lily/tex-beam.cc

   1 /*
   2   tex-beam.cc -- implement Lookup::{beam_element, beam, rule_symbol}
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1996,1997 Han-Wen Nienhuys <hanwen@stack.nl>
   7 */
   8
   9 /*
  10   Code to generate beams for TeX
  11   */
  12
  13 #include <math.h>
  14 #include "atom.hh"
  15 #include "molecule.hh"
  16 #include "tex.hh"
  17 #include "symtable.hh"
  18 #include "dimen.hh"
  19 #include "debug.hh"
  20 #include "lookup.hh"
  21 #include "misc.hh"
  22
  23 Atom
  24 Lookup::beam_element (int sidx, int widx, Real slope) const
  25 {
  26   String name = String("slope");
  27   Atom bs=(*symtables_)("beamslopes")->lookup (name);
  28
  29   Array<String> args;
  30   args.push (sidx);
  31   args.push (widx);
  32   bs.tex_ = substitute_args (bs.tex_,args);
  33   int w = 2 << widx;
  34   Real width = w PT;
  35   bs.dim_.x() = Interval (0,width);
  36   bs.dim_.y() = Interval (0,width*slope);
  37   return bs;
  38 }
  39
  40
  41 Atom
  42 Lookup::rule_symbol (Real height, Real width) const
  43 {
  44   Atom bs=(*symtables_)("beamslopes")->lookup ("horizontal");
  45   Array<String> args;
  46   args.push (print_dimen (height));
  47   args.push (print_dimen (width));
  48   bs.tex_ = substitute_args (bs.tex_,args);
  49   bs.dim_.x() = Interval (0,width);
  50   bs.dim_.y() = Interval (0,height);
  51   return bs;
  52 }
  53
  54 Atom
  55 Lookup::beam (Real &slope, Real width) const
  56 {
  57   int sidx = 0;
  58   if (abs (slope) > 1.0)
  59     {
  60       WARN << "beam steeper than 1.0 (" << slope << ")\n";
  61       slope = sign (slope);
  62     }
  63
  64   sidx = int (rint (slope *  20.0));
  65   slope = sidx / 20.0;
  66
  67   Interval xdims = (*symtables_)("beamslopes")->lookup ("slope").dim_[X_AXIS];
  68   Real min_wid = xdims[LEFT];
  69   Real max_wid = xdims[RIGHT];
  70   assert(max_wid > 0);
  71   int widths = intlog2 (int (max_wid/min_wid)) + 1;
  72
  73   if (width < min_wid)
  74     {
  75       WARN<<"Beam too narrow. (" << print_dimen (width) <<")\n";
  76       width = min_wid;
  77     }
  78
  79   Real elemwidth = max_wid;
  80
  81   int widx  =widths - 1;
  82   Molecule m;
  83   while (elemwidth > width)
  84     {
  85       widx --;
  86       elemwidth /= 2.0;
  87     }
  88   Real overlap = elemwidth/4;
  89   Real last_x = width - elemwidth;
  90   Real x = overlap;
  91   Atom elem (beam_element (sidx * widths, widx, slope));
  92   m.add (elem);
  93   while (x < last_x)
  94     {
  95       Atom a(elem);
  96       a.translate (Offset (x-overlap, (x-overlap)*slope));
  97       m.add (a);
  98       x += elemwidth - overlap;
  99     }
 100   Atom a(elem);
 101   a.translate (Offset (last_x, (last_x) * slope));
 102   m.add (a);
 103
 104   Atom ret;
 105   ret.tex_ = m.TeX_string();
 106   ret.dim_.y() = Interval (0,width*slope);
 107   ret.dim_.x() = Interval (0,width);
 108
 109   return ret;
 110 }
 111
 112