new engraver for spacing in chordlyrics

verses_with_chords.ly

@@ -253,6 +253,113 @@
                                     (make-pad-right-markup -0.1 (make-tied-lyric-markup text))
                                     text))))
 
+Chord_lyrics_spacing_engraver =
+#(lambda (ctx)
+   (let ((last-note-head #f)
+         (note-head-extended #f)
+         (last-lyric-syllable-width 0)
+         (lyric-width-since-last-chord 0)
+         (notes-on-syllable-count 0)
+         (last-chord-name #f)
+         (remaining-chord-width 0)
+         (last-rest #f)
+         (rest-count 0)
+         (multi-measure-rest-count 0)
+         (stanza-shift 0))
+     (make-engraver
+      (listeners
+       ((multi-measure-rest-event engraver event)
+        (set! multi-measure-rest-count (+ multi-measure-rest-count 1))
+        )
+       ((break-event engraver event)
+        (set! last-note-head #f)
+        (set! note-head-extended #f)
+        (set! last-lyric-syllable-width 0)
+        (set! lyric-width-since-last-chord 0)
+        (set! notes-on-syllable-count 0)
+        (set! last-chord-name #f)
+        (set! remaining-chord-width 0)
+        (set! last-rest #f)
+        (set! rest-count 0)
+        (set! multi-measure-rest-count 0)
+        (set! stanza-shift 0)
+        ))
+      (acknowledgers
+       ((note-head-interface this-engraver grob source-engraver)
+        (if (and (> rest-count 0) (not last-note-head))
+            (let ((rest-spacing-on-line-start 1.2))
+              (ly:grob-set-property! grob 'minimum-X-extent (cons (- rest-spacing-on-line-start) 0))
+              (set! stanza-shift rest-spacing-on-line-start)
+              ))
+        (set! notes-on-syllable-count (+ 1 notes-on-syllable-count))
+        (set! last-note-head grob)
+        (set! note-head-extended #f)
+        (set! last-rest #f)
+        (set! rest-count 0)
+        (set! multi-measure-rest-count 0)
+        )
+       ((lyric-syllable-interface this-engraver grob source-engraver)
+        (set! remaining-chord-width (max 0 (- remaining-chord-width lyric-width-since-last-chord)))
+        (set! last-lyric-syllable-width (- (cdr (ly:grob-extent grob grob X)) 0.2))
+        (set! lyric-width-since-last-chord (+ lyric-width-since-last-chord last-lyric-syllable-width))
+        (if last-note-head (set! notes-on-syllable-count 1))
+        )
+       ((chord-name-interface this-engraver grob source-engraver)
+        (if (not (and
+                  (boolean? (ly:grob-property grob 'begin-of-line-visible))
+                  (ly:grob-property grob 'begin-of-line-visible)))
+            (let ((on-a-rest (> rest-count 0)))
+              (if (not on-a-rest)
+                  (set! notes-on-syllable-count (- notes-on-syllable-count 1)))
+              (if (and last-chord-name (= multi-measure-rest-count 1) (> lyric-width-since-last-chord remaining-chord-width))
+                  (ly:grob-set-property! last-chord-name 'extra-spacing-width (cons -0.1 (+ 0.1 (- lyric-width-since-last-chord remaining-chord-width)))))
+              (if last-note-head
+                  (let* ((last-note-min-x-extent (ly:grob-property last-note-head 'minimum-X-extent))
+                         (last-note-min-x-lower (if (pair? last-note-min-x-extent) (car last-note-min-x-extent) 0))
+                         (last-note-min-x-upper (if (pair? last-note-min-x-extent) (cdr last-note-min-x-extent) 0)))
+                    (if on-a-rest
+                        (begin
+                         (if (not note-head-extended)
+                             (begin
+                              (ly:grob-set-property! last-note-head 'minimum-X-extent
+                                                     (cons last-note-min-x-lower (- last-lyric-syllable-width -2 (* 2.2 rest-count))))
+                              (set! note-head-extended #t)
+                              ))
+                         (ly:grob-set-property! last-rest 'minimum-X-extent (cons 0 2))
+                         )
+                        (if (and (> lyric-width-since-last-chord 0)
+                                 (> remaining-chord-width lyric-width-since-last-chord))
+                            (ly:grob-set-property! last-note-head 'minimum-X-extent
+                                                   (cons (- -1.2 (- remaining-chord-width lyric-width-since-last-chord)) last-note-min-x-upper))
+                            (let* ((width-per-note-head 0.5)
+                                   (note-width-since-last-chord (* width-per-note-head notes-on-syllable-count)))
+                              (if (> remaining-chord-width note-width-since-last-chord)
+                                  (ly:grob-set-property! last-note-head 'minimum-X-extent
+                                                         (cons (- note-width-since-last-chord remaining-chord-width) last-note-min-x-upper))
+                                  )
+                              )
+                            )
+                        )))
+              (set! last-chord-name grob)
+              (set! remaining-chord-width
+                    (if (and on-a-rest (equal? (ly:prob-property (ly:grob-property grob 'cause) 'duration) (ly:prob-property (ly:grob-property last-rest 'cause) 'duration)))
+                        0
+                        (cdr (ly:grob-extent grob grob X))))
+              (set! lyric-width-since-last-chord 0)
+              (set! notes-on-syllable-count (if on-a-rest 0 1))
+              ))
+        )
+       ((rest-interface this-engraver grob source-engraver)
+        (set! rest-count (+ 1 rest-count))
+        (set! last-rest grob)
+        (set! multi-measure-rest-count 0)
+        )
+       ((stanza-number-interface this-engraver grob source-engraver)
+        (ly:grob-set-property! grob 'padding stanza-shift))
+       ))))
+
+%#(ly:set-option 'debug-skylines #t)
+
 #(define-markup-command (chordlyrics layout props lyrics) (ly:music?)
    #:properties ((verse-chords #{#})
                  (verse-reference-voice #{#})
@@ -298,6 +405,8 @@
              % \override SpacingSpanner.strict-note-spacing = ##t
               \override SpacingSpanner.uniform-stretching = ##t
               \override SpacingSpanner.spacing-increment = 0
+              %\override SpacingSpanner.packed-spacing = ##t
+              \consists \Chord_lyrics_spacing_engraver
               \remove Bar_number_engraver
               \remove Mark_engraver
               \remove Jump_engraver
@@ -330,9 +439,10 @@
               \NullVoice
               \consists Rest_engraver
               \omit Rest
+              \override Rest.X-extent = #'(0 . 0)
               \undo \omit NoteHead
               \hide NoteHead
-              \override NoteHead.X-extent = #'(0 . 0)
+              \override NoteHead.X-extent = #'(0 . 0.5)
             }
           }
         }