+/*
+ timing-engraver.cc -- implement Default_bar_line_engraver
+
+ source file of the GNU LilyPond music typesetter
+
+ (c) 1997--2005 Han-Wen Nienhuys <hanwen@cs.uu.nl>
+*/
+
+#include "engraver.hh"
+#include "context.hh"
+#include "multi-measure-rest.hh"
+#include "grob.hh"
+#include "warn.hh"
+
+
+class Default_bar_line_engraver : public Engraver
+{
+protected:
+ /* Need to know whether we're advancing in grace notes, or not. */
+ Moment last_moment_;
+
+ PRECOMPUTED_VIRTUAL void start_translation_timestep ();
+ PRECOMPUTED_VIRTUAL void stop_translation_timestep ();
+
+public:
+ TRANSLATOR_DECLARATIONS (Default_bar_line_engraver);
+};
+
+#include "translator.icc"
+
+ADD_TRANSLATOR (Default_bar_line_engraver,
+ "This engraver determines what kind of automatic bar lines should be produced, "
+ "and sets @code{whichBar} accordingly. It should be at the same "
+ "level as @ref{Timing_translator}. ",
+ /* creats*/ "",
+ /* accepts */ "",
+ /* acks */ "",
+ /* reads */
+ "measurePosition automaticBars whichBar barAlways defaultBarType "
+ "measureLength",
+ /* write */ "automaticBars");
+
+
+Default_bar_line_engraver::Default_bar_line_engraver ()
+{
+ last_moment_.main_part_ = Rational (-1);
+}
+
+void
+Default_bar_line_engraver::start_translation_timestep ()
+{
+ SCM automatic_bars = get_property ("automaticBars");
+ Moment now = now_mom ();
+ SCM which = get_property ("whichBar");
+
+ /* Set the first bar of the score? */
+ if (!scm_is_string (which))
+ which = SCM_EOL;
+
+ Moment mp = measure_position (context ());
+ bool start_of_measure = (last_moment_.main_part_ != now.main_part_
+ && !mp.main_part_);
+
+ if (!scm_is_string (which) && to_boolean (automatic_bars))
+ {
+ SCM always = get_property ("barAlways");
+
+ if ((start_of_measure && last_moment_.main_part_ >= Moment (0))
+ || to_boolean (always))
+ {
+ /* should this work, or be junked? See input/bugs/no-bars.ly */
+ which = get_property ("defaultBarType");
+ }
+ }
+
+ context ()->set_property ("whichBar", which);
+}
+
+void
+Default_bar_line_engraver::stop_translation_timestep ()
+{
+ context ()->set_property ("whichBar", SCM_EOL);
+ last_moment_ = now_mom ();
+}