//=============================================================================
//  MuseScore
//  Music Composition & Notation
//
//  Copyright (C) 2002-2016 Werner Schweer
//
//  This program is free software; you can redistribute it and/or modify
//  it under the terms of the GNU General Public License version 2
//  as published by the Free Software Foundation and appearing in
//  the file LICENCE.GPL
//=============================================================================

/**
 \file
 Implementation of most part of class Measure.
*/

#include "log.h"

#include "measure.h"
#include "accidental.h"
#include "ambitus.h"
#include "articulation.h"
#include "barline.h"
#include "beam.h"
#include "box.h"
#include "bracket.h"
#include "breath.h"
#include "chord.h"
#include "clef.h"
#include "drumset.h"
#include "duration.h"
#include "dynamic.h"
#include "fermata.h"
#include "fret.h"
#include "glissando.h"
#include "hairpin.h"
#include "harmony.h"
#include "hook.h"
#include "icon.h"
#include "image.h"
#include "key.h"
#include "keysig.h"
#include "layoutbreak.h"
#include "layout.h"
#include "note.h"
#include "ottava.h"
#include "page.h"
#include "part.h"
#include "pedal.h"
#include "pitchspelling.h"
#include "repeat.h"
#include "rest.h"
#include "score.h"
#include "segment.h"
#include "select.h"
#include "sig.h"
#include "slur.h"
#include "spacer.h"
#include "staff.h"
#include "stafftext.h"
#include "stafftype.h"
#include "stringdata.h"
#include "style.h"
#include "sym.h"
#include "system.h"
#include "tempotext.h"
#include "measurenumber.h"
#include "tie.h"
#include "tiemap.h"
#include "timesig.h"
#include "tremolo.h"
#include "trill.h"
#include "tuplet.h"
#include "tupletmap.h"
#include "undo.h"
#include "utils.h"
#include "volta.h"
#include "xml.h"
#include "systemdivider.h"
#include "stafftypechange.h"
#include "stafflines.h"
#include "bracketItem.h"

namespace Ms {
//---------------------------------------------------------
//   MStaff
///   Per staff values of measure.
//---------------------------------------------------------

class MStaff
{
    MeasureNumber* _noText { 0 };           ///< Measure number text object
    StaffLines* _lines    { 0 };
    Spacer* _vspacerUp     { 0 };
    Spacer* _vspacerDown   { 0 };
    bool _hasVoices        { false };      ///< indicates that MStaff contains more than one voice,
                                           ///< this changes some layout rules
    bool _visible          { true };
    bool _stemless         { false };
#ifndef NDEBUG
    bool _corrupted        { false };
#endif

public:
    MStaff() {}
    ~MStaff();
    MStaff(const MStaff&);

    void setScore(Score*);
    void setTrack(int);

    MeasureNumber* noText() const { return _noText; }
    void setNoText(MeasureNumber* t) { _noText = t; }

    StaffLines* lines() const { return _lines; }
    void setLines(StaffLines* l) { _lines = l; }

    Spacer* vspacerUp() const { return _vspacerUp; }
    void setVspacerUp(Spacer* s) { _vspacerUp = s; }
    Spacer* vspacerDown() const { return _vspacerDown; }
    void setVspacerDown(Spacer* s) { _vspacerDown = s; }

    bool hasVoices() const { return _hasVoices; }
    void setHasVoices(bool val) { _hasVoices = val; }

    bool visible() const { return _visible; }
    void setVisible(bool val) { _visible = val; }

    bool stemless() const { return _stemless; }
    void setStemless(bool val) { _stemless = val; }

#ifndef NDEBUG
    bool corrupted() const { return _corrupted; }
    void setCorrupted(bool val) { _corrupted = val; }
#endif
};

MStaff::~MStaff()
{
    delete _noText;
    delete _lines;
    delete _vspacerUp;
    delete _vspacerDown;
}

MStaff::MStaff(const MStaff& m)
{
    _noText      = 0;
    _lines       = new StaffLines(*m._lines);
    _hasVoices   = m._hasVoices;
    _vspacerUp   = 0;
    _vspacerDown = 0;
    _visible     = m._visible;
    _stemless  = m._stemless;
#ifndef NDEBUG
    _corrupted   = m._corrupted;
#endif
}

//---------------------------------------------------------
//   MStaff::setScore
//---------------------------------------------------------

void MStaff::setScore(Score* score)
{
    if (_lines) {
        _lines->setScore(score);
    }
    if (_vspacerUp) {
        _vspacerUp->setScore(score);
    }
    if (_vspacerDown) {
        _vspacerDown->setScore(score);
    }
    if (_noText) {
        _noText->setScore(score);
    }
}

//---------------------------------------------------------
//   setTrack
//---------------------------------------------------------

void MStaff::setTrack(int track)
{
    if (_lines) {
        _lines->setTrack(track);
    }
    if (_vspacerUp) {
        _vspacerUp->setTrack(track);
    }
    if (_vspacerDown) {
        _vspacerDown->setTrack(track);
    }
    if (_noText) {
        _noText->setTrack(track);
    }
}

//---------------------------------------------------------
//   Measure
//---------------------------------------------------------

Measure::Measure(Score* s)
    : MeasureBase(s), _timesig(4,4)
{
    setTicks(Fraction(4,4));
    _repeatCount           = 2;

    int n = score()->nstaves();
    _mstaves.reserve(n);
    for (int staffIdx = 0; staffIdx < n; ++staffIdx) {
        MStaff* ms   = new MStaff;
        Staff* staff = score()->staff(staffIdx);
        ms->setLines(new StaffLines(score()));
        ms->lines()->setTrack(staffIdx * VOICES);
        ms->lines()->setParent(this);
        ms->lines()->setVisible(!staff->invisible());
        _mstaves.push_back(ms);
    }
    setIrregular(false);
    _noMode                   = MeasureNumberMode::AUTO;
    _userStretch              = 1.0;
    _breakMultiMeasureRest    = false;
    _mmRest                   = 0;
    _mmRestCount              = 0;
    setFlag(ElementFlag::MOVABLE, true);
}

//---------------------------------------------------------
//   measure
//---------------------------------------------------------

Measure::Measure(const Measure& m)
    : MeasureBase(m)
{
    _segments     = m._segments.clone();
    _timesig      = m._timesig;
    _len          = m._len;
    _repeatCount  = m._repeatCount;
    _noMode       = m._noMode;
    _userStretch  = m._userStretch;

    _mstaves.reserve(m._mstaves.size());
    for (MStaff* ms : m._mstaves) {
        _mstaves.push_back(new MStaff(*ms));
    }

    _breakMultiMeasureRest = m._breakMultiMeasureRest;
    _mmRest                = m._mmRest;
    _mmRestCount           = m._mmRestCount;
    _playbackCount         = m._playbackCount;
}

//---------------------------------------------------------
//   layoutStaffLines
//---------------------------------------------------------

void Measure::layoutStaffLines()
{
    for (MStaff* ms : _mstaves) {
        ms->lines()->layout();
    }
}

//---------------------------------------------------------
//   createStaves
//---------------------------------------------------------

void Measure::createStaves(int staffIdx)
{
    for (int n = int(_mstaves.size()); n <= staffIdx; ++n) {
        Staff* staff = score()->staff(n);
        MStaff* s    = new MStaff;
        s->setLines(new StaffLines(score()));
        s->lines()->setParent(this);
        s->lines()->setTrack(n * VOICES);
        s->lines()->setVisible(!staff->invisible());
        _mstaves.push_back(s);
    }
}

//---------------------------------------------------------
//   setScore
//---------------------------------------------------------

void Measure::setScore(Score* score)
{
    MeasureBase::setScore(score);
    for (Segment* s = first(); s; s = s->next()) {
        s->setScore(score);
    }
}

bool Measure::hasVoices(int staffIdx) const { return _mstaves[staffIdx]->hasVoices(); }
void Measure::setHasVoices(int staffIdx, bool v) { return _mstaves[staffIdx]->setHasVoices(v); }
StaffLines* Measure::staffLines(int staffIdx) { return _mstaves[staffIdx]->lines(); }
Spacer* Measure::vspacerDown(int staffIdx) const { return _mstaves[staffIdx]->vspacerDown(); }
Spacer* Measure::vspacerUp(int staffIdx) const { return _mstaves[staffIdx]->vspacerUp(); }
void Measure::setStaffVisible(int staffIdx, bool visible) { _mstaves[staffIdx]->setVisible(visible); }
void Measure::setStaffStemless(int staffIdx, bool stemless) { _mstaves[staffIdx]->setStemless(stemless); }

#ifndef NDEBUG
bool Measure::corrupted(int staffIdx) const { return _mstaves[staffIdx]->corrupted(); }
void Measure::setCorrupted(int staffIdx, bool val) { _mstaves[staffIdx]->setCorrupted(val); }
#endif

void Measure::setNoText(int staffIdx, MeasureNumber* t) { _mstaves[staffIdx]->setNoText(t); }
MeasureNumber* Measure::noText(int staffIdx) const { return _mstaves[staffIdx]->noText(); }

//---------------------------------------------------------
//   Measure
//---------------------------------------------------------

Measure::~Measure()
{
    for (Segment* s = first(); s;) {
        Segment* ns = s->next();
        delete s;
        s = ns;
    }
    qDeleteAll(_mstaves);
}

//---------------------------------------------------------
//   AcEl
//---------------------------------------------------------

struct AcEl {
    Note* note;
    qreal x;
};

//---------------------------------------------------------
//   findAccidental
///   return current accidental value at note position
//---------------------------------------------------------

AccidentalVal Measure::findAccidental(Note* note) const
{
    Chord* chord = note->chord();
    AccidentalState tversatz;    // state of already set accidentals for this measure
    tversatz.init(chord->staff()->keySigEvent(tick()), chord->staff()->clef(tick()));

    for (Segment* segment = first(); segment; segment = segment->next()) {
        int startTrack = chord->staffIdx() * VOICES;
        if (segment->isKeySigType()) {
            KeySig* ks = toKeySig(segment->element(startTrack));
            if (!ks) {
                continue;
            }
            tversatz.init(chord->staff()->keySigEvent(segment->tick()), chord->staff()->clef(segment->tick()));
        } else if (segment->segmentType() == SegmentType::ChordRest) {
            int endTrack   = startTrack + VOICES;
            for (int track = startTrack; track < endTrack; ++track) {
                Element* e = segment->element(track);
                if (!e || !e->isChord()) {
                    continue;
                }
                Chord* crd = toChord(e);
                for (Chord* chord1 : crd->graceNotes()) {
                    for (Note* note1 : chord1->notes()) {
                        if (note1->tieBack() && note1->accidental() == 0) {
                            continue;
                        }
                        //
                        // compute accidental
                        //
                        int tpc  = note1->tpc();
                        int line = absStep(tpc, note1->epitch());

                        if (note == note1) {
                            return tversatz.accidentalVal(line);
                        }
                        tversatz.setAccidentalVal(line, tpc2alter(tpc));
                    }
                }
                for (Note* note1 : crd->notes()) {
                    if (note1->tieBack() && note1->accidental() == 0) {
                        continue;
                    }
                    //
                    // compute accidental
                    //
                    int tpc  = note1->tpc();
                    int line = absStep(tpc, note1->epitch());

                    if (note == note1) {
                        return tversatz.accidentalVal(line);
                    }
                    tversatz.setAccidentalVal(line, tpc2alter(tpc));
                }
            }
        }
    }
    qDebug("Measure::findAccidental: note not found");
    return AccidentalVal::NATURAL;
}

//---------------------------------------------------------
//   findAccidental
///   Compute accidental state at segment/staffIdx for
///   relative staff line.
//---------------------------------------------------------

AccidentalVal Measure::findAccidental(Segment* s, int staffIdx, int line, bool& error) const
{
    AccidentalState tversatz;    // state of already set accidentals for this measure
    Staff* staff = score()->staff(staffIdx);
    tversatz.init(staff->keySigEvent(tick()), staff->clef(tick()));

    SegmentType st = SegmentType::ChordRest;
    int startTrack = staffIdx * VOICES;
    int endTrack   = startTrack + VOICES;
    for (Segment* segment = first(st); segment; segment = segment->next(st)) {
        if (segment == s && staff->isPitchedStaff(tick())) {
            ClefType clef = staff->clef(s->tick());
            int l = relStep(line, clef);
            return tversatz.accidentalVal(l, error);
        }
        for (int track = startTrack; track < endTrack; ++track) {
            Element* e = segment->element(track);
            if (!e || !e->isChord()) {
                continue;
            }
            Chord* chord = toChord(e);
            for (Chord* chord1 : chord->graceNotes()) {
                for (Note* note : chord1->notes()) {
                    if (note->tieBack() && note->accidental() == 0) {
                        continue;
                    }
                    int tpc  = note->tpc();
                    int l    = absStep(tpc, note->epitch());
                    tversatz.setAccidentalVal(l, tpc2alter(tpc));
                }
            }

            for (Note* note : chord->notes()) {
                if (note->tieBack() && note->accidental() == 0) {
                    continue;
                }
                int tpc    = note->tpc();
                int l      = absStep(tpc, note->epitch());
                tversatz.setAccidentalVal(l, tpc2alter(tpc));
            }
        }
    }
    qDebug("segment not found");
    return AccidentalVal::NATURAL;
}

