X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=lily%2Fgrob.cc;h=f11e52a4fc588bbc6e94a0059870508b6907acdf;hb=73e40a0dd515fd996ee0918dd96b42a754f623d5;hp=4077188023f22a9ab952a30d153a3a7bd3f82d84;hpb=8d7a55721e3305f745c0b24c367de002dd197825;p=lilypond.git diff --git a/lily/grob.cc b/lily/grob.cc index 4077188023..f11e52a4fc 100644 --- a/lily/grob.cc +++ b/lily/grob.cc @@ -12,21 +12,18 @@ #include "main.hh" #include "input-smob.hh" - +#include "warn.hh" #include "group-interface.hh" #include "misc.hh" #include "paper-score.hh" -#include "paper-def.hh" #include "molecule.hh" #include "grob.hh" -#include "debug.hh" +#include "warn.hh" #include "spanner.hh" -#include "line-of-score.hh" +#include "system.hh" #include "item.hh" -#include "paper-column.hh" #include "molecule.hh" #include "misc.hh" -#include "paper-outputter.hh" #include "music.hh" #include "item.hh" @@ -39,7 +36,8 @@ remove dynamic_cast and put this code into respective subclass. */ - +//#define HASHING_FOR_MUTABLE_PROPS +#define HASH_SIZE 3 #define INFINITY_MSG "Infinity or NaN encountered" Grob::Grob (SCM basicprops) @@ -47,15 +45,39 @@ Grob::Grob (SCM basicprops) /* fixme: default should be no callback. */ - - pscore_l_=0; - status_c_ = 0; - original_l_ = 0; + self_scm_ = SCM_EOL; + pscore_=0; + status_ = 0; + original_ = 0; immutable_property_alist_ = basicprops; mutable_property_alist_ = SCM_EOL; + /* + We do smobify_self() as the first step. Since the object lives on + the heap, none of its SCM variables are protected from GC. After + smobify_self(), they are. + */ smobify_self (); + +#ifdef HASHING_FOR_MUTABLE_PROPS + mutable_property_alist_ = scm_c_make_hash_table (HASH_SIZE); +#endif + + SCM meta = get_grob_property ("meta"); + if (gh_pair_p (meta)) + { + SCM ifs = scm_assoc (ly_symbol2scm ("interfaces"), meta); + + /* + Switch off interface checks for the moment. + */ + bool itc = internal_type_checking_global_b; + internal_type_checking_global_b = false; + internal_set_grob_property (ly_symbol2scm ("interfaces"), gh_cdr(ifs)); + internal_type_checking_global_b = itc; + } + /* TODO: @@ -85,32 +107,39 @@ Grob::Grob (SCM basicprops) /* Should change default to be empty? */ - if (cb != SCM_BOOL_F && !gh_procedure_p (cb) && !gh_pair_p (cb)) + if (cb != SCM_BOOL_F + && !gh_procedure_p (cb) && !gh_pair_p (cb) + && gh_procedure_p (get_grob_property ("molecule-callback")) + ) cb = molecule_extent_proc; dim_cache_[a].dimension_ = cb; } - SCM meta = get_grob_property ("meta"); - if (gh_pair_p (meta)) - { - SCM ifs = scm_assoc (ly_symbol2scm ("interfaces"), meta); - - set_grob_property ("interfaces",ly_cdr (ifs)); - } } Grob::Grob (Grob const&s) : dim_cache_ (s.dim_cache_) { - original_l_ = (Grob*) &s; + original_ = (Grob*) &s; + self_scm_ = SCM_EOL; + immutable_property_alist_ = s.immutable_property_alist_; + mutable_property_alist_ = SCM_EOL; - status_c_ = s.status_c_; - pscore_l_ = s.pscore_l_; + /* + No properties are copied. That is the job of handle_broken_dependencies. + */ + + status_ = s.status_; + pscore_ = s.pscore_; smobify_self (); + +#ifdef HASHING_FOR_MUTABLE_PROPS + mutable_property_alist_ = scm_c_make_hash_table (HASH_SIZE); +#endif } Grob::~Grob () @@ -121,64 +150,7 @@ Grob::~Grob () } -SCM -Grob::internal_get_grob_property (SCM sym) const -{ - SCM s = scm_sloppy_assq (sym, mutable_property_alist_); - if (s != SCM_BOOL_F) - return ly_cdr (s); - - s = scm_sloppy_assq (sym, immutable_property_alist_); - return (s == SCM_BOOL_F) ? SCM_EOL : ly_cdr (s); -} - -/* - Remove the value associated with KEY, and return it. The result is - that a next call will yield SCM_EOL (and not the underlying - `basic' property. -*/ -SCM -Grob::remove_grob_property (const char* key) -{ - SCM val = get_grob_property (key); - if (val != SCM_EOL) - set_grob_property (key, SCM_EOL); - return val; -} - - -#if 0 -/* - Puts the k, v in the immutable_property_alist_, which is convenient for - storing variables that are needed during the breaking process. (eg. - Line_of_score::rank : int) - */ -void -Grob::set_immutable_grob_property (const char*k, SCM v) -{ - SCM s = ly_symbol2scm (k); - set_immutable_grob_property (s, v); -} - -void -Grob::set_immutable_grob_property (SCM s, SCM v) -{ - immutable_property_alist_ = gh_cons (gh_cons (s,v), mutable_property_alist_); - mutable_property_alist_ = scm_assq_remove_x (mutable_property_alist_, s); -} -#endif - -void -Grob::internal_set_grob_property (SCM s, SCM v) -{ -#ifndef NDEBUG - if (internal_type_checking_global_b) - assert (type_check_assignment (s, v, ly_symbol2scm ("backend-type?"))); -#endif - - mutable_property_alist_ = scm_assq_set_x (mutable_property_alist_, s, v); -} MAKE_SCHEME_CALLBACK (Grob,molecule_extent,2); @@ -196,7 +168,6 @@ Grob::molecule_extent (SCM element_smob, SCM scm_axis) } MAKE_SCHEME_CALLBACK (Grob,preset_extent,2); - SCM Grob::preset_extent (SCM element_smob, SCM scm_axis) { @@ -204,8 +175,8 @@ Grob::preset_extent (SCM element_smob, SCM scm_axis) Axis a = (Axis) gh_scm2int (scm_axis); SCM ext = s->get_grob_property ((a == X_AXIS) - ? "extent-X" - : "extent-Y"); + ? "X-extent" + : "Y-extent"); if (gh_pair_p (ext)) { @@ -220,55 +191,64 @@ Grob::preset_extent (SCM element_smob, SCM scm_axis) Paper_def* -Grob::paper_l () const +Grob::get_paper () const { - return pscore_l_ ? pscore_l_->paper_l_ : 0; + return pscore_ ? pscore_->paper_ : 0; } void Grob::calculate_dependencies (int final, int busy, SCM funcname) { - if (status_c_ >= final) + if (status_ >= final) return; - if (status_c_== busy) + if (status_== busy) { programming_error ("Element is busy, come back later"); return; } - status_c_= busy; + status_= busy; - for (SCM d= get_grob_property ("dependencies"); gh_pair_p (d); d = ly_cdr (d)) + for (SCM d = get_grob_property ("dependencies"); gh_pair_p (d); + d = ly_cdr (d)) { unsmob_grob (ly_car (d)) ->calculate_dependencies (final, busy, funcname); } - // ughugh. - String s = ly_symbol2string (funcname); - SCM proc = get_grob_property (s.ch_C ()); + + SCM proc = internal_get_grob_property (funcname); if (gh_procedure_p (proc)) gh_call1 (proc, this->self_scm ()); - - status_c_= final; - + + status_= final; } Molecule * Grob::get_molecule () const { + if (!live()) + { + return 0; + + } + SCM mol = get_grob_property ("molecule"); if (unsmob_molecule (mol)) return unsmob_molecule (mol); mol = get_uncached_molecule (); - Grob *me = (Grob*)this; - me->set_grob_property ("molecule", mol); + if (live ()) + { + Grob *me = (Grob*)this; + me->set_grob_property ("molecule", mol); + } return unsmob_molecule (mol); } + SCM Grob::get_uncached_molecule ()const { @@ -277,22 +257,22 @@ Grob::get_uncached_molecule ()const SCM mol = SCM_EOL; if (gh_procedure_p (proc)) mol = gh_apply (proc, scm_list_n (this->self_scm (), SCM_UNDEFINED)); - Molecule *m = unsmob_molecule (mol); if (unsmob_molecule (mol)) { - SCM origin = ly_symbol2scm ("no-origin"); + SCM origin = ly_symbol2scm ("no-origin"); - if (store_locations_global_b){ - SCM cause = get_grob_property ("cause"); - if (Music*m = unsmob_music (cause)) - { - SCM music_origin = m->get_mus_property ("origin"); - if (unsmob_input (music_origin)) - origin = music_origin; - } + if (store_locations_global_b) + { + SCM cause = get_grob_property ("cause"); + if (Music*m = unsmob_music (cause)) + { + SCM music_origin = m->get_mus_property ("origin"); + if (unsmob_input (music_origin)) + origin = music_origin; + } } // ugr. @@ -323,13 +303,8 @@ Grob::do_break_processing () { } - - - - - -Line_of_score * -Grob::line_l () const +System * +Grob::get_system () const { return 0; } @@ -346,129 +321,35 @@ Grob::add_dependency (Grob*e) } - - -/** - Do break substitution in S, using CRITERION. Return new value. - CRITERION is either a SMOB pointer to the desired line, or a number - representing the break direction. Do not modify SRC. - - It is rather tightly coded, since it takes a lot of time; it is - one of the top functions in the profile. - -*/ -SCM -Grob::handle_broken_grobs (SCM src, SCM criterion) -{ - again: - Grob *sc = unsmob_grob (src); - if (sc) - { - if (SCM_INUMP (criterion)) - { - Item * i = dynamic_cast (sc); - Direction d = to_dir (criterion); - if (i && i->break_status_dir () != d) - { - Item *br = i->find_prebroken_piece (d); - return (br) ? br->self_scm () : SCM_UNDEFINED; - } - } - else - { - Line_of_score * line - = dynamic_cast (unsmob_grob (criterion)); - if (sc->line_l () != line) - { - sc = sc->find_broken_piece (line); - - } - - /* now: !sc || (sc && sc->line_l () == line) */ - if (!sc) - return SCM_UNDEFINED; - - /* now: sc && sc->line_l () == line */ - if (!line) - return sc->self_scm(); - /* - This was introduced in 1.3.49 as a measure to prevent - programming errors. It looks expensive (?). TODO: - benchmark , document when (what kind of programming - errors) this happens. - */ - if (sc->common_refpoint (line, X_AXIS) - && sc->common_refpoint (line, Y_AXIS)) - { - return sc->self_scm (); - } - return SCM_UNDEFINED; - } - } - else if (ly_pair_p (src)) // SCM_CONSP (src)) // huh? - { - SCM oldcar =ly_car (src); - /* - UGH! breaks on circular lists. - */ - SCM newcar = handle_broken_grobs (oldcar, criterion); - SCM oldcdr = ly_cdr (src); - - if (newcar == SCM_UNDEFINED - && (gh_pair_p (oldcdr) || oldcdr == SCM_EOL)) - { - /* - This is tail-recursion, ie. - - return handle_broken_grobs (cdr, criterion); - - We don't want to rely on the compiler to do this. Without - tail-recursion, this easily crashes with a stack overflow. */ - src = oldcdr; - goto again; - } - - SCM newcdr = handle_broken_grobs (oldcdr, criterion); - return scm_cons (newcar, newcdr); - } - else - return src; - - return src; -} - void Grob::handle_broken_dependencies () { - Spanner * s= dynamic_cast (this); - if (original_l_ && s) + Spanner * sp = dynamic_cast (this); + if (original_ && sp) return; - if (s) + if (sp) { - for (int i = 0; i< s->broken_into_l_arr_ .size (); i++) + for (SCM s = mutable_property_alist_; gh_pair_p(s); + s = gh_cdr(s)) { - Grob * sc = s->broken_into_l_arr_[i]; - Line_of_score * l = sc->line_l (); - sc->mutable_property_alist_ = - handle_broken_grobs (mutable_property_alist_, - l ? l->self_scm () : SCM_UNDEFINED); + sp->substitute_one_mutable_property (gh_caar (s), + gh_cdar (s)); + } } + System *system = get_system (); - Line_of_score *line = line_l (); - - if (line && common_refpoint (line, X_AXIS) && common_refpoint (line, Y_AXIS)) + if (live () + && system && common_refpoint (system, X_AXIS) && common_refpoint (system, Y_AXIS)) { - mutable_property_alist_ - = handle_broken_grobs (mutable_property_alist_, - line ? line->self_scm () : SCM_UNDEFINED); + substitute_mutable_properties (system ? system->self_scm () : SCM_UNDEFINED, + mutable_property_alist_); } - else if (dynamic_cast (this)) + else if (dynamic_cast (this)) { - mutable_property_alist_ = handle_broken_grobs (mutable_property_alist_, - SCM_UNDEFINED); + substitute_mutable_properties (SCM_UNDEFINED, mutable_property_alist_); } else { @@ -476,9 +357,10 @@ Grob::handle_broken_dependencies () This element is `invalid'; it has been removed from all dependencies, so let's junk the element itself. - do not do this for Line_of_score, since that would remove - references to the originals of score-elts, which get then GC'd - (a bad thing.) + do not do this for System, since that would remove references + to the originals of score-grobs, which get then GC'd (a bad + thing.) + */ suicide (); } @@ -492,30 +374,63 @@ Grob::handle_broken_dependencies () void Grob::suicide () { + if (!live ()) + return; + +#if 0 // see below. + String nm = name(); +#endif + mutable_property_alist_ = SCM_EOL; immutable_property_alist_ = SCM_EOL; - set_extent_callback (SCM_EOL, Y_AXIS); - set_extent_callback (SCM_EOL, X_AXIS); + set_extent (SCM_EOL, Y_AXIS); + set_extent (SCM_EOL, X_AXIS); for (int a= X_AXIS; a <= Y_AXIS; a++) { dim_cache_[a].offset_callbacks_ = SCM_EOL; dim_cache_[a].offsets_left_ = 0; } + +#if 0 + /* + This can make debugging a little easier: we can still know what + the object used to be. However, since all its links have been + broken, it's usually more convenient to set a conditional + breakpoint in GDB before the property lists are wiped. + */ + mutable_property_alist_ = scm_acons (ly_symbol2scm ("name"), + scm_makfrom0str (nm.to_str0()), + mutable_property_alist_ + ); +#endif } void Grob::handle_prebroken_dependencies () { + /* + Don't do this in the derived method, since we want to keep access to + mutable_property_alist_ centralized. + */ + if (original_) + { + Item * it = dynamic_cast (this); + substitute_mutable_properties (gh_int2scm (it->break_status_dir ()), + original_->mutable_property_alist_); + } } Grob* -Grob::find_broken_piece (Line_of_score*) const +Grob::find_broken_piece (System*) const { return 0; } +/* + translate in one direction +*/ void Grob::translate_axis (Real y, Axis a) { @@ -527,6 +442,13 @@ Grob::translate_axis (Real y, Axis a) } } + +/* + Find the offset relative to D. If D