Issue 3254: align unassociated lyrics using NoteColumn extent. (issue 108110044 by address@hidden)

[janek . lilypond]

Reviewers: ,

Message:
Hi all!

Seems i'm back to LilyPond business (hopefully for long :)!
Please review - more patches (depending on this one) will follow.

best,
Janek

Description:
Issue 3254: align unassociated lyrics using NoteColumn extent.

This makes unassociated lyrics behave consistently with
associated lyrics.  Until now, "standalone" lyrics
were left-aligned (more precisely: their X-offset was 0);
changing self-alignment-X didn't have any effect on them.
Now it's possible to specify their alignment, like with
associated lyrics.

Later on, this should also allow correctly aligning_on_parent
other grobs (such as DynamicTexts).

Expected changes in output: all lyrics should be centered by default.

Please review this at https://codereview.appspot.com/108110044/

Affected files (+72, -3 lines):
  A input/regression/unassociated-lyrics-alignment.ly
  M lily/include/paper-column.hh
  M lily/paper-column.cc
  M lily/self-alignment-interface.cc


Index: input/regression/unassociated-lyrics-alignment.ly
diff --git a/input/regression/unassociated-lyrics-alignment.ly  
b/input/regression/unassociated-lyrics-alignment.ly
new file mode 100644
index  
0000000000000000000000000000000000000000..2b39447707aa7e00f363d40c58deb406b217f964
--- /dev/null
+++ b/input/regression/unassociated-lyrics-alignment.ly
@@ -0,0 +1,44 @@
+\version "2.19.9"
+#(set-global-staff-size 30)
+
+\header {
+  texidoc = "Lyrics without an associatedVoice should align properly.
+If there are notes in the PaperColumn, they should align to them,
+and when there are no notes, they should align relative to the
+PaperColumn itself (represented with blue GridLines here)"
+}
+
+\paper {
+  ragged-right = ##f
+}
+
+\layout {
+  \context {
+    \Voice
+    \consists "Grid_point_engraver"
+    gridInterval = #(ly:make-moment 1/4)
+    \override GridPoint.Y-extent = #'(-1 . 3)
+  }
+  \context {
+    \Staff
+    \consists "Grid_line_span_engraver"
+    \override GridLine.color = #blue
+  }
+}
+
+music = <<
+  \new Staff <<
+    \new Voice { s1*3 } % needed for gridLines
+    \new Voice { d'2 d' <f' g'>1 s1 }
+  >>
+  \new Lyrics { \lyricmode { foo2 bar mmmm1 a2 bom } }
+>>
+
+\markup "default (centered):"
+\music
+
+\markup "right-aligned:"
+{
+  \override Score.LyricText.self-alignment-X = #RIGHT
+  \music
+}
Index: lily/include/paper-column.hh
diff --git a/lily/include/paper-column.hh b/lily/include/paper-column.hh
index  
c1638a2539f45bf47121886f31c7b2a2f6cf294c..0d26c2b4a809166e9cfefd9662cb0ae62b0aab19  
100644
--- a/lily/include/paper-column.hh
+++ b/lily/include/paper-column.hh
@@ -59,6 +59,7 @@ public:
   static bool is_extraneous_column_from_ligature (Grob *);
   static Real minimum_distance (Grob *l, Grob *r);
   static Interval break_align_width (Grob *me, SCM align_sym);
+  static Interval get_generic_interface_extent (Grob *column, SCM  
interface, Axis a);
 };

 #endif // PAPER_COLUMN_HH
Index: lily/paper-column.cc
diff --git a/lily/paper-column.cc b/lily/paper-column.cc
index  
d5ac33b55a4e679c80d341258c296a45029c2b40..848c8e73855957743973b8f324acaad4262a54c9  
100644
--- a/lily/paper-column.cc
+++ b/lily/paper-column.cc
@@ -219,6 +219,23 @@ Paper_column::break_align_width (Grob *me, SCM  
align_sym)
 }

 /*
+  Loop through elements of a PaperColumn, find all grobs implementing  
specified
+  interface and return their combined extent.
+*/
+Interval
+Paper_column::get_generic_interface_extent (Grob *column, SCM interface,  
Axis a)
+{
+  Interval extent = Interval (0, 0);
+  extract_grob_set (column, "elements", elts);
+
+  for (vsize i = 0; i < elts.size (); i++)
+    if (elts[i]->internal_has_interface (interface))
+      extent.unite (robust_relative_extent (elts[i], elts[i], a));
+
+  return extent;
+}
+
+/*
   Print a:
   - vertical line,
   - the rank number,
Index: lily/self-alignment-interface.cc
diff --git a/lily/self-alignment-interface.cc  
b/lily/self-alignment-interface.cc
index  
e0b7f00cb2887fc6e1c1e9afd194aa0045f86e5d..744381d75dfbd1534e860f80f51db393780d4c33  
100644
--- a/lily/self-alignment-interface.cc
+++ b/lily/self-alignment-interface.cc
@@ -132,10 +132,17 @@ SCM
 Self_alignment_interface::aligned_on_parent (Grob *me, Axis a)
 {
   Grob *him = me->get_parent (a);
+  Interval he;
   if (Paper_column::has_interface (him))
-    return scm_from_double (0.0);
-
-  Interval he = him->extent (him, a);
+      /*
+        PaperColumn extents aren't reliable (they depend on size and  
alignment
+        of PaperColumn's children), so we align on NoteColumn instead.
+        This happens e.g. for lyrics without associatedVoice.
+      */
+    he = Paper_column::get_generic_interface_extent
+              (him, ly_symbol2scm ("note-column-interface"), a);
+  else
+    he = him->extent (him, a);

   SCM sym = (a == X_AXIS) ? ly_symbol2scm ("self-alignment-X")
             : ly_symbol2scm ("self-alignment-Y");