur_len = configuration_length ();
+
+ fits_ = true;
+ for (vsize i=0; i < springs_.size (); i++)
+ inv_hooke += springs_[i].inverse_hooke_;
+
+ assert (cur_len <= line_len_);
+ return (line_len_ - cur_len) / inv_hooke + force_;
+}
+
+Real
+Simple_spacer::compress_line ()
+{
+ double inv_hooke = 0;
+ double cur_len = configuration_length ();
+ double cur_force = force_;
+
+ fits_ = true;
+ for (vsize i=0; i < springs_.size (); i++)
+ inv_hooke += springs_[i].inverse_hooke_;
+
+ assert (line_len_ <= cur_len);
+
+ vector<Spring_description> sorted_springs = springs_;
+ sort (sorted_springs.begin (), sorted_springs.end (), greater<Spring_description> ());
+ for (vsize i = 0; i < sorted_springs.size (); i++)
+ {
+ Spring_description sp = sorted_springs[i];
+
+ assert (sp.block_force_ <= cur_force);
+ if (isinf (sp.block_force_))
+ break;
+
+ double block_dist = (cur_force - sp.block_force_) * inv_hooke;
+ if (cur_len - block_dist <= line_len_)
+ return cur_force + (line_len_ - cur_len) / inv_hooke;
+ cur_len -= block_dist;
+ inv_hooke -= sp.inverse_hooke_;
+ cur_force = sp.block_force_;
+ }
+
+ fits_ = false;
+ return cur_force;
+}
+
+void
+Simple_spacer::add_spring (Real ideal, Real inverse_hooke)
+{
+ Spring_description description;
+
+ description.ideal_ = ideal;
+ description.inverse_hooke_ = inverse_hooke;
+ if (!description.is_sane ())
+ {
+ programming_error ("insane spring found, setting to unit");
+
+ description.inverse_hooke_ = 1.0;
+ description.ideal_ = 1.0;
+ }
+
+ description.block_force_ = -description.ideal_ / description.inverse_hooke_;
+ // block at distance 0
+
+ springs_.push_back (description);
+}
+
+vector<Real>
+Simple_spacer::spring_positions () const
+{
+ vector<Real> ret;
+ ret.push_back (0.);
+
+ for (vsize i = 0; i < springs_.size (); i++)
+ ret.push_back (ret.back () + springs_[i].length (ragged_ ? 0.0 : force_));
+ return ret;
+}
+
+/****************************************************************/
+
+Spring_description::Spring_description ()
+{
+ ideal_ = 0.0;
+ inverse_hooke_ = 0.0;
+ block_force_ = 0.0;
+}
+
+bool
+Spring_description::is_sane () const
+{
+ return (inverse_hooke_ >= 0)
+ && ideal_ > 0
+ && !isinf (ideal_) && !isnan (ideal_);
+}
+
+Real
+Spring_description::length (Real f) const
+{
+ return ideal_ + max (f, block_force_) * inverse_hooke_;
+}
+
+/****************************************************************/
+
+/*
+ TODO: should a add penalty for widely varying spring forces (caused
+ by constraints, eg.
+
+
+ . =====
+ . | |
+ .o|o|x ##x
+ .
+
+ The ## forces the notes apart; we shouldn't allow the O's to touch
+ this closely.