//---------------------------------------------------------
//   tick2pos
//    return x position for tick relative to System
//---------------------------------------------------------

qreal Measure::tick2pos(Fraction tck) const
{
    tck -= ticks();
    if (isMMRest()) {
        Segment* s = first(SegmentType::ChordRest);
        qreal x1   = s->x();
        qreal w    = width() - x1;
        return x1 + (tck.ticks() * w) / (ticks().ticks() * mmRestCount());
    }

    Segment* s;
    qreal x1  = 0;
    qreal x2  = 0;
    Fraction tick1 = Fraction(0,1);
    Fraction tick2 = Fraction(0,1);
    for (s = first(SegmentType::ChordRest); s; s = s->next(SegmentType::ChordRest)) {
        x2    = s->x();
        tick2 = s->rtick();
        if (tck == tick2) {
            return x2 + pos().x();
        }
        if (tck <= tick2) {
            break;
        }
        x1    = x2;
        tick1 = tick2;
    }
    if (s == 0) {
        x2    = width();
        tick2 = ticks();
    }
    qreal dx = x2 - x1;
    Fraction dt   = tick2 - tick1;
    x1      += dt.isZero() ? 0.0 : (dx * (tck.ticks() - tick1.ticks()) / dt.ticks());
    return x1 + pos().x();
}

//---------------------------------------------------------
//   showsMeasureNumberInAutoMode
///    Wheter the measure will show measure number(s) when MeasureNumberMode is set to AUTO
//---------------------------------------------------------

bool Measure::showsMeasureNumberInAutoMode()
{
    // Check wheter any measure number should be shown
    if (!score()->styleB(Sid::showMeasureNumber)) {
        return false;
    }

    // Measure numbers should not be shown on irregular measures.
    if (irregular()) {
        return false;
    }

    // Measure numbers should not show on first measure unless specified with Sid::showMeasureNumberOne
    if (!no()) {
        return score()->styleB(Sid::showMeasureNumberOne);
    }

    if (score()->styleB(Sid::measureNumberSystem)) {
        // Show either if
        //   1) This is the first measure of the system OR
        //   2) The previous measure in the system is the first, and is irregular.
        return isFirstInSystem()
               || (prevMeasure() && prevMeasure()->irregular() && prevMeasure()->isFirstInSystem());
    } else {
        // In the case of an interval, we should show the measure number either if:
        //   1) We should show them every measure
        int interval = score()->styleI(Sid::measureNumberInterval);
        if (interval == 1) {
            return true;
        }

        //   2) (measureNumber + 1) % interval == 0 (or 1 if measure number one is numbered.)
        // If measure number 1 is numbered, and the interval is let's say 5, then we should number #1, 6, 11, 16, etc.
        // If measure number 1 is not numbered, with the same interval (5), then we should number #5, 10, 15, 20, etc.
        return ((no() + 1) % score()->styleI(Sid::measureNumberInterval))
               == (score()->styleB(Sid::showMeasureNumberOne) ? 1 : 0);
    }
}

//---------------------------------------------------------
//   showsMeasureNumber
///     Wheter the Measure shows a MeasureNumber
//---------------------------------------------------------

bool Measure::showsMeasureNumber()
{
    if (_noMode == MeasureNumberMode::SHOW) {
        return true;
    } else if (_noMode == MeasureNumberMode::HIDE) {
        return false;
    } else {
        return showsMeasureNumberInAutoMode();
    }
}

//---------------------------------------------------------
//   layoutMeasureNumber
///    Layouts the Measure Numbers according to the Measure's MeasureNumberMode
//---------------------------------------------------------

void Measure::layoutMeasureNumber()
{
    bool smn = showsMeasureNumber();

    QString s;
    if (smn) {
        s = QString("%1").arg(no() + 1);
    }
    unsigned nn = 1;
    bool nas = score()->styleB(Sid::measureNumberAllStaves);

    if (!nas) {
        //find first non invisible staff
        for (unsigned staffIdx = 0; staffIdx < _mstaves.size(); ++staffIdx) {
            MStaff* ms = _mstaves[staffIdx];
            SysStaff* ss  = system()->staff(staffIdx);
            Staff* staff = score()->staff(staffIdx);
            if (ms->visible() && staff->show() && ss->show()) {
                nn = staffIdx;
                break;
            }
        }
    }
    for (unsigned staffIdx = 0; staffIdx < _mstaves.size(); ++staffIdx) {
        MStaff* ms       = _mstaves[staffIdx];
        MeasureNumber* t = ms->noText();
        if (t) {
            t->setTrack(staffIdx * VOICES);
        }
        if (smn && ((staffIdx == nn) || nas)) {
            if (t == 0) {
                t = new MeasureNumber(score());
                t->setTrack(staffIdx * VOICES);
                t->setGenerated(true);
                t->setParent(this);
                add(t);
            }
            t->setXmlText(s);
            t->layout();
        } else {
            if (t) {
                if (t->generated()) {
                    score()->removeElement(t);
                } else {
                    score()->undo(new RemoveElement(t));
                }
            }
        }
    }
}

//---------------------------------------------------------
//   layout2
//    called after layout of page
//---------------------------------------------------------

void Measure::layout2()
{
    Q_ASSERT(parent());
    Q_ASSERT(score()->nstaves() == int(_mstaves.size()));

    qreal _spatium = spatium();

    for (int staffIdx = 0; staffIdx < score()->nstaves(); ++staffIdx) {
        MStaff* ms = _mstaves[staffIdx];
        Spacer* sp = ms->vspacerDown();
        if (sp) {
            sp->layout();
            Staff* staff = score()->staff(staffIdx);
            int n = staff->lines(tick()) - 1;
            qreal y = system()->staff(staffIdx)->y();
            sp->setPos(_spatium * .5, y + n * _spatium * staff->mag(tick()));
        }
        sp = ms->vspacerUp();
        if (sp) {
            sp->layout();
            qreal y = system()->staff(staffIdx)->y();
            sp->setPos(_spatium * .5, y - sp->gap());
        }
    }

    MeasureBase::layout();    // layout LAYOUT_BREAK elements

    //---------------------------------------------------
    //    layout ties
    //---------------------------------------------------

    Fraction stick = system()->measures().front()->tick();
    int tracks = score()->ntracks();
    static const SegmentType st { SegmentType::ChordRest };
    for (int track = 0; track < tracks; ++track) {
        if (!score()->staff(track / VOICES)->show()) {
            track += VOICES - 1;
            continue;
        }
        for (Segment* seg = first(st); seg; seg = seg->next(st)) {
            ChordRest* cr = seg->cr(track);
            if (!cr) {
                continue;
            }

            if (cr->isChord()) {
                Chord* c = toChord(cr);
                c->layoutSpanners(system(), stick);
            }
        }
    }
}

//---------------------------------------------------------
//   findChord
///   Search for chord at position \a tick in \a track
//---------------------------------------------------------

Chord* Measure::findChord(Fraction t, int track)
{
    t -= tick();
    for (Segment* seg = last(); seg; seg = seg->prev()) {
        if (seg->rtick() < t) {
            return 0;
        }
        if (seg->rtick() == t) {
            Element* el = seg->element(track);
            if (el && el->isChord()) {
                return toChord(el);
            }
        }
    }
    return 0;
}

//---------------------------------------------------------
//   findChordRest
///   Search for chord or rest at position \a tick at \a staff in \a voice.
//---------------------------------------------------------

ChordRest* Measure::findChordRest(Fraction t, int track)
{
    t -= tick();
    for (const Segment& seg : _segments) {
        if (seg.rtick() > t) {
            return 0;
        }
        if (seg.rtick() == t) {
            Element* el = seg.element(track);
            if (el && el->isChordRest()) {
                return toChordRest(el);
            }
        }
    }
    return 0;
}

//---------------------------------------------------------
//   tick2segment
//---------------------------------------------------------

Segment* Measure::tick2segment(const Fraction& _t, SegmentType st)
{
    Fraction t = _t - tick();
    for (Segment& s : _segments) {
        if (s.rtick() == t) {
            if (s.segmentType() & st) {
                return &s;
            }
        }
        if (s.rtick() > t) {
            break;
        }
    }
    return 0;
}

//---------------------------------------------------------
//   findSegmentR
//    Search for a segment of type st at measure relative
//    position t.
//---------------------------------------------------------

Segment* Measure::findSegmentR(SegmentType st, const Fraction& t) const
{
    Segment* s;
    if (t > (ticks() * Fraction(1,2))) {
        // search backwards
        for (s = last(); s && s->rtick() > t; s = s->prev()) {
        }
        while (s && s->prev() && s->prev()->rtick() == t) {
            s = s->prev();
        }
    } else {
        // search forwards
        for (s = first(); s && s->rtick() < t; s = s->next()) {
        }
    }
    for (; s && s->rtick() == t; s = s->next()) {
        if (s->segmentType() & st) {
            return s;
        }
    }
    return 0;
}

//---------------------------------------------------------
//   undoGetSegmentR
//---------------------------------------------------------

Segment* Measure::undoGetSegmentR(SegmentType type, const Fraction& t)
{
    Segment* s = findSegmentR(type, t);
    if (s == 0) {
        s = new Segment(this, type, t);
        score()->undoAddElement(s);
    }
    return s;
}

//---------------------------------------------------------
//   findFirstR
//    return first segment of type st at relative
//    position t.
//---------------------------------------------------------

Segment* Measure::findFirstR(SegmentType st, const Fraction& t) const
{
    Segment* s;
    // search forwards
    for (s = first(); s && s->rtick() <= t; s = s->next()) {
        if (s->segmentType() == st) {
            return s;
        }
    }
    return 0;
}

//---------------------------------------------------------
//   getSegmentR
///   Get a segment of type st at relative tick position t.
///   If the segment does not exist, it is created.
//---------------------------------------------------------

Segment* Measure::getSegmentR(SegmentType st, const Fraction& t)
{
    Segment* s = findSegmentR(st, t);
    if (!s) {
        s = new Segment(this, st, t);
        add(s);
    }
    return s;
}

//---------------------------------------------------------
//   add
///   Add new Element \a el to Measure.
//---------------------------------------------------------

void Measure::add(Element* e)
{
    e->setParent(this);
    ElementType type = e->type();

    switch (type) {
    case ElementType::SEGMENT:
    {
        Segment* seg   = toSegment(e);
        Fraction t     = seg->rtick();
        SegmentType st = seg->segmentType();
        Segment* s;

        for (s = first(); s && s->rtick() < t; s = s->next()) {
        }
        while (s && s->rtick() == t) {
            if (!seg->isChordRestType() && (seg->segmentType() == s->segmentType())) {
                qDebug("there is already a <%s> segment", seg->subTypeName());
                return;
            }
            if (s->segmentType() > st) {
                break;
            }
            s = s->next();
        }
        seg->setParent(this);
        _segments.insert(seg, s);
        //
        // update measure flags
        //
        if (seg->header()) {
            seg->measure()->setHeader(true);
        }
        if (seg->trailer()) {
            seg->measure()->setTrailer(true);
        }
    }
    break;

    case ElementType::MEASURE_NUMBER:
        if (e->staffIdx() < int(_mstaves.size())) {
            _mstaves[e->staffIdx()]->setNoText(toMeasureNumber(e));
        }
        break;

    case ElementType::SPACER:
    {
        Spacer* sp = toSpacer(e);
        switch (sp->spacerType()) {
        case SpacerType::UP:
            _mstaves[e->staffIdx()]->setVspacerUp(sp);
            break;
        case SpacerType::DOWN:
        case SpacerType::FIXED:
            _mstaves[e->staffIdx()]->setVspacerDown(sp);
            break;
        }
        sp->setGap(sp->gap());            // trigger relayout
    }
    break;
    case ElementType::JUMP:
        setRepeatJump(true);
    // fall through

    case ElementType::MARKER:
        el().push_back(e);
        break;

    case ElementType::HBOX:
        if (e->staff()) {
            e->setMag(e->staff()->mag(tick()));                 // ?!
        }
        el().push_back(e);
        break;

    case ElementType::MEASURE:
        _mmRest = toMeasure(e);
        break;

    case ElementType::STAFFTYPE_CHANGE:
    {
        StaffTypeChange* stc = toStaffTypeChange(e);
        Staff* staff = stc->staff();
        const StaffType* st = stc->staffType();
        StaffType* nst;
        // st needs to point to the stafftype element within the stafftypelist for the staff
        if (st) {
            // executed on read, undo/redo, clone
            // setStaffType adds a copy to list and returns a pointer to that element within list
            // we won't need the original after that
            // this requires that st was allocated via new to begin with!
            nst = staff->setStaffType(tick(), *st);
            delete st;
        } else {
            // executed on add from palette
            // staffType returns a pointer to the current stafftype element in the list
            // setStaffType will make a copy and return a pointer to that element within list
            st  = staff->staffType(tick());
            nst = staff->setStaffType(tick(), *st);
        }
        staff->staffTypeListChanged(tick());
        stc->setStaffType(nst);
        MeasureBase::add(e);
    }
    break;

    default:
        MeasureBase::add(e);
        break;
    }
}

//---------------------------------------------------------
//   remove
///   Remove Element \a el from Measure.
//---------------------------------------------------------

void Measure::remove(Element* e)
{
    Q_ASSERT(e->parent() == this);
    Q_ASSERT(e->score() == score());