equals THIS, then it is 0. + Otherwise, it recursively defd as + + OFFSET_ + PARENT_L_->relative_coordinate (D) +*/ Real Grob::relative_coordinate (Grob const*refp, Axis a) const { @@ -538,12 +460,17 @@ Grob::relative_coordinate (Grob const*refp, Axis a) const not ask for the absolute coordinate (ie. REFP == nil.) */ - if (refp == dim_cache_[a].parent_l_) + if (refp == dim_cache_[a].parent_) return get_offset (a); else - return get_offset (a) + dim_cache_[a].parent_l_->relative_coordinate (refp, a); + return get_offset (a) + dim_cache_[a].parent_->relative_coordinate (refp, a); } + + +/* + Invoke callbacks to get offset relative to parent. +*/ Real Grob::get_offset (Axis a) const { @@ -580,13 +507,6 @@ Grob::empty_b (Axis a)const gh_procedure_p (dim_cache_[a].dimension_)); } -/* - TODO: add - - Grob *refpoint - - to arguments? - */ Interval Grob::extent (Grob * refp, Axis a) const { @@ -613,8 +533,8 @@ Grob::extent (Grob * refp, Axis a) const ext = ly_scm2interval (d->dimension_); SCM extra = get_grob_property (a == X_AXIS - ? "extra-extent-X" - : "extra-extent-Y"); + ? "extra-X-extent" + : "extra-Y-extent"); /* signs ? @@ -626,8 +546,8 @@ Grob::extent (Grob * refp, Axis a) const } extra = get_grob_property (a == X_AXIS - ? "minimum-extent-X" - : "minimum-extent-Y"); + ? "minimum-X-extent" + : "minimum-Y-extent"); if (gh_pair_p (extra)) { ext.unite (Interval (gh_scm2double (ly_car (extra)), @@ -639,6 +559,9 @@ Grob::extent (Grob * refp, Axis a) const return ext; } +/* + Find the group-element which has both #this# and #s# +*/ Grob * Grob::common_refpoint (Grob const* s, Axis a) const { @@ -646,8 +569,8 @@ Grob::common_refpoint (Grob const* s, Axis a) const I don't like the quadratic aspect of this code, but I see no other way. The largest chain of parents might be 10 high or so, so it shouldn't be a real issue. */ - for (Grob const *c = this; c; c = c->dim_cache_[a].parent_l_) - for (Grob const * d = s; d; d = d->dim_cache_[a].parent_l_) + for (Grob const *c = this; c; c = c->dim_cache_[a].parent_) + for (Grob const * d = s; d; d = d->dim_cache_[a].parent_) if (d == c) return (Grob*)d; @@ -656,14 +579,37 @@ Grob::common_refpoint (Grob const* s, Axis a) const Grob * -Grob::common_refpoint (SCM elist, Axis a) const +common_refpoint_of_list (SCM elist, Grob *common, Axis a) { - Grob * common = (Grob*) this; for (; gh_pair_p (elist); elist = ly_cdr (elist)) { Grob * s = unsmob_grob (ly_car (elist)); - if (s) + if (!s) + continue; + if (common) + common = common->common_refpoint (s, a); + else + common = s; + } + + return common; +} + + + +Grob * +common_refpoint_of_array (Link_array const &arr, Grob *common, Axis a) +{ + for (int i = arr.size() ; i--; ) + { + Grob * s = arr[i]; + if (!s) + continue; + + if (common) common = common->common_refpoint (s, a); + else + common = s; } return common; @@ -695,12 +641,6 @@ Grob::has_extent_callback_b (SCM cb, Axis a)const } -bool -Grob::has_extent_callback_b (Axis a) const -{ - return gh_procedure_p (dim_cache_[a].dimension_); -} - bool Grob::has_offset_callback_b (SCM cb, Axis a)const { @@ -708,7 +648,7 @@ Grob::has_offset_callback_b (SCM cb, Axis a)const } void -Grob::set_extent_callback (SCM dc, Axis a) +Grob::set_extent (SCM dc, Axis