lily/bar-engraver.cc

   1 /*
   2   bar-engraver.cc -- implement Bar_engraver
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1997--2005 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7   Jan Nieuwenhuizen <janneke@gnu.org>
   8 */
   9
  10 #include "bar-line.hh"
  11 #include "score-engraver.hh"
  12 #include "warn.hh"
  13 #include "item.hh"
  14
  15 /*
  16   generate bars. Either user ("|:"), or default (new measure)
  17 */
  18 class Bar_engraver : public Engraver
  19 {
  20 public:
  21   TRANSLATOR_DECLARATIONS (Bar_engraver);
  22   void request_bar (String type_string);
  23
  24 protected:
  25   virtual void finalize ();
  26   virtual void stop_translation_timestep ();
  27   virtual void process_acknowledged_grobs ();
  28
  29 private:
  30   void typeset_bar ();
  31   void create_bar ();
  32
  33   Item *bar_;
  34 };
  35
  36 Bar_engraver::Bar_engraver ()
  37 {
  38   bar_ = 0;
  39 }
  40
  41 void
  42 Bar_engraver::create_bar ()
  43 {
  44   if (!bar_)
  45     {
  46       bar_ = make_item ("BarLine", SCM_EOL);
  47       SCM gl = get_property ("whichBar");
  48       if (scm_equal_p (gl, bar_->get_property ("glyph")) != SCM_BOOL_T)
  49         bar_->set_property ("glyph", gl);
  50     }
  51 }
  52
  53 void
  54 Bar_engraver::finalize ()
  55 {
  56   typeset_bar ();
  57 }
  58
  59 /*
  60   Bar_engraver should come *after* any engravers that
  61   modify whichBar
  62
  63   This is a little hairy : whichBar may be set by
  64   Repeat_acknowledge_engraver::process_music, which is at score
  65   context. This means that grobs could should be created after
  66   process_music. We do stuff process_acknowledged_grobs (), just to be
  67   on the safe side.
  68 */
  69
  70 void
  71 Bar_engraver::process_acknowledged_grobs ()
  72 {
  73   if (!bar_ && scm_is_string (get_property ("whichBar")))
  74     create_bar ();
  75 }
  76
  77 void
  78 Bar_engraver::typeset_bar ()
  79 {
  80   bar_ = 0;
  81 }
  82
  83 /*
  84   lines may only be broken if there is a barline in all staves
  85 */
  86 void
  87 Bar_engraver::stop_translation_timestep ()
  88 {
  89   if (!bar_)
  90     /* guh. Use properties! */
  91     get_score_engraver ()->forbid_breaks ();
  92   else
  93     typeset_bar ();
  94 }
  95
  96 ADD_TRANSLATOR (Bar_engraver,
  97                 /* descr */ "Create barlines. This engraver is controlled through the "
  98                 "@code{whichBar} property. If it has no bar line to create, it will forbid a linebreak at this point",
  99                 /* creats*/ "BarLine",
 100                 /* accepts */ "",
 101                 /* acks  */ "",
 102                 /* reads */ "whichBar",
 103                 /* write */ "");