    switch (e->type()) {
    case ElementType::SEGMENT:
    {
        Segment* s = toSegment(e);
        _segments.remove(s);
        //
        // update measure flags
        //
        if (s->header()) {
            s->measure()->checkHeader();
        }
        if (s->trailer()) {
            s->measure()->checkTrailer();
        }
    }
    break;

    case ElementType::MEASURE_NUMBER:
        _mstaves[e->staffIdx()]->setNoText(nullptr);
        break;

    case ElementType::SPACER:
        switch (toSpacer(e)->spacerType()) {
        case SpacerType::DOWN:
        case SpacerType::FIXED:
            _mstaves[e->staffIdx()]->setVspacerDown(0);
            break;
        case SpacerType::UP:
            _mstaves[e->staffIdx()]->setVspacerUp(0);
            break;
        }
        break;

    case ElementType::JUMP:
        setRepeatJump(false);
    // fall through

    case ElementType::MARKER:
    case ElementType::HBOX:
        if (!el().remove(e)) {
            qDebug("Measure(%p)::remove(%s,%p) not found", this, e->name(), e);
        }
        break;

    case ElementType::CLEF:
    case ElementType::CHORD:
    case ElementType::REST:
    case ElementType::TIMESIG:
        for (Segment* segment = first(); segment; segment = segment->next()) {
            int staves = score()->nstaves();
            int tracks = staves * VOICES;
            for (int track = 0; track < tracks; ++track) {
                Element* ee = segment->element(track);
                if (ee == e) {
                    segment->setElement(track, 0);
                    return;
                }
            }
        }
        qDebug("Measure::remove: %s %p not found", e->name(), e);
        break;

    case ElementType::MEASURE:
        _mmRest = 0;
        break;

    case ElementType::STAFFTYPE_CHANGE:
    {
        StaffTypeChange* stc = toStaffTypeChange(e);
        Staff* staff = stc->staff();
        if (staff) {
            // st currently points to an list element that is about to be removed
            // make a copy now to use on undo/redo
            StaffType* st = new StaffType(*stc->staffType());
            if (!tick().isZero()) {
                staff->removeStaffType(tick());
            }
            stc->setStaffType(st);
        }
        MeasureBase::remove(e);
    }
    break;

    default:
        MeasureBase::remove(e);
        break;
    }
}

//---------------------------------------------------------
//   change
//---------------------------------------------------------

void Measure::change(Element* o, Element* n)
{
    if (o->isTuplet()) {
        Tuplet* t = toTuplet(n);
        for (DurationElement* e : t->elements()) {
            e->setTuplet(t);
        }
    } else {
        remove(o);
        add(n);
    }
}

//---------------------------------------------------------
//   spatiumChanged
//---------------------------------------------------------

void Measure::spatiumChanged(qreal /*oldValue*/, qreal /*newValue*/)
{
}

//-------------------------------------------------------------------
//   moveTicks
//    Also adjust endBarLine if measure len has changed. For this
//    diff == 0 cannot be optimized away
//-------------------------------------------------------------------

void Measure::moveTicks(const Fraction& diff)
{
    std::set<Tuplet*> tuplets;
    setTick(tick() + diff);
    for (Segment* segment = last(); segment; segment = segment->prev()) {
        if (segment->segmentType() & (SegmentType::EndBarLine | SegmentType::TimeSigAnnounce)) {
            segment->setRtick(ticks());
        } else if (segment->isChordRestType()) {
            // Tuplet ticks are stored as absolute ticks, so they must be adjusted.
            // But each tuplet must only be adjusted once.
            for (Element* e : segment->elist()) {
                if (e) {
                    ChordRest* cr = toChordRest(e);
                    Tuplet* tuplet = cr->tuplet();
                    if (tuplet && tuplets.count(tuplet) == 0) {
                        tuplets.insert(tuplet);
                    }
                }
            }
        }
    }
    tuplets.clear();
}

//---------------------------------------------------------
//   removeStaves
//---------------------------------------------------------

void Measure::removeStaves(int sStaff, int eStaff)
{
    for (Segment* s = first(); s; s = s->next()) {
        for (int staff = eStaff - 1; staff >= sStaff; --staff) {
            s->removeStaff(staff);
        }
    }
    for (Element* e : el()) {
        if (e->track() == -1) {
            continue;
        }
        int voice = e->voice();
        int staffIdx = e->staffIdx();
        if (staffIdx >= eStaff) {
            staffIdx -= eStaff - sStaff;
            e->setTrack(staffIdx * VOICES + voice);
        }
    }
}

//---------------------------------------------------------
//   insertStaves
//---------------------------------------------------------

void Measure::insertStaves(int sStaff, int eStaff)
{
    for (Element* e : el()) {
        if (e->track() == -1) {
            continue;
        }
        int staffIdx = e->staffIdx();
        if (staffIdx >= sStaff && !e->systemFlag()) {
            int voice = e->voice();
            staffIdx += eStaff - sStaff;
            e->setTrack(staffIdx * VOICES + voice);
        }
    }
    for (Segment* s = first(); s; s = s->next()) {
        for (int staff = sStaff; staff < eStaff; ++staff) {
            s->insertStaff(staff);
        }
    }
}

//---------------------------------------------------------
//   cmdRemoveStaves
//---------------------------------------------------------

void Measure::cmdRemoveStaves(int sStaff, int eStaff)
{
    int sTrack = sStaff * VOICES;
    int eTrack = eStaff * VOICES;
    for (Segment* s = first(); s; s = s->next()) {
        for (int track = eTrack - 1; track >= sTrack; --track) {
            Element* el = s->element(track);
            if (el) {
                el->undoUnlink();
                score()->undo(new RemoveElement(el));
            }
        }
        foreach (Element* e, s->annotations()) {
            int staffIdx = e->staffIdx();
            if ((staffIdx >= sStaff) && (staffIdx < eStaff) && !e->systemFlag()) {
                e->undoUnlink();
                score()->undo(new RemoveElement(e));
            }
        }
    }
    for (Element* e : el()) {
        if (e->track() == -1) {
            continue;
        }
        int staffIdx = e->staffIdx();
        if (staffIdx >= sStaff && (staffIdx < eStaff) && !e->systemFlag()) {
            e->undoUnlink();
            score()->undo(new RemoveElement(e));
        }
    }

    score()->undo(new RemoveStaves(this, sStaff, eStaff));

    for (int i = eStaff - 1; i >= sStaff; --i) {
        MStaff* ms = *(_mstaves.begin() + i);
        score()->undo(new RemoveMStaff(this, ms, i));
    }

    // barLine
    // TODO
}

//---------------------------------------------------------
//   cmdAddStaves
//---------------------------------------------------------

void Measure::cmdAddStaves(int sStaff, int eStaff, bool createRest)
{
    score()->undo(new InsertStaves(this, sStaff, eStaff));

    Segment* ts = findSegment(SegmentType::TimeSig, tick());
    Segment* bs = findSegmentR(SegmentType::EndBarLine, ticks());

    for (int i = sStaff; i < eStaff; ++i) {
        Staff* staff = score()->staff(i);
        MStaff* ms   = new MStaff;
        ms->setLines(new StaffLines(score()));
        ms->lines()->setTrack(i * VOICES);
        ms->lines()->setParent(this);
        ms->lines()->setVisible(!staff->invisible());
        score()->undo(new InsertMStaff(this, ms, i));
    }

    if (!createRest && !ts) {
        return;
    }

    // create list of unique staves (only one instance for linked staves):

    QList<int> sl;
    for (int staffIdx = sStaff; staffIdx < eStaff; ++staffIdx) {
        Staff* s = score()->staff(staffIdx);
        if (s->links()) {
            bool alreadyInList = false;
            for (int idx : sl) {
                if (s->links()->contains(score()->staff(idx))) {
                    alreadyInList = true;
                    break;
                }
            }
            if (alreadyInList) {
                continue;
            }
        }
        sl.append(staffIdx);
    }

    for (int staffIdx : sl) {
        if (createRest) {
            score()->setRest(tick(), staffIdx * VOICES, ticks(), false, 0, _timesig == ticks());
        }

        // replicate time signature
        if (ts) {
            TimeSig* ots = 0;
            bool constructed = false;
            for (unsigned track = 0; track < _mstaves.size() * VOICES; ++track) {
                if (ts->element(track)) {
                    ots = toTimeSig(ts->element(track));
                    break;
                }
            }
            if (!ots) {
                // no time signature found; use measure timesig to construct one
                ots = new TimeSig(score());
                ots->setSig(timesig());
                constructed = true;
            }
            // do no replicate local time signatures
            if (ots && !ots->isLocal()) {
                TimeSig* timesig = new TimeSig(*ots);
                timesig->setTrack(staffIdx * VOICES);
                timesig->setParent(ts);
                timesig->setSig(ots->sig(), ots->timeSigType());
                score()->undoAddElement(timesig);
                if (constructed) {
                    delete ots;
                }
            }
        }

        // replicate barline
        if (bs) {
            BarLine* obl = nullptr;
            for (unsigned track = 0; track < _mstaves.size() * VOICES; ++track) {
                Element* e = bs->element(track);
                if (e && !e->generated()) {
                    obl = toBarLine(e);
                    break;
                }
            }
            if (obl) {
                BarLine* barline = new BarLine(*obl);
                barline->setSpanStaff(score()->staff(staffIdx)->barLineSpan());
                barline->setTrack(staffIdx * VOICES);
                barline->setParent(bs);
                barline->setGenerated(false);
                score()->undoAddElement(barline);
            }
        }
    }
}

//---------------------------------------------------------
//   insertMStaff
//---------------------------------------------------------

void Measure::insertMStaff(MStaff* staff, int idx)
{
    _mstaves.insert(_mstaves.begin() + idx, staff);
    for (unsigned staffIdx = 0; staffIdx < _mstaves.size(); ++staffIdx) {
        _mstaves[staffIdx]->setTrack(staffIdx * VOICES);
    }
}

//---------------------------------------------------------
//   removeMStaff
//---------------------------------------------------------

void Measure::removeMStaff(MStaff* /*staff*/, int idx)
{
    _mstaves.erase(_mstaves.begin() + idx);
    for (unsigned staffIdx = 0; staffIdx < _mstaves.size(); ++staffIdx) {
        _mstaves[staffIdx]->setTrack(staffIdx * VOICES);
    }
}

//---------------------------------------------------------
//   insertStaff
//---------------------------------------------------------

void Measure::insertStaff(Staff* staff, int staffIdx)
{
    for (Segment* s = first(); s; s = s->next()) {
        s->insertStaff(staffIdx);
    }

    MStaff* ms = new MStaff;
    ms->setLines(new StaffLines(score()));
    ms->lines()->setParent(this);
    ms->lines()->setTrack(staffIdx * VOICES);
    ms->lines()->setVisible(!staff->invisible());
    insertMStaff(ms, staffIdx);
}

//---------------------------------------------------------
//   staffabbox
//---------------------------------------------------------

QRectF Measure::staffabbox(int staffIdx) const
{
    System* s = system();
    QRectF sb(s->staff(staffIdx)->bbox());
    QRectF rrr(sb.translated(s->pagePos()));
    QRectF rr(abbox());
    QRectF r(rr.x(), rrr.y(), rr.width(), rrr.height());
    return r;
}

//---------------------------------------------------------
//   acceptDrop
//---------------------------------------------------------

/**
 Return true if an Element of type \a type can be dropped on a Measure
*/

bool Measure::acceptDrop(EditData& data) const
{
    MuseScoreView* viewer = data.view;
    QPointF pos           = data.pos;
    Element* e            = data.dropElement;

    int staffIdx;
    Segment* seg;
    if (!score()->pos2measure(pos, &staffIdx, 0, &seg, 0)) {
        return false;
    }

    QRectF staffR = system()->staff(staffIdx)->bbox().translated(system()->canvasPos());
    staffR &= canvasBoundingRect();

    switch (e->type()) {
    case ElementType::MEASURE_LIST:
    case ElementType::JUMP:
    case ElementType::MARKER:
    case ElementType::LAYOUT_BREAK:
    case ElementType::STAFF_LIST:
        viewer->setDropRectangle(canvasBoundingRect());
        return true;

    case ElementType::KEYSIG:
    case ElementType::TIMESIG:
        if (data.modifiers & Qt::ControlModifier) {
            viewer->setDropRectangle(staffR);
        } else {
            viewer->setDropRectangle(canvasBoundingRect());
        }
        return true;

    case ElementType::MEASURE_NUMBER:
        viewer->setDropRectangle(canvasBoundingRect());
        return true;

    case ElementType::BRACKET:
    case ElementType::REPEAT_MEASURE:
    case ElementType::MEASURE:
    case ElementType::SPACER:
    case ElementType::IMAGE:
    case ElementType::BAR_LINE:
    case ElementType::SYMBOL:
    case ElementType::CLEF:
    case ElementType::STAFFTYPE_CHANGE:
        viewer->setDropRectangle(staffR);
        return true;

    case ElementType::ICON:
        switch (toIcon(e)->iconType()) {
        case IconType::VFRAME:
        case IconType::HFRAME:
        case IconType::TFRAME:
        case IconType::FFRAME:
        case IconType::MEASURE:
            viewer->setDropRectangle(canvasBoundingRect());
            return true;
        default:
            break;
        }
        break;

    default:
        break;
    }
    return false;
}

//---------------------------------------------------------
//   drop
///   Drop element.
///   Handle a dropped element at position \a pos of given
///   element \a type and \a subtype.
//---------------------------------------------------------