a) { dim_cache_[a].dimension_ =dc; } @@ -716,7 +656,7 @@ Grob::set_extent_callback (SCM dc, Axis a) void Grob::set_parent (Grob *g, Axis a) { - dim_cache_[a].parent_l_ = g; + dim_cache_[a].parent_ = g; } MAKE_SCHEME_CALLBACK (Grob,fixup_refpoint,1); @@ -732,9 +672,9 @@ Grob::fixup_refpoint (SCM smob) if (!parent) continue; - if (parent->line_l () != me->line_l () && me->line_l ()) + if (parent->get_system () != me->get_system () && me->get_system ()) { - Grob * newparent = parent->find_broken_piece (me->line_l ()); + Grob * newparent = parent->find_broken_piece (me->get_system ()); me->set_parent (newparent, ax); } @@ -756,6 +696,29 @@ Grob::fixup_refpoint (SCM smob) return smob; } +void +Grob::warning (String s)const +{ + SCM cause = self_scm(); + while (Grob * g = unsmob_grob (cause)) + { + cause = g->get_grob_property ("cause"); + } + + if (Music *m = unsmob_music (cause)) + { + m->origin()->warning (s); + } + else + ::warning (s); +} + +void +Grob::programming_error (String s)const +{ + s = "Programming error: " + s; + warning (s); +} /**************************************************** @@ -772,21 +735,27 @@ Grob::mark_smob (SCM ses) { Grob * s = (Grob*) SCM_CELL_WORD_1 (ses); scm_gc_mark (s->immutable_property_alist_); - scm_gc_mark (s->mutable_property_alist_); for (int a =0 ; a < 2; a++) { scm_gc_mark (s->dim_cache_[a].offset_callbacks_); scm_gc_mark (s->dim_cache_[a].dimension_); - Grob *p = s->get_parent (Y_AXIS); - if (p) - scm_gc_mark (p->self_scm ()); + + /* + don't mark the parents. The pointers in the mutable property + list form two tree like structures (one for X relations, one + for Y relations). Marking these can be done in limited stack + space. If we add the parents, we will jump between X and Y in + an erratic manner, leading to much more recursion depth (and + core dumps if we link to pthreads.) + */ } - if (s->original_l_) - scm_gc_mark (s->original_l_->self_scm ()); + if (s->original_) + scm_gc_mark (s->original_->self_scm ()); - return s->do_derived_mark (); + s->do_derived_mark (); + return s->mutable_property_alist_; } int @@ -795,7 +764,7 @@ Grob::print_smob (SCM s, SCM port, scm_print_state *) Grob *sc = (Grob *) ly_cdr (s); scm_puts ("#name ().ch_C (), port); + scm_puts ((char *)sc->name ().to_str0 (), port); /* don't try to print properties, that is too much hassle. @@ -805,106 +774,89 @@ Grob::print_smob (SCM s, SCM port, scm_print_state *) } SCM -Grob::do_derived_mark () +Grob::do_derived_mark () const { return SCM_EOL; } -SCM -ly_set_grob_property (SCM elt, SCM sym, SCM val) -{ - Grob * sc = unsmob_grob (elt); - if (!gh_symbol_p (sym)) - { - error ("Not a symbol"); - ly_display_scm (sym); - return SCM_UNSPECIFIED; - } +void +Grob::discretionary_processing () +{ +} - if (!type_check_assignment (sym, val, ly_symbol2scm ("backend-type?"))) - return SCM_UNSPECIFIED; - - if (sc) - { - sc->internal_set_grob_property (sym, val); - } - else - { - error ("Not a score element"); - ly_display_scm (elt); - } +bool +Grob::internal_has_interface (SCM k) +{ + SCM ifs = get_grob_property ("interfaces"); - return SCM_UNSPECIFIED; + return scm_memq (k, ifs) != SCM_BOOL_F; } -SCM -ly_get_grob_property (SCM elt, SCM sym) +/** Return Array of Grobs in SCM list L */ +Link_array +ly_scm2grobs (SCM l) { - Grob * sc = unsmob_grob (elt); - - if (sc) - { - return sc->internal_get_grob_property (sym); - } - else + Link_array arr; + + for (SCM s = l; gh_pair_p (s); s = gh_cdr (s)) { - error ("Not a score element"); - ly_display_scm (elt); + SCM e = gh_car (s); + arr.push (unsmob_grob (e)); } - return SCM_UNSPECIFIED; -} - -void -Grob::discretionary_processing () -{ + arr.reverse (); + return arr; } - - +/** Return SCM list of Grob array A */ SCM -spanner_get_bound (SCM slur, SCM dir) +ly_grobs2scm (Link_array a) { - return dynamic_cast (unsmob_grob (slur))->get_bound (to_dir (dir))->self_scm (); -} + SCM s = SCM_EOL; + for (int i = a.size (); i; i--) + s = gh_cons (a[i-1]->self_scm (), s); + return s; +} +IMPLEMENT_TYPE_P (Grob, "ly:grob?"); -static void -init_functions () -{ - scm_c_define_gsubr ("ly-get-grob-property", 2, 0, 0, - (Scheme_function_unknown)ly_get_grob_property); - scm_c_define_gsubr ("ly-set-grob-property", 3, 0, 0, - (Scheme_function_unknown)ly_set_grob_property); - scm_c_define_gsubr ("ly-get-spanner-bound", 2 , 0, 0, - (Scheme_function_unknown) spanner_get_bound); -} +ADD_INTERFACE (Grob, "grob-interface", + "In music notation, lots of symbols are related in some way. You can +think of music notation as a graph where nodes are formed by the +symbols, and the arcs by their relations. A grob is a node in that +graph. The directed edges in the graph are formed by references to +other grobs (i.e. pointers). This big graph of grobs specifies the +notation problem. The solution of this problem is a description of the +printout in closed form, i.e. a list of values. These values are +Molecules. -bool -Grob::has_interface (SCM k) -{ - SCM ifs = get_grob_property ("interfaces"); +All grobs have an X and Y-position on the page. These X and Y positions +are stored in a relative format, so they can easily be combined by +stacking them, hanging one grob to the side of another, and coupling +them into a grouping-grob. - return scm_memq (k, ifs) != SCM_BOOL_F; -} +Each grob has a reference point (a.k.a. parent): the position of a grob +is stored relative to that reference point. For example the X-reference +point of a staccato dot usually is the note head that it applies +to. When the note head is moved, the staccato dot moves along +automatically. -void -Grob::set_interface (SCM k) -{ - if (has_interface (k)) - return ; - else - { - set_grob_property ("interfaces", - gh_cons (k, get_grob_property ("interfaces"))); - } -} +A grob is often associated with a symbol, but some grobs do not print +any symbols. They take care of grouping objects. For example, there is a +separate grob that stacks staves vertically. The @ref{NoteCollision} +is also an abstract grob: it only moves around chords, but doesn't print +anything. +", + "X-offset-callbacks Y-offset-callbacks X-extent-callback molecule cause +Y-extent-callback molecule-callback extra-offset spacing-procedure +staff-symbol interfaces dependencies X-extent Y-extent extra-X-extent +causes meta layer before-line-breaking-callback +after-line-breaking-callback extra-Y-extent minimum-X-extent +minimum-Y-extent transparent"); -ADD_SCM_INIT_FUNC (scoreelt, init_functions); -IMPLEMENT_TYPE_P (Grob, "ly-grob?");