+*/
+
+struct Rod_description
+{
+ vsize r_;
+ Real dist_;
+
+ bool operator< (const Rod_description r)
+ {
+ return r_ < r.r_;
+ }
+
+ Rod_description ()
+ {
+ r_ = 0;
+ dist_ = 0;
+ }
+
+ Rod_description (vsize r, Real d)
+ {
+ r_ = r;
+ dist_ = d;
+ }
+};
+
+struct Column_description
+{
+ vector<Rod_description> rods_;
+ vector<Rod_description> end_rods_; /* use these if they end at the last column of the line */
+ Real ideal_;
+ Real inverse_hooke_;
+ Real end_ideal_;
+ Real end_inverse_hooke_;
+ SCM break_permission_;
+ Interval keep_inside_line_;
+
+ Column_description ()
+ {
+ ideal_ = 0;
+ inverse_hooke_ = 0;
+ end_ideal_ = 0;
+ end_inverse_hooke_ = 0;
+ break_permission_ = SCM_EOL;
+ }
+};
+
+static int compare_paper_column_rank (Grob *const &a, Grob *const &b);
+
+static bool
+is_loose (Grob *g)
+{
+ return (scm_is_pair (g->get_object ("between-cols")));
+}
+
+static Grob*
+maybe_find_prebroken_piece (Grob *g, Direction d)
+{
+ Grob *ret = dynamic_cast<Item*> (g)->find_prebroken_piece (d);
+ if (ret)
+ return ret;
+ return g;
+}
+
+static Grob*
+next_spaceable_column (vector<Grob*> const &list, vsize starting)
+{
+ for (vsize i = starting+1; i < list.size (); i++)
+ if (!is_loose (list[i]))
+ return list[i];
+ return 0;
+}
+
+/* this only returns non-NULL if the line-ending column is the next
+ spaceable-or-breakable column */
+static Grob*
+next_line_ending_column (vector<Grob*> const &list, vsize starting)
+{
+ vsize i = starting + 1;
+ for (; i < list.size ()
+ && is_loose (list[i])
+ && !Paper_column::is_breakable (list[i]);
+ i++)
+ ;
+ return dynamic_cast<Item*> (list[i])->find_prebroken_piece (LEFT);
+}
+
+static void
+get_column_spring (Grob *this_col, Grob *next_col, Real *ideal, Real *inv_hooke)
+{
+ Spring_smob *spring = 0;
+
+ for (SCM s = this_col->get_object ("ideal-distances");
+ !spring && scm_is_pair (s);
+ s = scm_cdr (s))
+ {
+ Spring_smob *sp = unsmob_spring (scm_car (s));
+
+ if (sp->other_ == next_col)
+ spring = sp;
+ }
+
+ if (!spring)
+ programming_error (_f ("No spring between column %d and next one",
+ Paper_column::get_rank (this_col)));
+
+ *ideal = (spring) ? spring->distance_ : 5.0;
+ *inv_hooke = (spring) ? spring->inverse_strength_ : 1.0;
+}
+
+static Column_description
+get_column_description (vector<Grob*> const &cols, vsize col_index, bool line_starter)
+{
+ Grob *col = cols[col_index];
+ if (line_starter)
+ col = maybe_find_prebroken_piece (col, RIGHT);
+
+ Column_description description;
+ Grob *next_col = next_spaceable_column (cols, col_index);
+ if (next_col)
+ get_column_spring (col, next_col, &description.ideal_, &description.inverse_hooke_);
+ Grob *end_col = next_line_ending_column (cols, col_index);
+ if (end_col)
+ get_column_spring (col, end_col, &description.end_ideal_, &description.end_inverse_hooke_);
+
+ for (SCM s = Spaceable_grob::get_minimum_distances (col);
+ scm_is_pair (s); s = scm_cdr (s))
+ {
+ Grob *other = unsmob_grob (scm_caar (s));
+ vsize j = binary_search (cols, other, &compare_paper_column_rank, col_index);
+ if (j != VPOS)
+ {
+ if (cols[j] == other)
+ description.rods_.push_back (Rod_description (j, scm_to_double (scm_cdar (s))));
+ else /* it must end at the LEFT prebroken_piece */
+ description.end_rods_.push_back (Rod_description (j, scm_to_double (scm_cdar (s))));
+ }
+ }
+ if (!line_starter && to_boolean (col->get_property ("keep-inside-line")))
+ description.keep_inside_line_ = col->extent (col, X_AXIS);
+ description.break_permission_ = col->get_property ("line-break-permission");
+ return description;
+}
+
+vector<Real>
+get_line_forces (vector<Grob*> const &icols, vector<vsize> breaks,
+ Real line_len, Real indent, bool ragged)
+{
+ vector<Real> force;
+ force.resize (breaks.size () * breaks.size (), infinity_f);
+