Element* Measure::drop(EditData& data)
{
    Element* e = data.dropElement;
    int staffIdx = -1;
    Segment* seg;
    score()->pos2measure(data.pos, &staffIdx, 0, &seg, 0);

    if (e->systemFlag()) {
        staffIdx = 0;
    }
    if (staffIdx < 0) {
        return 0;
    }
    Staff* staff = score()->staff(staffIdx);
    //bool fromPalette = (e->track() == -1);

    switch (e->type()) {
    case ElementType::MEASURE_LIST:
        delete e;
        break;

    case ElementType::STAFF_LIST:
//TODO                  score()->pasteStaff(e, this, staffIdx);
        delete e;
        break;

    case ElementType::MARKER:
    case ElementType::JUMP:
        e->setParent(this);
        e->setTrack(0);
        score()->undoAddElement(e);
        return e;

    case ElementType::DYNAMIC:
    case ElementType::FRET_DIAGRAM:
        e->setParent(seg);
        e->setTrack(staffIdx * VOICES);
        score()->undoAddElement(e);
        return e;

    case ElementType::IMAGE:
    case ElementType::SYMBOL:
        e->setParent(seg);
        e->setTrack(staffIdx * VOICES);
        e->layout();
        {
            QPointF uo(data.pos - e->canvasPos() - data.dragOffset);
            e->setOffset(uo);
        }
        score()->undoAddElement(e);
        return e;

    case ElementType::MEASURE_NUMBER:
        undoChangeProperty(Pid::MEASURE_NUMBER_MODE, static_cast<int>(MeasureNumberMode::SHOW));
        delete e;
        break;

    case ElementType::BRACKET:
    {
        Bracket* b = toBracket(e);
        int level = 0;
        int firstStaff = 0;
        for (Staff* s : score()->staves()) {
            for (const BracketItem* bi : s->brackets()) {
                int lastStaff = firstStaff + bi->bracketSpan() - 1;
                if (staffIdx >= firstStaff && staffIdx <= lastStaff) {
                    ++level;
                }
            }
            firstStaff++;
        }
        Selection sel = score()->selection();
        score()->undoAddBracket(staff, level, b->bracketType(), sel.staffEnd() - sel.staffStart());
        delete b;
    }
    break;

    case ElementType::CLEF:
        score()->undoChangeClef(staff, this, toClef(e)->clefType());
        delete e;
        break;

    case ElementType::KEYSIG:
    {
        KeySigEvent k = toKeySig(e)->keySigEvent();
        delete e;

        if (data.modifiers & Qt::ControlModifier) {
            // apply only to this stave
            score()->undoChangeKeySig(staff, tick(), k);
        } else {
            // apply to all staves:
            for (Staff* s : score()->staves()) {
                score()->undoChangeKeySig(s, tick(), k);
            }
        }

        break;
    }

    case ElementType::TIMESIG:
        score()->cmdAddTimeSig(this, staffIdx, toTimeSig(e), data.modifiers & Qt::ControlModifier);
        break;

    case ElementType::LAYOUT_BREAK: {
        LayoutBreak* b = toLayoutBreak(e);
        Measure* measure = isMMRest() ? mmRestLast() : this;
        switch (b->layoutBreakType()) {
        case  LayoutBreak::PAGE:
            if (measure->pageBreak()) {
                delete b;
                b = 0;
            } else {
                measure->setLineBreak(false);
            }
            break;
        case  LayoutBreak::LINE:
            if (measure->lineBreak()) {
                delete b;
                b = 0;
            } else {
                measure->setPageBreak(false);
            }
            break;
        case  LayoutBreak::SECTION:
            if (measure->sectionBreak()) {
                delete b;
                b = 0;
            } else {
                measure->setLineBreak(false);
            }
            break;
        case LayoutBreak::NOBREAK:
            if (measure->noBreak()) {
                delete b;
                b = 0;
            } else {
                measure->setLineBreak(false);
                measure->setPageBreak(false);
            }
            break;
        }
        if (b) {
            b->setTrack(-1);                   // these are system elements
            b->setParent(measure);
            score()->undoAddElement(b);
        }
        measure->cleanupLayoutBreaks(true);
        return b;
    }

    case ElementType::SPACER:
    {
        Spacer* spacer = toSpacer(e);
        spacer->setTrack(staffIdx * VOICES);
        spacer->setParent(this);
        if (spacer->spacerType() == SpacerType::FIXED) {
            qreal gap = spatium() * 10;
            System* s = system();
            const int nextVisStaffIdx = s->nextVisibleStaff(staffIdx);
            const bool systemEnd = (nextVisStaffIdx == score()->nstaves());
            if (systemEnd) {
                System* ns = 0;
                for (System* ts : score()->systems()) {
                    if (ns) {
                        ns = ts;
                        break;
                    }
                    if (ts == s) {
                        ns = ts;
                    }
                }
                if (ns && ns->page() == s->page()) {
                    qreal y1 = s->staffYpage(staffIdx);
                    qreal y2 = ns->staffYpage(0);
                    gap = y2 - y1 - score()->staff(staffIdx)->height();
                }
            } else {
                qreal y1 = s->staffYpage(staffIdx);
                qreal y2 = s->staffYpage(nextVisStaffIdx);
                gap = y2 - y1 - score()->staff(staffIdx)->height();
            }
            spacer->setGap(gap);
        }
        score()->undoAddElement(spacer);
        triggerLayout();
        return spacer;
    }

    case ElementType::BAR_LINE:
    {
        BarLine* bl = toBarLine(e);

        // if dropped bar line refers to span rather than to subtype
        // or if Ctrl key used
        if ((bl->spanFrom() && bl->spanTo()) || data.control()) {
            // get existing bar line for this staff, and drop the change to it
            seg = undoGetSegmentR(SegmentType::EndBarLine, ticks());
            BarLine* cbl = toBarLine(seg->element(staffIdx * VOICES));
            if (cbl) {
                cbl->drop(data);
            }
        } else if (bl->barLineType() == BarLineType::START_REPEAT) {
            Measure* m2 = isMMRest() ? mmRestFirst() : this;
            for (Score* lscore : score()->scoreList()) {
                Measure* lmeasure = lscore->tick2measure(m2->tick());
                if (lmeasure) {
                    lmeasure->undoChangeProperty(Pid::REPEAT_START, true);
                }
            }
        } else if (bl->barLineType() == BarLineType::END_REPEAT) {
            Measure* m2 = isMMRest() ? mmRestLast() : this;
            for (Score* lscore : score()->scoreList()) {
                Measure* lmeasure = lscore->tick2measure(m2->tick());
                if (lmeasure) {
                    lmeasure->undoChangeProperty(Pid::REPEAT_END, true);
                }
            }
        } else if (bl->barLineType() == BarLineType::END_START_REPEAT) {
            Measure* m2 = isMMRest() ? mmRestLast() : this;
            for (Score* lscore : score()->scoreList()) {
                Measure* lmeasure = lscore->tick2measure(m2->tick());
                if (lmeasure) {
                    lmeasure->undoChangeProperty(Pid::REPEAT_END, true);
                    lmeasure = lmeasure->nextMeasure();
                    if (lmeasure) {
                        lmeasure->undoChangeProperty(Pid::REPEAT_START, true);
                    }
                }
            }
        } else {
            // drop to first end barline
            seg = findSegmentR(SegmentType::EndBarLine, ticks());
            if (seg) {
                for (Element* ee : seg->elist()) {
                    if (ee) {
                        ee->drop(data);
                        break;
                    }
                }
            } else {
                delete e;
            }
        }
        break;
    }

    case ElementType::REPEAT_MEASURE:
    {
        delete e;
        return cmdInsertRepeatMeasure(staffIdx);
    }
    case ElementType::ICON:
        switch (toIcon(e)->iconType()) {
        case IconType::VFRAME:
            score()->insertMeasure(ElementType::VBOX, this);
            break;
        case IconType::HFRAME:
            score()->insertMeasure(ElementType::HBOX, this);
            break;
        case IconType::TFRAME:
            score()->insertMeasure(ElementType::TBOX, this);
            break;
        case IconType::FFRAME:
            score()->insertMeasure(ElementType::FBOX, this);
            break;
        case IconType::MEASURE:
            score()->insertMeasure(ElementType::MEASURE, this);
            break;
        default:
            break;
        }
        break;

    case ElementType::STAFFTYPE_CHANGE:
    {
        e->setParent(this);
        e->setTrack(staffIdx * VOICES);
        score()->undoAddElement(e);
    }
    break;

    default:
        qDebug("Measure: cannot drop %s here", e->name());
        delete e;
        break;
    }
    return 0;
}

//---------------------------------------------------------
//   cmdInsertRepeatMeasure
//---------------------------------------------------------

RepeatMeasure* Measure::cmdInsertRepeatMeasure(int staffIdx)
{
    //
    // see also cmdDeleteSelection()
    //
    score()->select(0, SelectType::SINGLE, 0);
    for (Segment* s = first(); s; s = s->next()) {
        if (s->segmentType() & SegmentType::ChordRest) {
            int strack = staffIdx * VOICES;
            int etrack = strack + VOICES;
            for (int track = strack; track < etrack; ++track) {
                Element* el = s->element(track);
                if (el) {
                    score()->undoRemoveElement(el);
                }
            }
        }
    }
    //
    // add repeat measure
    //
    Segment* seg = undoGetSegment(SegmentType::ChordRest, tick());
    RepeatMeasure* rm = new RepeatMeasure(score());
    rm->setTrack(staffIdx * VOICES);
    rm->setParent(seg);
    rm->setDurationType(TDuration::DurationType::V_MEASURE);
    rm->setTicks(stretchedLen(score()->staff(staffIdx)));
    score()->undoAddCR(rm, this, tick());
    for (Element* e : el()) {
        if (e->isSlur() && e->staffIdx() == staffIdx) {
            score()->undoRemoveElement(e);
        }
    }
    return rm;
}

//---------------------------------------------------------
//   adjustToLen
//    change actual measure len, adjust elements to
//    new len
//---------------------------------------------------------

void Measure::adjustToLen(Fraction nf, bool appendRestsIfNecessary)
{
    Fraction ol   = ticks();
    Fraction nl   = nf;
    Fraction diff = nl - ol;

    Fraction startTick = endTick();
    if (diff < Fraction(0,1)) {
        startTick += diff;
    }

    score()->undoInsertTime(startTick, diff);
    score()->undo(new InsertTime(score(), startTick, diff));

    for (Score* s : score()->scoreList()) {
        Measure* m = s->tick2measure(tick());
        s->undo(new ChangeMeasureLen(m, nf));
        if (nl > ol) {
            // move EndBarLine, TimeSigAnnounce, KeySigAnnounce
            for (Segment* seg = m->first(); seg; seg = seg->next()) {
                if (seg->segmentType()
                    & (SegmentType::EndBarLine | SegmentType::TimeSigAnnounce | SegmentType::KeySigAnnounce)) {
                    seg->setRtick(nl);
                }
            }
        }
    }
    Score* s      = score()->masterScore();
    Measure* m    = s->tick2measure(tick());
    QList<int> sl = s->uniqueStaves();

    for (int staffIdx : sl) {
        int rests  = 0;
        int chords = 0;
        Rest* rest = 0;
        for (Segment* segment = m->first(); segment; segment = segment->next()) {
            int strack = staffIdx * VOICES;
            int etrack = strack + VOICES;
            for (int track = strack; track < etrack; ++track) {
                Element* e = segment->element(track);
                if (e) {
                    if (e->isRest()) {
                        ++rests;
                        rest = toRest(e);
                    } else if (e->isChord()) {
                        ++chords;
                    }
                }
            }
        }
        Fraction stretch = s->staff(staffIdx)->timeStretch(tick());
        // if just a single rest
        if (rests == 1 && chords == 0) {
            // if measure value didn't change, stick to whole measure rest
            if (_timesig == nf) {
                rest->undoChangeProperty(Pid::DURATION, QVariant::fromValue<Fraction>(nf * stretch));
                rest->undoChangeProperty(Pid::DURATION_TYPE,
                                         QVariant::fromValue<TDuration>(TDuration::DurationType::V_MEASURE));
            } else {          // if measure value did change, represent with rests actual measure value
#if 0
                // any reason not to do this instead?
                s->undoRemoveElement(rest);
                s->setRest(tick(), staffIdx * VOICES, nf * stretch, false, 0, false);
#else
                // convert the measure duration in a list of values (no dots for rests)
                std::vector<TDuration> durList = toDurationList(nf * stretch, false, 0);

                // set the existing rest to the first value of the duration list
                for (ScoreElement* e : rest->linkList()) {
                    e->undoChangeProperty(Pid::DURATION, QVariant::fromValue<Fraction>(durList[0].fraction()));
                    e->undoChangeProperty(Pid::DURATION_TYPE, QVariant::fromValue<TDuration>(durList[0]));
                }

