ENG-21: Connect cross-voice arpeggios

Due to the one-to-one relationship between Arpeggios and Chords, there
is no ideal way to import arpeggios that include notes across voices;
currently, such a case results in the creation of one arpeggio for each
chord with notes containing the <arpeggiated> tag. This commit adds a
function to Score that iterates through these and connects them; this
function is called after the score has been imported.

Additionally, this commits corrects the exporting for this case, adding
the <arpeggiated> tag to not only notes in a chord with an arpeggio, but
notes that intersect an arpeggio in any voice in the given segment and
staff. This effectively creates a correct round-trip for cross-voice
arpeggios, although with the (theoretical) false positive of connecting
multiple arpeggios in the same segment in the same staff even if they
are intended to remain separate.

Duplicate of musescore#8506, plus fixing a merge conflict due to musescore#8199

Author: iveshenry18

importexport/musicxml/exportxml.cpp

@@ -2824,6 +2824,26 @@ void ExportMusicXml::chordAttributes(Chord* chord, Notations& notations, Technic
             }
       }
 
+//---------------------------------------------------------
+//   findArpeggio
+//---------------------------------------------------------
+
+static Arpeggio* findArpeggio(Note* note)
+      {
+      if (note->chord()->arpeggio()) return note->chord()->arpeggio();
+
+      // Check if there is an arpeggio in any voice that intersects the note on the y-axis
+      for (int i = staff2track(note->staffIdx()); i < staff2track(note->staffIdx() + 1); ++i) {
+            Element* elem =  note->chord()->segment()->elist()[i];
+            if (elem && elem->isChord()
+                  && toChord(elem)->arpeggio()
+                  && note->pageBoundingRect().top() + note->headHeight() >= toChord(elem)->arpeggio()->pageBoundingRect().top()
+                  && note->pageBoundingRect().top() + note->headHeight() <= toChord(elem)->arpeggio()->pageBoundingRect().bottom())
+                  return toChord(elem)->arpeggio();
+            }
+      return 0;
+      }
+
 //---------------------------------------------------------
 //   arpeggiate
 //---------------------------------------------------------
@@ -3464,8 +3484,8 @@ void ExportMusicXml::chord(Chord* chord, int staff, const std::vector<Lyrics*>*
                         }
 
             technical.etag(_xml);
-            if (chord->arpeggio()) {
-                  arpeggiate(chord->arpeggio(), note == nl.front(), note == nl.back(), _xml, notations);
+            if (Arpeggio* arp = findArpeggio(note)) {
+                  arpeggiate(arp, note == nl.front(), note == nl.back(), _xml, notations);
                   }
             for (Spanner* spanner : note->spannerFor())
                   if (spanner->type() == ElementType::GLISSANDO) {

importexport/musicxml/importmxmlpass2.cpp

@@ -1627,6 +1627,8 @@ void MusicXMLParserPass2::scorePartwise()
       auto lm = _score->lastMeasure();
       if (lm && lm->endBarLineType() == BarLineType::NORMAL)
             lm->setEndBarLineType(BarLineType::NORMAL, 0);
+
+      _score->connectArpeggios();
       }
 
 //---------------------------------------------------------

libmscore/layout.cpp

@@ -11,6 +11,7 @@
 //=============================================================================
 
 #include "accidental.h"
+#include "arpeggio.h"
 #include "barline.h"
 #include "beam.h"
 #include "box.h"
@@ -1525,6 +1526,56 @@ void Score::connectTies(bool silent)
             }
       }
 
+//---------------------------------------------------------
+//   connectArpeggios
+//  Fake cross-voice arpeggios by hiding all but the first
+//  and extending the first to cover the others.
+//  Retains the other properties of the first arpeggio.
+//---------------------------------------------------------
+
+void Score::connectArpeggios()
+      {
+      for (auto segment = firstSegment(SegmentType::ChordRest); segment; segment = segment->next1(SegmentType::ChordRest)) {
+            for (int staff = 0; staff < nstaves(); ++staff) {
+                  qreal minTop = 10000;
+                  qreal maxBottom = -10000;
+                  int firstArpeggio = -1;
+                  bool multipleArpeggios = false;
+                  for (int i = staff2track(staff); i < staff2track(staff + 1); ++i) {
+                        if (segment->elist()[i] && segment->elist()[i]->isChord()) {
+                              Chord* chord = toChord(segment->elist()[i]);
+                              if (chord->arpeggio() && chord->arpeggio()->visible()) {
+                                    if (chord->pagePos() == QPointF(0, 0)) doLayout();
+                                    qreal localTop = chord->arpeggio()->pageBoundingRect().top();                   
+                                    qreal localBottom = chord->arpeggio()->pageBoundingRect().bottom();                             
+                                    minTop = qMin(localTop, minTop);
+                                    maxBottom = qMax(localBottom, maxBottom);
+                                    if (firstArpeggio == -1)
+                                          // Leave arpeggio, adjust height after collecting
+                                          firstArpeggio = i;
+                                    else {
+                                          // Hide arpeggio; firstArpeggio will be extended to cover it.
+                                          chord->arpeggio()->setVisible(false);                                          
+                                          multipleArpeggios = true;
+                                          }
+                                    }
+                              }
+                        }
+                  if (firstArpeggio != -1 && multipleArpeggios) {
+                        // Stretch first arpeggio to cover deleted
+                        Chord* firstArpeggioChord = toChord(segment->elist()[firstArpeggio]);
+                        Arpeggio* arpeggio = firstArpeggioChord->arpeggio();
+                        qreal topDiff = minTop - arpeggio->pageBoundingRect().top();
+                        qreal bottomDiff = maxBottom - arpeggio->pageBoundingRect().bottom();
+                        arpeggio->setUserLen1(topDiff);
+                        arpeggio->setUserLen2(bottomDiff);
+                        arpeggio->setPropertyFlags(Pid::ARP_USER_LEN1, PropertyFlags::UNSTYLED);
+                        arpeggio->setPropertyFlags(Pid::ARP_USER_LEN2, PropertyFlags::UNSTYLED);
+                        }
+                  }
+            }
+      }
+
 //---------------------------------------------------------
 //   checkDivider
 //---------------------------------------------------------

libmscore/score.h

@@ -1035,6 +1035,7 @@ class Score : public QObject, public ScoreElement {
       Segment* lastSegmentMM() const;
 
       void connectTies(bool silent=false);
+      void connectArpeggios();
 
       qreal point(const Spatium sp) const { return sp.val() * spatium(); }