lily/vertical-align-engraver.cc

   1 /*
   2   vertical-align-engraver.cc -- implement Vertical_align_engraver
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1997--2005 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7 */
   8
   9 #include "context.hh"
  10 #include "paper-column.hh"
  11 #include "align-interface.hh"
  12 #include "span-bar.hh"
  13 #include "axis-group-interface.hh"
  14 #include "engraver.hh"
  15 #include "spanner.hh"
  16
  17 class Vertical_align_engraver : public Engraver
  18 {
  19   Spanner *valign_;
  20   bool qualifies (Grob_info) const;
  21   SCM id_to_group_hashtab_;
  22
  23 public:
  24   TRANSLATOR_DECLARATIONS (Vertical_align_engraver);
  25
  26 protected:
  27   virtual void derived_mark () const;
  28   virtual void acknowledge_grob (Grob_info);
  29   virtual void process_music ();
  30   virtual void finalize ();
  31   virtual void initialize ();
  32 };
  33
  34
  35 ADD_TRANSLATOR (Vertical_align_engraver,
  36                 "Catch groups (staffs, lyrics lines, etc.) and stack "
  37                 "them vertically.",
  38                 /* creats*/ "VerticalAlignment",
  39                 /* accepts */ "",
  40                 /* acks  */ "axis-group-interface",
  41                 /* reads */ "",
  42                 /* write */ "");
  43
  44
  45 Vertical_align_engraver::Vertical_align_engraver ()
  46 {
  47   valign_ = 0;
  48   id_to_group_hashtab_ = SCM_EOL;
  49 }
  50
  51 void
  52 Vertical_align_engraver::derived_mark () const
  53 {
  54   scm_gc_mark (id_to_group_hashtab_);
  55 }
  56
  57 void
  58 Vertical_align_engraver::initialize ()
  59 {
  60   id_to_group_hashtab_ = scm_c_make_hash_table (11);
  61 }
  62
  63
  64 void
  65 Vertical_align_engraver::process_music ()
  66 {
  67   if (!valign_)
  68     {
  69       valign_ = make_spanner ("VerticalAlignment", SCM_EOL);
  70       valign_->set_bound (LEFT, unsmob_grob (get_property ("currentCommandColumn")));
  71     }
  72 }
  73
  74 void
  75 Vertical_align_engraver::finalize ()
  76 {
  77   if (valign_)
  78     {
  79       valign_->set_bound (RIGHT, unsmob_grob (get_property ("currentCommandColumn")));
  80       valign_ = 0;
  81     }
  82 }
  83
  84 bool
  85 Vertical_align_engraver::qualifies (Grob_info i) const
  86 {
  87   int sz = i.origin_contexts ((Translator *)this).size ();
  88
  89   return sz > 0 && Axis_group_interface::has_interface (i.grob ())
  90     && !i.grob ()->get_parent (Y_AXIS) && Axis_group_interface::has_axis (i.grob (), Y_AXIS);
  91 }
  92
  93 void
  94 Vertical_align_engraver::acknowledge_grob (Grob_info i)
  95 {
  96   if (qualifies (i))
  97     {
  98       String id = i.context ()->id_string ();
  99
 100       scm_hash_set_x (id_to_group_hashtab_, scm_makfrom0str (id.to_str0 ()),
 101                       i.grob ()->self_scm ());
 102
 103
 104       SCM before_id = i.context ()->get_property ("alignAboveContext");
 105       SCM after_id = i.context ()->get_property ("alignBelowContext");
 106
 107       SCM before = scm_hash_ref (id_to_group_hashtab_,  before_id, SCM_BOOL_F);
 108       SCM after = scm_hash_ref (id_to_group_hashtab_,  after_id, SCM_BOOL_F);
 109
 110
 111       Align_interface::add_element (valign_, i.grob (),
 112                                     get_property ("verticalAlignmentChildCallback"));
 113
 114       if (unsmob_grob (before) || unsmob_grob (after))
 115         {
 116           SCM elts = valign_->get_property ("elements");
 117           SCM new_order = scm_cdr (elts);
 118           SCM *current = &new_order;
 119
 120           for (SCM s = new_order;  scm_is_pair (s); s = scm_cdr (s))
 121             {
 122               if (scm_car (s) == after)
 123                 {
 124                   *current = scm_cons (i.grob ()->self_scm(), s);
 125                   break;
 126                 }
 127               else if (scm_car (s) == before)
 128                 {
 129                   scm_set_cdr_x (s, scm_cons (i.grob ()->self_scm (),
 130                                               scm_cdr (s)));
 131                   break;
 132                 }
 133
 134               current = SCM_CDRLOC (s);
 135             }
 136
 137           valign_->set_property ("elements", new_order);
 138         }
 139     }
 140 }