lily/line-interface.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 2004--2011 Han-Wen Nienhuys <hanwen@xs4all.nl>
   5
   6   LilyPond is free software: you can redistribute it and/or modify
   7   it under the terms of the GNU General Public License as published by
   8   the Free Software Foundation, either version 3 of the License, or
   9   (at your option) any later version.
  10
  11   LilyPond is distributed in the hope that it will be useful,
  12   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14   GNU General Public License for more details.
  15
  16   You should have received a copy of the GNU General Public License
  17   along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "line-interface.hh"
  21
  22 #include "font-interface.hh"
  23 #include "grob.hh"
  24 #include "lookup.hh"
  25 #include "output-def.hh"
  26 #include "staff-symbol-referencer.hh"
  27
  28 Stencil
  29 Line_interface::make_arrow (Offset begin, Offset end,
  30                             Real thick,
  31                             Real length, Real width)
  32 {
  33   Real angle = (end - begin).arg ();
  34   vector<Offset> points;
  35
  36   points.push_back (Offset (0, 0));
  37   points.push_back (Offset (-length, width));
  38   points.push_back (Offset (-length, -width));
  39
  40   for (vsize i = 0; i < points.size (); i++)
  41     points[i] = points[i] * complex_exp (Offset (0, angle)) + end;
  42
  43   return Lookup::round_filled_polygon (points, thick);
  44 }
  45
  46 Stencil
  47 Line_interface::make_trill_line (Grob *me,
  48                                  Offset from,
  49                                  Offset to)
  50 {
  51   Offset dz = (to - from);
  52
  53   Font_metric *fm = Font_interface::get_default_font (me);
  54
  55   Stencil elt = fm->find_by_name ("scripts.trill_element");
  56   elt.align_to (Y_AXIS, CENTER);
  57   Real elt_len = elt.extent (X_AXIS).length ();
  58   if (elt_len <= 0.0)
  59     {
  60       programming_error ("can't find scripts.trill_element");
  61       return Stencil ();
  62     }
  63
  64   Stencil line;
  65   Real len = 0.0;
  66   do
  67     {
  68       line.add_at_edge (X_AXIS, RIGHT, elt, 0);
  69       len = line.extent (X_AXIS).length ();
  70     }
  71   while (len + elt_len < dz.length ());
  72
  73   line.rotate (dz.arg (), Offset (LEFT, CENTER));
  74   line.translate (from);
  75
  76   return line;
  77 }
  78
  79
  80 Stencil
  81 Line_interface::make_zigzag_line (Grob *me,
  82                                   Offset from,
  83                                   Offset to)
  84 {
  85   Offset dz = to - from;
  86
  87   Real thick = Staff_symbol_referencer::line_thickness (me);
  88   thick *= robust_scm2double (me->get_property ("thickness"), 1.0); // todo: staff sym referencer?
  89
  90   Real staff_space = Staff_symbol_referencer::staff_space (me);
  91
  92   Real w = robust_scm2double (me->get_property ("zigzag-width"), 1) * staff_space;
  93   int count = (int) ceil (dz.length () / w);
  94   w = dz.length () / count;
  95
  96   Real l = robust_scm2double (me->get_property ("zigzag-length"), 1) * w;
  97   Real h = l > w / 2 ? sqrt (l * l - w * w / 4) : 0;
  98
  99   Offset rotation_factor = complex_exp (Offset (0, dz.arg ()));
 100
 101   Offset points[3];
 102   points[0] = Offset (0, -h / 2);
 103   points[1] = Offset (w / 2, h / 2);
 104   points[2] = Offset (w, -h / 2);
 105   for (int i = 0; i < 3; i++)
 106     points[i] = complex_multiply (points[i], rotation_factor);
 107
 108   Stencil squiggle (Line_interface::make_line (thick, points[0], points[1]));
 109   squiggle.add_stencil (Line_interface::make_line (thick, points[1], points[2]));
 110
 111   Stencil total;
 112   for (int i = 0; i < count; i++)
 113     {
 114       Stencil moved_squiggle (squiggle);
 115       moved_squiggle.translate (from + Offset (i * w, 0) * rotation_factor);
 116       total.add_stencil (moved_squiggle);
 117     }
 118
 119   return total;
 120 }
 121
 122
 123 Stencil
 124 Line_interface::make_dashed_line (Real thick, Offset from, Offset to,
 125                                   Real dash_period, Real dash_fraction)
 126 {
 127   dash_fraction = min (max (dash_fraction, 0.0), 1.0);
 128   Real on = dash_fraction * dash_period + thick;
 129   Real off = max (0.0, dash_period - on);
 130
 131   SCM at = scm_list_n (ly_symbol2scm ("dashed-line"),
 132                        scm_from_double (thick),
 133                        scm_from_double (on),
 134                        scm_from_double (off),
 135                        scm_from_double (to[X_AXIS] - from[X_AXIS]),