                // add rests for any other duration list value
                Fraction tickOffset = tick() + rest->actualTicks();
                for (unsigned i = 1; i < durList.size(); i++) {
                    Rest* newRest = new Rest(s);
                    newRest->setDurationType(durList.at(i));
                    newRest->setTicks(durList.at(i).fraction());
                    newRest->setTrack(rest->track());
                    score()->undoAddCR(newRest, this, tickOffset);
                    tickOffset += newRest->actualTicks();
                }
#endif
            }
            continue;
        }

        int strack = staffIdx * VOICES;
        int etrack = strack + VOICES;

        for (int trk = strack; trk < etrack; ++trk) {
            Fraction n = diff;
            bool rFlag = false;
            if (n < Fraction(0,1)) {
                for (Segment* segment = m->last(); segment;) {
                    Segment* pseg = segment->prev();
                    if (segment->segmentType() == SegmentType::ChordRest) {
                        for (Element* a : segment->annotations()) {
                            if (a->track() == trk) {
                                s->undoRemoveElement(a);
                            }
                        }
                        Element* e = segment->element(trk);
                        if (e && e->isChordRest()) {
                            ChordRest* cr = toChordRest(e);
                            if (cr->durationType() == TDuration::DurationType::V_MEASURE) {
                                Fraction actualTicks = cr->actualTicks();
                                n += actualTicks;
                                cr->setDurationType(TDuration(actualTicks));
                            } else {
                                n += cr->actualTicks();
                            }
                            s->undoRemoveElement(e);
                            if (n >= Fraction(0,1)) {
                                break;
                            }
                        }
                    } else if (segment->segmentType() == SegmentType::Breath) {
                        Element* e = segment->element(trk);
                        if (e) {
                            s->undoRemoveElement(e);
                        }
                    }
                    segment = pseg;
                }
                rFlag = true;
            }
            int voice = trk % VOICES;
            if (appendRestsIfNecessary && (n > Fraction(0,1)) && (rFlag || voice == 0)) {
                // add rest to measure
                Fraction rtick = tick() + nl - n;
                int track = staffIdx * VOICES + voice;
                s->setRest(rtick, track, n * stretch, false, 0, false);
            }
        }
    }
    if (diff < Fraction(0,1)) {
        //
        //  CHECK: do not remove all slurs
        //
        for (Element* e : m->el()) {
            if (e->isSlur()) {
                s->undoRemoveElement(e);
            }
        }
    }
}

//---------------------------------------------------------
//   write
//---------------------------------------------------------

void Measure::write(XmlWriter& xml, int staff, bool writeSystemElements, bool forceTimeSig) const
{
    if (MScore::debugMode) {
        const int mno = no() + 1;
        xml.comment(QString("Measure %1").arg(mno));
    }
    if (_len != _timesig) {
        // this is an irregular measure
        xml.stag(this, QString("len=\"%1/%2\"").arg(_len.numerator()).arg(_len.denominator()));
    } else {
        xml.stag(this);
    }

    xml.setCurTick(tick());
    xml.setCurTrack(staff * VOICES);

    if (_mmRestCount > 0) {
        xml.tag("multiMeasureRest", _mmRestCount);
    }
    if (writeSystemElements) {
        if (repeatStart()) {
            xml.tagE("startRepeat");
        }
        if (repeatEnd()) {
            xml.tag("endRepeat", _repeatCount);
        }
        writeProperty(xml, Pid::IRREGULAR);
        writeProperty(xml, Pid::BREAK_MMR);
        writeProperty(xml, Pid::USER_STRETCH);
        writeProperty(xml, Pid::NO_OFFSET);
        writeProperty(xml, Pid::MEASURE_NUMBER_MODE);
    }
    qreal _spatium = spatium();
    MStaff* mstaff = _mstaves[staff];
    if (mstaff->noText() && !mstaff->noText()->generated()) {
        mstaff->noText()->write(xml);
    }

    if (mstaff->vspacerUp()) {
        xml.tag("vspacerUp", mstaff->vspacerUp()->gap() / _spatium);
    }
    if (mstaff->vspacerDown()) {
        if (mstaff->vspacerDown()->spacerType() == SpacerType::FIXED) {
            xml.tag("vspacerFixed", mstaff->vspacerDown()->gap() / _spatium);
        } else {
            xml.tag("vspacerDown", mstaff->vspacerDown()->gap() / _spatium);
        }
    }
    if (!mstaff->visible()) {
        xml.tag("visible", mstaff->visible());
    }
    if (mstaff->stemless()) {
        xml.tag("slashStyle", mstaff->stemless());     // for backwards compatibility
        xml.tag("stemless", mstaff->stemless());
    }

    int strack = staff * VOICES;
    int etrack = strack + VOICES;
    for (const Element* e : el()) {
        if (!e->generated() && ((e->staffIdx() == staff) || (e->systemFlag() && writeSystemElements))) {
            e->write(xml);
        }
    }
    Q_ASSERT(first());
    Q_ASSERT(last());
    if (first() && last()) {
        score()->writeSegments(xml, strack, etrack, first(), last()->next1(), writeSystemElements, forceTimeSig);
    }

    xml.etag();
}

//---------------------------------------------------------
//   Measure::read
//---------------------------------------------------------

void Measure::read(XmlReader& e, int staffIdx)
{
    qreal _spatium = spatium();
    e.setCurrentMeasure(this);
    int nextTrack = staffIdx * VOICES;
    e.setTrack(nextTrack);

    for (int n = int(_mstaves.size()); n <= staffIdx; ++n) {
        Staff* staff = score()->staff(n);
        MStaff* s    = new MStaff;
        s->setLines(new StaffLines(score()));
        s->lines()->setParent(this);
        s->lines()->setTrack(n * VOICES);
        s->lines()->setVisible(!staff->invisible());
        _mstaves.push_back(s);
    }

    bool irregular;
    if (e.hasAttribute("len")) {
        QStringList sl = e.attribute("len").split('/');
        if (sl.size() == 2) {
            _len = Fraction(sl[0].toInt(), sl[1].toInt());
        } else {
            qDebug("illegal measure size <%s>", qPrintable(e.attribute("len")));
        }
        irregular = true;
        if (_len.numerator() <= 0 || _len.denominator() <= 0) {
            e.raiseError(QObject::tr("MSCX error at line %1: invalid measure length: %2").arg(e.lineNumber()).arg(_len.
                                                                                                                  toString()));
            return;
        }
        score()->sigmap()->add(tick().ticks(), SigEvent(_len, _timesig));
        score()->sigmap()->add((tick() + ticks()).ticks(), SigEvent(_timesig));
    } else {
        irregular = false;
    }

    while (e.readNextStartElement()) {
        const QStringRef& tag(e.name());

        if (tag == "voice") {
            e.setTrack(nextTrack++);
            e.setTick(tick());
            readVoice(e, staffIdx, irregular);
        } else if (tag == "Image") {
            if (MScore::noImages) {
                e.skipCurrentElement();
            } else {
                Element* el = Element::name2Element(tag, score());
                el->setTrack(staffIdx * VOICES);
                el->read(e);
                add(el);
            }
        } else if (tag == "Marker" || tag == "Jump") {
            Element* el = Element::name2Element(tag, score());
            el->setTrack(e.track());
            el->read(e);
            add(el);
        } else if (tag == "stretch") {
            double val = e.readDouble();
            if (val < 0.0) {
                val = 0;
            }
            setUserStretch(val);
        } else if (tag == "noOffset") {
            setNoOffset(e.readInt());
        } else if (tag == "measureNumberMode") {
            setMeasureNumberMode(MeasureNumberMode(e.readInt()));
        } else if (tag == "irregular") {
            setIrregular(e.readBool());
        } else if (tag == "breakMultiMeasureRest") {
            _breakMultiMeasureRest = e.readBool();
        } else if (tag == "startRepeat") {
            setRepeatStart(true);
            e.readNext();
        } else if (tag == "endRepeat") {
            _repeatCount = e.readInt();
            setRepeatEnd(true);
        } else if (tag == "vspacer" || tag == "vspacerDown") {
            if (!_mstaves[staffIdx]->vspacerDown()) {
                Spacer* spacer = new Spacer(score());
                spacer->setSpacerType(SpacerType::DOWN);
                spacer->setTrack(staffIdx * VOICES);
                add(spacer);
            }
            _mstaves[staffIdx]->vspacerDown()->setGap(e.readDouble() * _spatium);
        } else if (tag == "vspacerFixed") {
            if (!_mstaves[staffIdx]->vspacerDown()) {
                Spacer* spacer = new Spacer(score());
                spacer->setSpacerType(SpacerType::FIXED);
                spacer->setTrack(staffIdx * VOICES);
                add(spacer);
            }
            _mstaves[staffIdx]->vspacerDown()->setGap(e.readDouble() * _spatium);
        } else if (tag == "vspacerUp") {
            if (!_mstaves[staffIdx]->vspacerUp()) {
                Spacer* spacer = new Spacer(score());
                spacer->setSpacerType(SpacerType::UP);
                spacer->setTrack(staffIdx * VOICES);
                add(spacer);
            }
            _mstaves[staffIdx]->vspacerUp()->setGap(e.readDouble() * _spatium);
        } else if (tag == "visible") {
            _mstaves[staffIdx]->setVisible(e.readInt());
        } else if ((tag == "slashStyle") || (tag == "stemless")) {
            _mstaves[staffIdx]->setStemless(e.readInt());
        } else if (tag == "SystemDivider") {
            SystemDivider* sd = new SystemDivider(score());
            sd->read(e);
            add(sd);
        } else if (tag == "multiMeasureRest") {
            _mmRestCount = e.readInt();
            // set tick to previous measure
            setTick(e.lastMeasure()->tick());
            e.setTick(e.lastMeasure()->tick());
        } else if (tag == "MeasureNumber") {
            MeasureNumber* noText = new MeasureNumber(score());
            noText->read(e);
            noText->setTrack(e.track());
            add(noText);
        } else if (MeasureBase::readProperties(e)) {
        } else {
            e.unknown();
        }
    }
    e.checkConnectors();
    if (isMMRest()) {
        Measure* lm = e.lastMeasure();
        e.setTick(lm->tick() + lm->ticks());
    }
    e.setCurrentMeasure(nullptr);

    connectTremolo();
}

//---------------------------------------------------------
//   Measure::readVoice
//---------------------------------------------------------

void Measure::readVoice(XmlReader& e, int staffIdx, bool irregular)
{
    Segment* segment = nullptr;
    QList<Chord*> graceNotes;
    Beam* startingBeam = nullptr;
    Tuplet* tuplet = nullptr;
    Fermata* fermata = nullptr;

    Staff* staff = score()->staff(staffIdx);
    Fraction timeStretch(staff->timeStretch(tick()));

    while (e.readNextStartElement()) {
        const QStringRef& tag(e.name());

        if (tag == "location") {
            Location loc = Location::relative();
            loc.read(e);
            e.setLocation(loc);
        } else if (tag == "tick") {             // obsolete?
            qDebug("read midi tick");
            e.setTick(Fraction::fromTicks(score()->fileDivision(e.readInt())));
        } else if (tag == "BarLine") {
            BarLine* barLine = new BarLine(score());
            barLine->setTrack(e.track());
            barLine->read(e);
            //
            //  StartRepeatBarLine: at rtick == 0, always BarLineType::START_REPEAT
            //  BarLine:            in the middle of a measure, has no semantic
            //  EndBarLine:         at the end of a measure
            //  BeginBarLine:       first segment of a measure, systemic barline

            SegmentType st = SegmentType::Invalid;
            Fraction t = e.tick() - tick();
            if (t.isNotZero() && (t != ticks())) {
                st = SegmentType::BarLine;
            } else if (barLine->barLineType() == BarLineType::START_REPEAT && t.isZero()) {
                st = SegmentType::StartRepeatBarLine;
            } else if (barLine->barLineType() == BarLineType::START_REPEAT && t == ticks()) {
                // old version, ignore
                delete barLine;
                barLine = 0;
            } else if (t.isZero() && segment == 0) {
                st = SegmentType::BeginBarLine;
            } else {
                st = SegmentType::EndBarLine;
            }
            if (barLine) {
                segment = getSegmentR(st, t);
                segment->add(barLine);
                barLine->layout();
            }
            if (fermata) {
                segment->add(fermata);
                fermata = nullptr;
            }
        } else if (tag == "Chord") {
            Chord* chord = new Chord(score());
            chord->setTrack(e.track());
            chord->read(e);
            if (startingBeam) {
                startingBeam->add(chord);         // also calls chord->setBeam(startingBeam)
                startingBeam = nullptr;
            }
//                  if (tuplet && !chord->isGrace())
//                        chord->readAddTuplet(tuplet);
            segment = getSegment(SegmentType::ChordRest, e.tick());
            if (chord->noteType() != NoteType::NORMAL) {
                graceNotes.push_back(chord);
            } else {
                segment->add(chord);
                for (int i = 0; i < graceNotes.size(); ++i) {
                    Chord* gc = graceNotes[i];
                    gc->setGraceIndex(i);
                    chord->add(gc);
                }
                graceNotes.clear();
                if (tuplet) {
                    tuplet->add(chord);
                }
                e.incTick(chord->actualTicks());
            }
            if (fermata) {
                segment->add(fermata);
                fermata = nullptr;
            }
        } else if (tag == "Rest") {
            Rest* rest = new Rest(score());
            rest->setDurationType(TDuration::DurationType::V_MEASURE);
            rest->setTicks(timesig() / timeStretch);
            rest->setTrack(e.track());
            rest->read(e);
            if (startingBeam) {
                startingBeam->add(rest);         // also calls rest->setBeam(startingBeam)
                startingBeam = nullptr;
            }
            segment = getSegment(SegmentType::ChordRest, e.tick());
            segment->add(rest);
            if (fermata) {
                segment->add(fermata);
                fermata = nullptr;
            }

            if (!rest->ticks().isValid()) {         // hack
                rest->setTicks(timesig() / timeStretch);
            }

            if (tuplet) {
                tuplet->add(rest);
            }
            e.incTick(rest->actualTicks());
        } else if (tag == "Breath") {
            Breath* breath = new Breath(score());
            breath->setTrack(e.track());
            breath->read(e);
            segment = getSegment(SegmentType::Breath, e.tick());
            segment->add(breath);
        } else if (tag == "Spanner") {
            Spanner::readSpanner(e, this, e.track());
        } else if (tag == "RepeatMeasure") {
            RepeatMeasure* rm = new RepeatMeasure(score());
            rm->setTrack(e.track());
            rm->read(e);
            segment = getSegment(SegmentType::ChordRest, e.tick());
            segment->add(rm);
            e.incTick(ticks());
        } else if (tag == "Clef") {
            Clef* clef = new Clef(score());
            clef->setTrack(e.track());
            clef->read(e);
            clef->setGenerated(false);