+ vector<Column_description> cols;
+ vsize b = 1;
+ SCM force_break = ly_symbol2scm ("force");
+
+ cols.push_back (Column_description ());
+ for (vsize i = 1; i < icols.size () - 1; i++)
+ {
+ if (b < breaks.size () && breaks[b] == i)
+ {
+ breaks[b] = cols.size ();
+ b++;
+ }
+ if (!is_loose (icols[i]))
+ cols.push_back (get_column_description (icols, i, false));
+ }
+ breaks.back () = cols.size () - 1;
+
+ for (vsize b = 0; b < breaks.size () - 1; b++)
+ {
+ cols[breaks[b]] = get_column_description (icols, breaks[b], true);
+ vsize st = breaks[b];
+
+ for (vsize c = b+1; c < breaks.size (); c++)
+ {
+ vsize end = breaks[c];
+ Simple_spacer spacer;
+
+ for (vsize i = breaks[b]; i < end - 1; i++)
+ spacer.add_spring (cols[i].ideal_, cols[i].inverse_hooke_);
+ spacer.add_spring (cols[end-1].end_ideal_, cols[end-1].inverse_hooke_);
+
+
+ for (vsize i = breaks[b]; i < end; i++)
+ {
+ for (vsize r = 0; r < cols[i].rods_.size (); r++)
+ if (cols[i].rods_[r].r_ < end)
+ spacer.add_rod (i - st, cols[i].rods_[r].r_ - st, cols[i].rods_[r].dist_);
+ for (vsize r = 0; r < cols[i].end_rods_.size (); r++)
+ if (cols[i].end_rods_[r].r_ == end)
+ spacer.add_rod (i - st, end - st, cols[i].end_rods_[r].dist_);
+ if (!cols[i].keep_inside_line_.is_empty ())
+ {
+ spacer.add_rod (i - st, end - st, cols[i].keep_inside_line_[RIGHT]);
+ spacer.add_rod (0, i - st, cols[i].keep_inside_line_[LEFT]);
+ }
+ }
+ spacer.solve ((b == 0) ? line_len - indent : line_len, ragged);
+ force[b * breaks.size () + c] = spacer.force ();
+
+ if (cols[end].break_permission_ == force_break)
+ break;
+ if (!spacer.fits ())
+ {
+ force[b * breaks.size () + c] = infinity_f;
+ break;
+ }
+ }
+ }
+ return force;
+}
+
+Column_x_positions
+get_line_configuration (vector<Grob*>const &columns,
+ Real line_len,
+ Real indent,
+ bool ragged)
+{
+ vector<Column_description> cols;
+ Simple_spacer spacer;
+ Column_x_positions ret;
+
+ ret.cols_.push_back (dynamic_cast<Item*> (columns[0])->find_prebroken_piece (RIGHT));
+ for (vsize i = 1; i < columns.size () - 1; i++)
+ {
+ if (is_loose (columns[i]))
+ ret.loose_cols_.push_back (columns[i]);
+ else
+ ret.cols_.push_back (columns[i]);
+ }
+ ret.cols_.push_back (dynamic_cast<Item*> (columns.back ())->find_prebroken_piece (LEFT));
+
+ cols.resize (ret.cols_.size () - 1);
+
+ /* since we've already put our line-ending column in the column list, we can ignore
+ the end_XXX_ fields of our column_description */
+ for (vsize i = 0; i < cols.size (); i++)
+ {
+ cols[i] = get_column_description (ret.cols_, i, i == 0);
+ spacer.add_spring (cols[i].ideal_, cols[i].inverse_hooke_);
+ }
+ for (vsize i = 0; i < cols.size (); i++)
+ {
+ for (vsize r = 0; r < cols[i].rods_.size (); r++)
+ spacer.add_rod (i, cols[i].rods_[r].r_, cols[i].rods_[r].dist_);
+ if (!cols[i].keep_inside_line_.is_empty ())
+ {
+ spacer.add_rod (i, cols.size (), cols[i].keep_inside_line_[RIGHT]);
+ spacer.add_rod (0, i, cols[i].keep_inside_line_[LEFT]);
+ }
+ }
+
+ spacer.solve (line_len, ragged);
+ ret.force_ = spacer.force ();
+
+ /*
+ We used to have a penalty for compression, no matter what, but that
+ fucked up wtk1-fugue2 (taking 3 full pages.)
+ */
+ ret.config_ = spacer.spring_positions ();
+ for (vsize i = 0; i < ret.config_.size (); i++)
+ ret.config_[i] += indent;
+
+ ret.satisfies_constraints_ = spacer.fits ();
+
+ /*
+ Check if breaking constraints are met.
+ */
+ for (vsize i = 1; i < ret.cols_.size () - 1; i++)
+ {
+ SCM p = ret.cols_[i]->get_property ("line-break-permission");
+ if (p == ly_symbol2scm ("force"))
+ ret.satisfies_constraints_ = false;
+ }
+
+ return ret;
+}
+static int
+compare_paper_column_rank (Grob *const &a,
+ Grob *const &b)
+{
+ return Paper_column::get_rank (a) - Paper_column::get_rank (b);
+}
projects / lilypond.git / blobdiff