lily/line-interface.cc

   1 /*
   2 line-interface.cc --  implement Line_interface
   3
   4 source file of the GNU LilyPond music typesetter
   5
   6 (c) 2004 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7
   8  */
   9
  10 #include "line-interface.hh"
  11 #include "stencil.hh"
  12 #include "grob.hh"
  13 #include "staff-symbol-referencer.hh"
  14 #include "lookup.hh"
  15 #include "paper-def.hh"
  16
  17
  18 Stencil
  19 Line_interface::make_dashed_line (Real thick, Offset from, Offset to,
  20                              Real dash_period, Real dash_fraction)
  21 {
  22   dash_fraction = (dash_fraction >? 0) <? 1.0;
  23   Real on = dash_fraction * dash_period + thick;
  24   Real off = dash_period - on;
  25
  26   SCM at = scm_list_n (ly_symbol2scm ("dashed-line"),
  27                         gh_double2scm (thick),
  28                         gh_double2scm (on),
  29                         gh_double2scm (off),
  30                         gh_double2scm (to[X_AXIS] - from[X_AXIS]),
  31                         gh_double2scm (to[Y_AXIS] - from[Y_AXIS]),
  32                         SCM_UNDEFINED);
  33
  34   Box box;
  35   box.add_point (Offset (0,0));
  36   box.add_point (to - from);
  37
  38   box[X_AXIS].widen (thick/2);
  39   box[Y_AXIS].widen (thick/2);
  40
  41   Stencil m = Stencil (box, at);
  42   m.translate (from);
  43   return m;
  44 }
  45
  46 Stencil
  47 Line_interface::make_line (Real th, Offset from, Offset to)
  48 {
  49   SCM at = scm_list_n (ly_symbol2scm ("draw-line"),
  50                         gh_double2scm (th),
  51                         gh_double2scm (from[X_AXIS]),
  52                         gh_double2scm (from[Y_AXIS]),
  53                         gh_double2scm (to[X_AXIS]),
  54                         gh_double2scm (to[Y_AXIS]),
  55                         SCM_UNDEFINED);
  56
  57   Box box;
  58   box.add_point (from);
  59   box.add_point (to);
  60
  61   box[X_AXIS].widen (th/2);
  62   box[Y_AXIS].widen (th/2);
  63
  64   return Stencil (box, at);
  65 }
  66
  67 Stencil
  68 Line_interface::line (Grob *me, Offset from, Offset to)
  69 {
  70   Real thick = Staff_symbol_referencer::line_thickness (me)
  71     * robust_scm2double (me->get_property ("thickness"),1);
  72
  73   SCM type = me->get_property ("style");
  74
  75   SCM dash_fraction = me->get_property ("dash-fraction");
  76   if (gh_number_p (dash_fraction) || type == ly_symbol2scm ("dotted-line"))
  77     {
  78
  79       Real fraction
  80         = type == ly_symbol2scm ("dotted-line")
  81         ? 0.0
  82         : robust_scm2double (dash_fraction, 0.4);
  83
  84       fraction = (fraction >? 0) <? 1.0;
  85       Real period = Staff_symbol_referencer::staff_space (me)
  86         * robust_scm2double (me->get_property ("dash-period"), 1.0);
  87
  88       if (period < 0)
  89         return Stencil ();
  90
  91       return make_dashed_line (thick, from, to, period, fraction);
  92     }
  93   else
  94     {
  95       return make_line (thick, from, to);
  96     }
  97 }
  98
  99 ADD_INTERFACE (Line_interface, "line-interface",
 100               "Generic line objects. Any object using lines supports this.  Normally,"
 101               "you get a straight line. If @code{dash-period} is defined, a dashed line is "
 102               "produced; the length of the dashes is tuned with "
 103               "@code{dash-fraction}. If the latter is set to 0, a dotted line is "
 104               "produced. If @code{dash-fraction} is negative, the line is made "
 105               "transparent.",
 106
 107               "dash-period dash-fraction thickness style")