            // there may be more than one clef segment for same tick position
            // the first clef may be missing and is added later in layout

            bool header;
            if (e.tick() != tick()) {
                header = false;
            } else if (!segment) {
                header = true;
            } else {
                header = true;
                for (Segment* s = _segments.first(); s && s->rtick().isZero(); s = s->next()) {
                    if (s->isKeySigType() || s->isTimeSigType()) {
                        // hack: there may be other segment types which should
                        // generate a clef at current position
                        header = false;
                        break;
                    }
                }
            }
            segment = getSegment(header ? SegmentType::HeaderClef : SegmentType::Clef, e.tick());
            segment->add(clef);
        } else if (tag == "TimeSig") {
            TimeSig* ts = new TimeSig(score());
            ts->setTrack(e.track());
            ts->read(e);
            // if time sig not at beginning of measure => courtesy time sig
            Fraction currTick = e.tick();
            bool courtesySig = (currTick > tick());
            if (courtesySig) {
                // if courtesy sig., just add it without map processing
                segment = getSegment(SegmentType::TimeSigAnnounce, currTick);
                segment->add(ts);
            } else {
                // if 'real' time sig., do full process
                segment = getSegment(SegmentType::TimeSig, currTick);
                segment->add(ts);

                timeStretch = ts->stretch().reduced();
                _timesig    = ts->sig() / timeStretch;

                if (irregular) {
                    score()->sigmap()->add(tick().ticks(), SigEvent(_len, _timesig));
                    score()->sigmap()->add((tick() + ticks()).ticks(), SigEvent(_timesig));
                } else {
                    _len = _timesig;
                    score()->sigmap()->add(tick().ticks(), SigEvent(_timesig));
                }
            }
        } else if (tag == "KeySig") {
            KeySig* ks = new KeySig(score());
            ks->setTrack(e.track());
            ks->read(e);
            Fraction curTick = e.tick();
            if (!ks->isCustom() && !ks->isAtonal() && ks->key() == Key::C && curTick.isZero()) {
                // ignore empty key signature
                qDebug("remove keysig c at tick 0");
            } else {
                // if key sig not at beginning of measure => courtesy key sig
                bool courtesySig = (curTick == endTick());
                segment = getSegment(courtesySig ? SegmentType::KeySigAnnounce : SegmentType::KeySig, curTick);
                segment->add(ks);
                if (!courtesySig) {
                    staff->setKey(curTick, ks->keySigEvent());
                }
            }
        } else if (tag == "Text") {
            StaffText* t = new StaffText(score());
            t->setTrack(e.track());
            t->read(e);
            if (t->empty()) {
                qDebug("==reading empty text: deleted");
                delete t;
            } else {
                segment = getSegment(SegmentType::ChordRest, e.tick());
                segment->add(t);
            }
        }
        //----------------------------------------------------
        // Annotation
        else if (tag == "Dynamic") {
            Dynamic* dyn = new Dynamic(score());
            dyn->setTrack(e.track());
            dyn->read(e);
            segment = getSegment(SegmentType::ChordRest, e.tick());
            segment->add(dyn);
        } else if (tag == "Harmony"
                   || tag == "FretDiagram"
                   || tag == "TremoloBar"
                   || tag == "Symbol"
                   || tag == "Tempo"
                   || tag == "StaffText"
                   || tag == "Sticking"
                   || tag == "SystemText"
                   || tag == "RehearsalMark"
                   || tag == "InstrumentChange"
                   || tag == "StaffState"
                   || tag == "FiguredBass"
                   ) {
            Element* el = Element::name2Element(tag, score());
            // hack - needed because tick tags are unreliable in 1.3 scores
            // for symbols attached to anything but a measure
            el->setTrack(e.track());
            el->read(e);
            segment = getSegment(SegmentType::ChordRest, e.tick());
            segment->add(el);
        } else if (tag == "Fermata") {
            fermata = new Fermata(score());
            fermata->setTrack(e.track());
            fermata->setPlacement(fermata->track() & 1 ? Placement::BELOW : Placement::ABOVE);
            fermata->read(e);
        }
        // There could be an Image here if the score was saved with an earlier version of MuseScore 3.
        // This image would not have been visible upon reload. Let's read it in and add it directly
        // to the measure so that it can be displayed.
        else if (tag == "Image") {
            if (MScore::noImages) {
                e.skipCurrentElement();
            } else {
                Element* el = Element::name2Element(tag, score());
                el->setTrack(e.track());
                el->read(e);
                add(el);
            }
        }
        //----------------------------------------------------
        else if (tag == "Tuplet") {
            Tuplet* oldTuplet = tuplet;
            tuplet = new Tuplet(score());
            tuplet->setTrack(e.track());
            tuplet->setTick(e.tick());
            tuplet->setParent(this);
            tuplet->read(e);
            if (oldTuplet) {
                oldTuplet->add(tuplet);
            }
        } else if (tag == "endTuplet") {
            if (!tuplet) {
                qDebug("Measure::read: encountered <endTuplet/> when no tuplet was started");
                e.skipCurrentElement();
                continue;
            }
            Tuplet* oldTuplet = tuplet;
            tuplet = tuplet->tuplet();
            if (oldTuplet->elements().empty()) {
                // this should not happen and is a sign of input file corruption
                qDebug("Measure:read: empty tuplet in measure index=%d, input file corrupted?",
                       e.currentMeasureIndex());
                if (tuplet) {
                    tuplet->remove(oldTuplet);
                }
                delete oldTuplet;
            }
            e.readNext();
        } else if (tag == "Beam") {
            Beam* beam = new Beam(score());
            beam->setTrack(e.track());
            beam->read(e);
            beam->setParent(0);
            if (startingBeam) {
                qDebug("The read beam was not used");
                delete startingBeam;
            }
            startingBeam = beam;
        } else if (tag == "Segment" && segment) {
            segment->read(e);
        } else if (tag == "Ambitus") {
            Ambitus* range = new Ambitus(score());
            range->read(e);
            segment = getSegment(SegmentType::Ambitus, e.tick());
            range->setParent(segment);                // a parent segment is needed for setTrack() to work
            range->setTrack(trackZeroVoice(e.track()));
            segment->add(range);
        } else {
            e.unknown();
        }
    }
    if (startingBeam) {
        qDebug("The read beam was not used");
        delete startingBeam;
    }
    if (tuplet) {
        qDebug("Measure:readVoice: measure index=%d, <endTuplet/> not found", e.currentMeasureIndex());
        if (tuplet->elements().empty()) {
            if (tuplet->tuplet()) {
                tuplet->tuplet()->remove(tuplet);
            }
            delete tuplet;
        }
    }
    if (fermata) {
        SegmentType st = (e.tick() == endTick() ? SegmentType::EndBarLine : SegmentType::ChordRest);
        segment = getSegment(st, e.tick());
        segment->add(fermata);
        fermata = nullptr;
    }
}

//---------------------------------------------------------
//   Measure::readAddConnector
//---------------------------------------------------------

void Measure::readAddConnector(ConnectorInfoReader* info, bool pasteMode)
{
    const ElementType type = info->type();
    switch (type) {
    case ElementType::HAIRPIN:
    case ElementType::PEDAL:
    case ElementType::OTTAVA:
    case ElementType::TRILL:
    case ElementType::TEXTLINE:
    case ElementType::LET_RING:
    case ElementType::VIBRATO:
    case ElementType::PALM_MUTE:
    case ElementType::VOLTA:
    {
        Spanner* sp = toSpanner(info->connector());
        const Location& l = info->location();
        Fraction lTick    = l.frac();
        Fraction spTick   = pasteMode ? lTick : (tick() + lTick);
        if (info->isStart()) {
            sp->setTrack(l.track());
            sp->setTick(spTick);
            score()->addSpanner(sp);
        } else if (info->isEnd()) {
            sp->setTrack2(l.track());
            sp->setTick2(spTick);
        }
    }
    break;
    default:
        break;
    }
}

//---------------------------------------------------------
//   visible
//---------------------------------------------------------

bool Measure::visible(int staffIdx) const
{
    if (staffIdx >= score()->staves().size()) {
        qDebug("Measure::visible: bad staffIdx: %d", staffIdx);
        return false;
    }
    if (system() && (system()->staves()->empty() || !system()->staff(staffIdx)->show())) {
        return false;
    }
    if (score()->staff(staffIdx)->cutaway() && isEmpty(staffIdx)) {
        return false;
    }
    return score()->staff(staffIdx)->show() && _mstaves[staffIdx]->visible();
}

//---------------------------------------------------------
//   stemless
//---------------------------------------------------------

bool Measure::stemless(int staffIdx) const
{
    const Staff* staff = score()->staff(staffIdx);
    return staff->stemless(tick()) || _mstaves[staffIdx]->stemless() || staff->staffType(tick())->stemless();
}

//---------------------------------------------------------
//   isFinalMeasureOfSection
//    returns true if this measure is final actual measure of a section
//    takes into consideration fact that subsequent measures base objects
//    may have section break before encountering next actual measure
//---------------------------------------------------------

bool Measure::isFinalMeasureOfSection() const
{
    const MeasureBase* mb = static_cast<const MeasureBase*>(this);

    do {
        if (mb->sectionBreak()) {
            return true;
        }

        mb = mb->next();
    } while (mb && !mb->isMeasure());           // loop until reach next actual measure or end of score

    return false;
}

//---------------------------------------------------------
//   isAnacrusis
//---------------------------------------------------------

bool Measure::isAnacrusis() const
{
    TimeSigFrac timeSig = score()->sigmap()->timesig(tick().ticks()).nominal();
    return irregular() && ticks() < Fraction::fromTicks(timeSig.ticksPerMeasure());
}

//---------------------------------------------------------
//   isFirstInSystem
//---------------------------------------------------------

bool Measure::isFirstInSystem() const
{
    IF_ASSERT_FAILED(system()) {
        return false;
    }
    return system()->firstMeasure() == this;
}

//---------------------------------------------------------
//   scanElements
//---------------------------------------------------------

void Measure::scanElements(void* data, void (* func)(void*, Element*), bool all)
{
    MeasureBase::scanElements(data, func, all);

    int nstaves = score()->nstaves();
    for (int staffIdx = 0; staffIdx < nstaves; ++staffIdx) {
        if (!all && !(visible(staffIdx) && score()->staff(staffIdx)->show())) {
            continue;
        }
        MStaff* ms = _mstaves[staffIdx];
        func(data, ms->lines());
        if (ms->vspacerUp()) {
            func(data, ms->vspacerUp());
        }
        if (ms->vspacerDown()) {
            func(data, ms->vspacerDown());
        }
        if (ms->noText()) {
            func(data, ms->noText());
        }
    }

    for (Segment* s = first(); s; s = s->next()) {
        if (!s->enabled()) {
            continue;
        }
        s->scanElements(data, func, all);
    }
}

//---------------------------------------------------------
//   connectTremolo
///   Connect two-notes tremolo and update duration types
///   for the involved chords.
//---------------------------------------------------------

void Measure::connectTremolo()
{
    const int ntracks = score()->ntracks();
    constexpr SegmentType st = SegmentType::ChordRest;
    for (Segment* s = first(st); s; s = s->next(st)) {
        for (int i = 0; i < ntracks; ++i) {
            Element* e = s->element(i);
            if (!e || !e->isChord()) {
                continue;
            }

            Chord* c = toChord(e);
            Tremolo* tremolo = c->tremolo();
            if (tremolo && tremolo->twoNotes()) {
                // Ensure correct duration type for chord
                c->setDurationType(tremolo->durationType());

                // If it is the first tremolo's chord, find the second
                // chord for tremolo, if needed.
                if (!tremolo->chord1()) {
                    tremolo->setChords(c, tremolo->chord2());
                } else if (tremolo->chord1() != c || tremolo->chord2()) {
                    continue;
                }

                for (Segment* ls = s->next(st); ls; ls = ls->next(st)) {
                    if (Element* element = ls->element(i)) {
                        if (!element->isChord()) {
                            qDebug("cannot connect tremolo");
                            continue;
                        }
                        Chord* nc = toChord(element);
                        tremolo->setChords(c, nc);
                        nc->setTremolo(tremolo);
                        break;
                    }
                }
            }
        }
    }
}