 136                        scm_from_double (to[Y_AXIS] - from[Y_AXIS]),
 137                        scm_from_double (0.0),
 138                        SCM_UNDEFINED);
 139
 140   Box box;
 141   box.add_point (Offset (0, 0));
 142   box.add_point (to - from);
 143
 144   box[X_AXIS].widen (thick / 2);
 145   box[Y_AXIS].widen (thick / 2);
 146
 147   Stencil m = Stencil (box, at);
 148   m.translate (from);
 149   return m;
 150 }
 151
 152 Stencil
 153 Line_interface::make_line (Real th, Offset from, Offset to)
 154 {
 155   SCM at = scm_list_n (ly_symbol2scm ("draw-line"),
 156                        scm_from_double (th),
 157                        scm_from_double (from[X_AXIS]),
 158                        scm_from_double (from[Y_AXIS]),
 159                        scm_from_double (to[X_AXIS]),
 160                        scm_from_double (to[Y_AXIS]),
 161                        SCM_UNDEFINED);
 162
 163   Box box;
 164   box.add_point (from);
 165   box.add_point (to);
 166
 167   box[X_AXIS].widen (th / 2);
 168   box[Y_AXIS].widen (th / 2);
 169
 170   return Stencil (box, at);
 171 }
 172
 173 Stencil
 174 Line_interface::arrows (Grob *me, Offset from, Offset to,
 175                         bool from_arrow,
 176                         bool to_arrow)
 177 {
 178   Stencil a;
 179   if (from_arrow || to_arrow)
 180     {
 181       Real thick = Staff_symbol_referencer::line_thickness (me)
 182         * robust_scm2double (me->get_property ("thickness"), 1);
 183       Real ss = Staff_symbol_referencer::staff_space (me);
 184
 185       Real len = robust_scm2double (me->get_property ("arrow-length"), 1.3 * ss);
 186       Real wid = robust_scm2double (me->get_property ("arrow-width"), 0.5 * ss);
 187
 188       if (to_arrow)
 189         a.add_stencil (make_arrow (from, to, thick, len, wid));
 190
 191       if (from_arrow)
 192         a.add_stencil (make_arrow (to, from, thick, len, wid));
 193     }
 194
 195   return a;
 196 }
 197
 198 Stencil
 199 Line_interface::line (Grob *me, Offset from, Offset to)
 200 {
 201   Real thick = Staff_symbol_referencer::line_thickness (me)
 202     * robust_scm2double (me->get_property ("thickness"), 1);
 203
 204   SCM type = me->get_property ("style");
 205   if (type == ly_symbol2scm ("zigzag"))
 206     return make_zigzag_line (me, from, to);
 207   else if (type == ly_symbol2scm ("trill"))
 208     return make_trill_line (me, from, to);
 209   else if (type == ly_symbol2scm ("none"))
 210     return Stencil ();
 211
 212   Stencil stencil;
 213
 214   if (type == ly_symbol2scm ("dashed-line") || type == ly_symbol2scm ("dotted-line"))
 215     {
 216
 217       Real fraction
 218         = type == ly_symbol2scm ("dotted-line")
 219         ? 0.0
 220         : robust_scm2double (me->get_property ("dash-fraction"), 0.4);
 221
 222       fraction = min (max (fraction, 0.0), 1.0);
 223       Real period = Staff_symbol_referencer::staff_space (me)
 224         * robust_scm2double (me->get_property ("dash-period"), 1.0);
 225
 226       if (period <= 0)
 227         return Stencil ();
 228
 229       Real len = (to - from).length ();
 230
 231       int n = (int) rint ((len - period * fraction) / period);
 232       n = max (0, n);
 233       if (n > 0)
 234         {
 235           /*
 236             TODO: figure out something intelligent for really short
 237             sections.
 238            */
 239           period = ((to - from).length () - period * fraction) / n;
 240         }
 241       stencil = make_dashed_line (thick, from, to, period, fraction);
 242     }
 243   else
 244     stencil = make_line (thick, from, to);
 245
 246   return stencil;
 247 }
 248
 249 ADD_INTERFACE (Line_interface,
 250                "Generic line objects.  Any object using lines supports this."
 251                "  The property @code{style} can be @code{line},"
 252                " @code{dashed-line}, @code{trill}, @code{dotted-line},"
 253                " @code{zigzag} or @code{none} (a transparent line).\n"
 254                "\n"
 255                "For @code{dashed-line}, the length of the dashes is tuned"
 256                " with @code{dash-fraction}.  If the latter is set to@tie{}0, a"
 257                " dotted line is produced.",
 258
 259                /* properties */
 260                "arrow-length "
 261                "arrow-width "
 262                "dash-fraction "
 263                "dash-period "
 264                "style "
 265                "thickness "
 266                "zigzag-length "
 267                "zigzag-width "
 268                );