//---------------------------------------------------------
//   createVoice
//    Create a voice on demand by filling the measure
//    with a whole measure rest.
//    Check if there are any chord/rests in track; if
//    not create a whole measure rest
//---------------------------------------------------------

void Measure::createVoice(int track)
{
    for (Segment* s = first(); s; s = s->next()) {
        if (s->segmentType() != SegmentType::ChordRest) {
            continue;
        }
        if (s->element(track) == 0) {
            score()->setRest(s->tick(), track, ticks(), true, 0);
        }
        break;
    }
}

//---------------------------------------------------------
//   sortStaves
//---------------------------------------------------------

void Measure::sortStaves(QList<int>& dst)
{
    std::vector<MStaff*> ms;
    for (int idx : dst) {
        ms.push_back(_mstaves[idx]);
    }
    _mstaves = ms;

    for (unsigned staffIdx = 0; staffIdx < _mstaves.size(); ++staffIdx) {
        _mstaves[staffIdx]->lines()->setTrack(staffIdx * VOICES);
    }
    for (Segment& s : _segments) {
        s.sortStaves(dst);
    }

    for (Element* e : el()) {
        if (e->track() == -1 || e->systemFlag()) {
            continue;
        }
        int voice    = e->voice();
        int staffIdx = e->staffIdx();
        int idx = dst.indexOf(staffIdx);
        e->setTrack(idx * VOICES + voice);
    }
}

//---------------------------------------------------------
//   exchangeVoice
//---------------------------------------------------------

void Measure::exchangeVoice(int strack, int dtrack, int staffIdx)
{
    for (Segment* s = first(SegmentType::ChordRest); s; s = s->next(SegmentType::ChordRest)) {
        s->swapElements(strack, dtrack);
    }

    auto spanners = score()->spannerMap().findOverlapping(tick().ticks(), endTick().ticks() - 1);
    Fraction start = tick();
    Fraction end = start + ticks();
    for (auto i = spanners.begin(); i < spanners.end(); i++) {
        Spanner* sp = i->value;
        Fraction spStart = sp->tick();
        Fraction spEnd = spStart + sp->ticks();
        qDebug("Start %d End %d Diff %d \n Measure Start %d End %d", spStart.ticks(),
               spEnd.ticks(), (spEnd - spStart).ticks(), start.ticks(), end.ticks());
        if (sp->isSlur() && (spStart >= start || spEnd < end)) {
            if (sp->track() == strack && spStart >= start) {
                sp->setTrack(dtrack);
            } else if (sp->track() == dtrack && spStart >= start) {
                sp->setTrack(strack);
            }
            if (sp->track2() == strack && spEnd < end) {
                sp->setTrack2(dtrack);
            } else if (sp->track2() == dtrack && spEnd < end) {
                sp->setTrack2(strack);
            }
        }
    }
    checkMultiVoices(staffIdx);     // probably true, but check for invisible notes & rests
}

//---------------------------------------------------------
//   checkMultiVoices
///   Check for more than on voice in this measure and staff and
///   set MStaff->hasVoices
//---------------------------------------------------------

void Measure::checkMultiVoices(int staffIdx)
{
    if (hasVoices(staffIdx, tick(), ticks())) {
        _mstaves[staffIdx]->setHasVoices(true);
    } else {
        _mstaves[staffIdx]->setHasVoices(false);
    }
}

//---------------------------------------------------------
//   hasVoices
//---------------------------------------------------------

bool Measure::hasVoices(int staffIdx, Fraction stick, Fraction len) const
{
    int strack = staffIdx * VOICES + 1;
    int etrack = staffIdx * VOICES + VOICES;
    Fraction etick = stick + len;

    for (Segment* s = first(SegmentType::ChordRest); s; s = s->next(SegmentType::ChordRest)) {
        if (s->tick() >= etick) {
            break;
        }
        for (int track = strack; track < etrack; ++track) {
            ChordRest* cr = toChordRest(s->element(track));
            if (cr) {
                if (cr->tick() + cr->actualTicks() <= stick) {
                    continue;
                }
                bool v = false;
                if (cr->isChord()) {
                    // consider chord visible if any note is visible
                    Chord* c = toChord(cr);
                    for (Note* n : c->notes()) {
                        if (n->visible()) {
                            v = true;
                            break;
                        }
                    }
                } else if (cr->isRest()) {
                    v = cr->visible() && !toRest(cr)->isGap();
                }
                if (v) {
                    return true;
                }
            }
        }
    }
    return false;
}

//---------------------------------------------------------
//   hasVoice
//---------------------------------------------------------

bool Measure::hasVoice(int track) const
{
    if (track >= score()->ntracks()) {
        return false;
    }
    for (Segment* s = first(); s; s = s->next()) {
        if (s->segmentType() != SegmentType::ChordRest) {
            continue;
        }
        if (s->element(track)) {
            return true;
        }
    }
    return false;
}

//-------------------------------------------------------------------
//   isEmpty
///   Check if the measure is filled by a full-measure rest, or is
///   full of rests on this staff, that may have fermatas on them.
///   If staff is -1, then check for all staves.
//-------------------------------------------------------------------

bool Measure::isEmpty(int staffIdx) const
{
    int strack;
    int etrack;
    if (staffIdx < 0) {
        strack = 0;
        etrack = score()->nstaves() * VOICES;
    } else {
        strack = staffIdx * VOICES;
        etrack = strack + VOICES;
    }
    for (Segment* s = first(SegmentType::ChordRest); s; s = s->next(SegmentType::ChordRest)) {
        for (int track = strack; track < etrack; ++track) {
            Element* e = s->element(track);
            if (e && !e->isRest()) {
                return false;
            }
        }
        for (Element* a : s->annotations()) {
            if (!a || a->systemFlag() || !a->visible() || a->isFermata()) {
                continue;
            }
            int atrack = a->track();
            if (atrack >= strack && atrack < etrack) {
                return false;
            }
        }
    }
    return true;
}

//---------------------------------------------------------
//   isFullMeasureRest
//    Check for an empty measure, filled with full measure
//    rests.
//---------------------------------------------------------

bool Measure::isFullMeasureRest() const
{
    int strack = 0;
    int etrack = score()->nstaves() * VOICES;

    Segment* s = first(SegmentType::ChordRest);
    for (int track = strack; track < etrack; ++track) {
        Element* e = s->element(track);
        if (e) {
            if (!e->isRest()) {
                return false;
            }
            Rest* rest = toRest(e);
            if (rest->durationType().type() != TDuration::DurationType::V_MEASURE) {
                return false;
            }
        }
    }
    return true;
}

//---------------------------------------------------------
//   isRepeatMeasure
//---------------------------------------------------------

bool Measure::isRepeatMeasure(const Staff* staff) const
{
    int staffIdx = staff->idx();
    int strack   = staffIdx * VOICES;
    int etrack   = (staffIdx + 1) * VOICES;
    Segment* s   = first(SegmentType::ChordRest);

    if (s == 0) {
        return false;
    }

    for (int track = strack; track < etrack; ++track) {
        Element* e = s->element(track);
        if (e && e->isRepeatMeasure()) {
            return true;
        }
    }
    return false;
}

//---------------------------------------------------------
//   isEmpty
//---------------------------------------------------------

bool Measure::empty() const
{
    if (irregular()) {
        return false;
    }
    int n = 0;
    int tracks = int(_mstaves.size()) * VOICES;
    static const SegmentType st = SegmentType::ChordRest;
    for (const Segment* s = first(st); s; s = s->next(st)) {
        bool restFound = false;
        for (int track = 0; track < tracks; ++track) {
            if ((track % VOICES) == 0 && !score()->staff(track / VOICES)->show()) {
                track += VOICES - 1;
                continue;
            }
            if (s->element(track)) {
                if (!s->element(track)->isRest()) {
                    return false;
                }
                restFound = true;
            }
        }
        if (restFound) {
            ++n;
        }
        // measure is not empty if there is more than one rest
        if (n > 1) {
            return false;
        }
    }
    return true;
}

//---------------------------------------------------------
//   isOnlyRests
//---------------------------------------------------------

bool Measure::isOnlyRests(int track) const
{
    static const SegmentType st = SegmentType::ChordRest;
    for (const Segment* s = first(st); s; s = s->next(st)) {
        if (s->segmentType() != st || !s->element(track)) {
            continue;
        }
        if (!s->element(track)->isRest()) {
            return false;
        }
    }
    return true;
}

//---------------------------------------------------------
//   isOnlyDeletedRests
//---------------------------------------------------------

bool Measure::isOnlyDeletedRests(int track) const
{
    static const SegmentType st { SegmentType::ChordRest };
    for (const Segment* s = first(st); s; s = s->next(st)) {
        if (s->segmentType() != st || !s->element(track)) {
            continue;
        }
        if (s->element(track)->isRest() ? !toRest(s->element(track))->isGap() : !s->element(track)->isRest()) {
            return false;
        }
    }
    return true;
}

//---------------------------------------------------------
//   stretchedLen
//---------------------------------------------------------

Fraction Measure::stretchedLen(Staff* staff) const
{
    return ticks() * staff->timeStretch(tick());
}

//---------------------------------------------------------
//   cloneMeasure
//---------------------------------------------------------

Measure* Measure::cloneMeasure(Score* sc, const Fraction& tick, TieMap* tieMap)
{
    Measure* m      = new Measure(sc);
    m->_timesig     = _timesig;
    m->_len         = _len;
    m->_repeatCount = _repeatCount;

    Q_ASSERT(sc->staves().size() >= int(_mstaves.size()));   // destination score we're cloning into must have at least as many staves as measure being cloned

    m->setNo(no());
    m->setNoOffset(noOffset());
    m->setIrregular(irregular());
    m->_userStretch           = _userStretch;
    m->_breakMultiMeasureRest = _breakMultiMeasureRest;
    m->_playbackCount         = _playbackCount;

    m->setTick(tick);
    m->setLineBreak(lineBreak());
    m->setPageBreak(pageBreak());
    m->setSectionBreak(sectionBreak() ? new LayoutBreak(*sectionBreakElement()) : 0);

    m->setHeader(header());
    m->setTrailer(trailer());

    int tracks = sc->nstaves() * VOICES;
    TupletMap tupletMap;

    for (Segment* oseg = first(); oseg; oseg = oseg->next()) {
        Segment* s = new Segment(m, oseg->segmentType(), oseg->rtick());
        s->setEnabled(oseg->enabled());
        s->setVisible(oseg->visible());
        s->setHeader(oseg->header());
        s->setTrailer(oseg->trailer());

        m->_segments.push_back(s);
        for (int track = 0; track < tracks; ++track) {
            Element* oe = oseg->element(track);
            for (Element* e : oseg->annotations()) {
                if (e->generated() || e->track() != track) {
                    continue;
                }
                Element* ne = e->clone();
                ne->setTrack(track);
                ne->setOffset(e->offset());
                ne->setScore(sc);
                s->add(ne);
            }
            if (!oe) {
                continue;
            }
            Element* ne = oe->clone();
            if (oe->isChordRest()) {
                ChordRest* ocr = toChordRest(oe);
                ChordRest* ncr = toChordRest(ne);
                Tuplet* ot     = ocr->tuplet();
                if (ot) {
                    Tuplet* nt = tupletMap.findNew(ot);
                    if (nt == 0) {
                        nt = new Tuplet(*ot);
                        nt->clear();
                        nt->setTrack(track);
                        nt->setScore(sc);
                        nt->setParent(m);
                        nt->setTick(m->tick() + ot->rtick());
                        tupletMap.add(ot, nt);
                    }
                    ncr->setTuplet(nt);
                    nt->add(ncr);
                }
                if (oe->isChord()) {
                    Chord* och = toChord(ocr);
                    Chord* nch = toChord(ncr);
                    size_t n = och->notes().size();
                    for (size_t i = 0; i < n; ++i) {
                        Note* on = och->notes().at(i);
                        Note* nn = nch->notes().at(i);
                        if (on->tieFor()) {
                            Tie* tie = on->tieFor()->clone();
                            tie->setScore(sc);
                            nn->setTieFor(tie);
                            tie->setStartNote(nn);
                            tieMap->add(on->tieFor(), tie);
                        }
                        if (on->tieBack()) {
                            Tie* tie = tieMap->findNew(on->tieBack());
                            if (tie) {
                                nn->setTieBack(tie);
                                tie->setEndNote(nn);
                            } else {
                                qDebug("cloneMeasure: cannot find tie, track %d", track);
                            }
                        }
                    }
                }
            }
            ne->setOffset(oe->offset());
            ne->setScore(sc);
            s->add(ne);
        }
    }
    for (Element* e : el()) {
        Element* ne = e->clone();
        ne->setScore(sc);
        ne->setOffset(e->offset());
        m->add(ne);
    }
    return m;
}

//---------------------------------------------------------
//   snap
//---------------------------------------------------------

Fraction Measure::snap(const Fraction& tick, const QPointF p) const
{
    Segment* s = first();
    for (; s->next(); s = s->next()) {
        qreal x  = s->x();
        qreal dx = s->next()->x() - x;
        if (s->tick() == tick) {
            x += dx / 3.0 * 2.0;
        } else if (s->next()->tick() == tick) {
            x += dx / 3.0;
        } else {
            x += dx * .5;
        }
        if (p.x() < x) {
            break;
        }
    }
    return s->tick();
}

//---------------------------------------------------------
//   snapNote
//---------------------------------------------------------

Fraction Measure::snapNote(const Fraction& /*tick*/, const QPointF p, int staff) const
{
    Segment* s = first();
    for (;;) {
        Segment* ns = s->next();
        while (ns && ns->element(staff) == 0) {
            ns = ns->next();
        }
        if (ns == 0) {
            break;
        }
        qreal x  = s->x();
        qreal nx = x + (ns->x() - x) * .5;
        if (p.x() < nx) {
            break;
        }
        s = ns;
    }
    return s->tick();
}

//---------------------------------------------------------
//   searchSegment
///   Finds a segment which x position is most close to the
///   given \p x.
///   \param x The x coordinate in measure coordinates.
///   \param st Type of segments to search.
///   \param strack start of track range (strack included)
///   in which the found segment should contain elements.
///   \param etrack end of track range (etrack excluded)
///   in which the found segment should contain elements.
///   \param preferredSegment If not nullptr, will give
///   more space to the given segment when searching it by
///   coordinate.
///   \returns The segment that was found.
//---------------------------------------------------------

Segment* Measure::searchSegment(qreal x, SegmentType st, int strack, int etrack, const Segment* preferredSegment,
                                qreal spacingFactor) const
{
    const int lastTrack = etrack - 1;
    for (Segment* segment = first(st); segment; segment = segment->next(st)) {
        if (!segment->hasElements(strack, lastTrack)) {
            continue;
        }
        Segment* ns = segment->next(st);
        for (; ns; ns = ns->next(st)) {
            if (ns->hasElements(strack, lastTrack)) {
                break;
            }
        }
        if (!ns) {
            return segment;
        }
        if (preferredSegment == segment) {
            if (x < (segment->x() + (ns->x() - segment->x()))) {
                return segment;
            }
        } else if (preferredSegment == ns) {
            if (x <= segment->x()) {
                return segment;
            }
        } else {
            if (x < (segment->x() + (ns->x() - segment->x()) * spacingFactor)) {
                return segment;
            }
        }
    }
    return nullptr;
}

//---------------------------------------------------------
//   getProperty
//---------------------------------------------------------

QVariant Measure::getProperty(Pid propertyId) const
{
    switch (propertyId) {
    case Pid::TIMESIG_NOMINAL:
        return QVariant::fromValue(_timesig);
    case Pid::TIMESIG_ACTUAL:
        return QVariant::fromValue(_len);
    case Pid::MEASURE_NUMBER_MODE:
        return int(measureNumberMode());
    case Pid::BREAK_MMR:
        return breakMultiMeasureRest();
    case Pid::REPEAT_COUNT:
        return repeatCount();
    case Pid::USER_STRETCH:
        return userStretch();
    default:
        return MeasureBase::getProperty(propertyId);
    }
}

//---------------------------------------------------------
//   setProperty
//---------------------------------------------------------

bool Measure::setProperty(Pid propertyId, const QVariant& value)
{
    switch (propertyId) {
    case Pid::TIMESIG_NOMINAL:
        _timesig = value.value<Fraction>();
        break;
    case Pid::TIMESIG_ACTUAL:
        _len = value.value<Fraction>();
        break;
    case Pid::MEASURE_NUMBER_MODE:
        setMeasureNumberMode(MeasureNumberMode(value.toInt()));
        break;
    case Pid::BREAK_MMR:
        setBreakMultiMeasureRest(value.toBool());
        break;
    case Pid::REPEAT_COUNT:
        setRepeatCount(value.toInt());
        break;
    case Pid::USER_STRETCH:
        setUserStretch(value.toDouble());
        break;
    default:
        return MeasureBase::setProperty(propertyId, value);
    }
    triggerLayout();
    return true;
}

//---------------------------------------------------------
//   propertyDefault
//---------------------------------------------------------

QVariant Measure::propertyDefault(Pid propertyId) const
{
    switch (propertyId) {
    case Pid::TIMESIG_NOMINAL:
    case Pid::TIMESIG_ACTUAL:
        return QVariant();
    case Pid::MEASURE_NUMBER_MODE:
        return int(MeasureNumberMode::AUTO);
    case Pid::BREAK_MMR:
        return false;
    case Pid::REPEAT_COUNT:
        return 2;
    case Pid::USER_STRETCH:
        return 1.0;
    case Pid::NO_OFFSET:
        return 0;
    case Pid::IRREGULAR:
        return false;
    default:
        break;
    }
    return MeasureBase::propertyDefault(propertyId);
}

//-------------------------------------------------------------------
//   mmRestFirst
//    this is a multi measure rest
//    returns first measure of replaced sequence of empty measures
//-------------------------------------------------------------------

Measure* Measure::mmRestFirst() const
{
    Q_ASSERT(isMMRest());
    if (prev()) {
        return toMeasure(prev()->next());
    }
    return score()->firstMeasure();
}

//-------------------------------------------------------------------
//   mmRestLast
//    this is a multi measure rest
//    returns last measure of replaced sequence of empty measures
//-------------------------------------------------------------------

Measure* Measure::mmRestLast() const
{
    Q_ASSERT(isMMRest());
    if (next()) {
        return toMeasure(next()->prev());
    }
    return score()->lastMeasure();
}

//---------------------------------------------------------
//   mmRest1
//    return the multi measure rest this measure is covered
//    by
//---------------------------------------------------------

const Measure* Measure::mmRest1() const
{
    if (_mmRest) {
        return _mmRest;
    }
    if (_mmRestCount != -1) {
        // return const_cast<Measure*>(this);
        return this;
    }
    const Measure* m = this;
    while (m && !m->_mmRest) {
        m = m->prevMeasure();
    }
    if (m) {
        return const_cast<Measure*>(m->_mmRest);
    }
    return 0;
}

//-------------------------------------------------------------------
//   userStretch
//-------------------------------------------------------------------

qreal Measure::userStretch() const
{
    return score()->layoutMode() == LayoutMode::FLOAT ? 1.0 : _userStretch;
}

//---------------------------------------------------------
//   nextElementStaff
//---------------------------------------------------------

Element* Measure::nextElementStaff(int staff)
{
    Element* e = score()->selection().element();
    if (!e && !score()->selection().elements().isEmpty()) {
        e = score()->selection().elements().first();
    }

    // handle measure elements
    if (e->parent() == this) {
        auto i = std::find(el().begin(), el().end(), e);
        if (i != el().end()) {
            if (++i != el().end()) {
                Element* resElement = *i;
                if (resElement) {
                    return resElement;
                }
            }
        }
    }

    for (; e && e->type() != ElementType::SEGMENT; e = e->parent()) {
    }
    Segment* seg = toSegment(e);
    Segment* nextSegment = seg ? seg->next() : first();
    Element* next = seg->firstElementOfSegment(nextSegment, staff);
    if (next) {
        return next;
    }

    return score()->lastElement();
}

//---------------------------------------------------------
//   prevElementStaff
//---------------------------------------------------------

Element* Measure::prevElementStaff(int staff)
{
    Element* e = score()->selection().element();
    if (!e && !score()->selection().elements().isEmpty()) {
        e = score()->selection().elements().first();
    }

    // handle measure elements
    if (e->parent() == this) {
        auto i = std::find(el().rbegin(), el().rend(), e);
        if (i != el().rend()) {
            if (++i != el().rend()) {
                Element* resElement = *i;
                if (resElement) {
                    return resElement;
                }
            }
        }
    }

    Measure* prevM = prevMeasureMM();
    if (prevM) {
        Segment* seg = prevM->last();
        if (seg) {
            return seg->lastElement(staff);
        }
    }
    return score()->firstElement();
}

//---------------------------------------------------------
//   accessibleInfo
//---------------------------------------------------------

QString Measure::accessibleInfo() const
{
    return QString("%1: %2").arg(Element::accessibleInfo()).arg(QString::number(no() + 1));
}

//-----------------------------------------------------------------------------
//    stretchMeasure
//    resize width of measure to targetWidth
//-----------------------------------------------------------------------------

void Measure::stretchMeasure(qreal targetWidth)
{
    bbox().setWidth(targetWidth);

    Fraction minTick = computeTicks();

    //---------------------------------------------------
    //    compute stretch
    //---------------------------------------------------

    std::multimap<qreal, Segment*> springs;

    Segment* seg = first();
    while (seg && !seg->enabled()) {
        seg = seg->next();
    }
    qreal minimumWidth = seg ? seg->x() : 0.0;
    for (Segment& s : _segments) {
        if (!s.enabled() || !s.visible()) {
            continue;
        }
        Fraction t = s.ticks();
        if (t.isNotZero()) {
            qreal str = 1.0 + 0.865617 * log(qreal(t.ticks()) / qreal(minTick.ticks()));       // .6 * log(t / minTick.ticks()) / log(2);
            qreal d   = s.width() / str;
            s.setStretch(str);
            springs.insert(std::pair<qreal, Segment*>(d, &s));
        }
        minimumWidth += s.width();
    }

    //---------------------------------------------------
    //    compute 1/Force for a given Extend
    //---------------------------------------------------

    if (targetWidth > minimumWidth) {
        qreal force = 0;
        qreal c     = 0.0;
        for (auto i = springs.begin(); i != springs.end();) {
            c            += i->second->stretch();
            minimumWidth -= i->second->width();
            qreal f       = (targetWidth - minimumWidth) / c;
            ++i;
            if (i == springs.end() || f <= i->first) {
                force = f;
                break;
            }
        }

        //---------------------------------------------------
        //    distribute stretch to segments
        //---------------------------------------------------

        for (auto& i : springs) {
            qreal width = force * i.second->stretch();
            if (width > i.second->width()) {
                i.second->setWidth(width);
            }
        }

        //---------------------------------------------------
        //    move segments to final position
        //---------------------------------------------------

        Segment* s = first();
        while (s && !s->enabled()) {
            s = s->next();
        }
        qreal x = s->pos().x();
        while (s) {
            s->rxpos() = x;
            x += s->width();
            s = s->nextEnabled();
        }
    }

    //---------------------------------------------------
    //    layout individual elements
    //---------------------------------------------------

    for (Segment& s : _segments) {
        if (!s.enabled()) {
            continue;
        }
        for (Element* e : s.elist()) {
            if (!e) {
                continue;
            }
            ElementType t = e->type();
            int staffIdx    = e->staffIdx();
            if (t == ElementType::REPEAT_MEASURE
                || (t == ElementType::REST && (isMMRest() || toRest(e)->isFullMeasureRest()))) {
                //
                // element has to be centered in free space
                //    x1 - left measure position of free space
                //    x2 - right measure position of free space

                Segment* s1;
                for (s1 = s.prev(); s1 && !s1->enabled(); s1 = s1->prev()) {
                }
                Segment* s2;
                for (s2 = s.next(); s2; s2 = s2->next()) {
                    if (s2->enabled() && !s2->isChordRestType() && s2->element(staffIdx * VOICES)) {
                        break;
                    }
                }
                qreal x1 = s1 ? s1->x() + s1->minRight() : 0;
                qreal x2 = s2 ? s2->x() - s2->minLeft() : targetWidth;

                if (isMMRest()) {
                    Rest* rest = toRest(e);
                    //
                    // center multi measure rest
                    //
                    qreal d = score()->styleP(Sid::multiMeasureRestMargin);
                    qreal w = x2 - x1 - 2 * d;

                    rest->layoutMMRest(w);
                    e->setPos(x1 - s.x() + d, e->staff()->height() * .5);             // center vertically in measure
                    s.createShape(staffIdx);
                } else {       // if (rest->isFullMeasureRest()) {
                    //
                    // center full measure rest
                    //
                    e->rxpos() = (x2 - x1 - e->width()) * .5 + x1 - s.x() - e->bbox().x();
                    s.createShape(staffIdx);            // DEBUG
                }
            } else if (t == ElementType::REST) {
                e->rxpos() = 0;
            } else if (t == ElementType::CHORD) {
                Chord* c = toChord(e);
                c->layout2();
                if (c->tremolo()) {
                    Tremolo* tr = c->tremolo();
                    Chord* c1 = tr->chord1();
                    Chord* c2 = tr->chord2();
                    if (!tr->twoNotes() || (c1 && !c1->staffMove() && c2 && !c2->staffMove())) {
                        tr->layout();
                    }
                }
            } else if (t == ElementType::BAR_LINE) {
                e->rypos() = 0.0;
                // for end barlines, x position was set in createEndBarLines
                if (s.segmentType() != SegmentType::EndBarLine) {
                    e->rxpos() = 0.0;
                }
            }
        }
    }
}

//---------------------------------------------------
//    computeTicks
//    set ticks for all segments
//       return minTick
//---------------------------------------------------

Fraction Measure::computeTicks()
{
    Fraction minTick = ticks();
    if (minTick <= Fraction(0,1)) {
        qDebug("=====minTick %d measure %p", minTick.ticks(), this);
    }
    Q_ASSERT(minTick > Fraction(0,1));

    Segment* ns = first();
    while (ns && !ns->enabled()) {
        ns = ns->next();
    }
    while (ns) {
        Segment* s = ns;
        ns         = s->nextActive();
        Fraction nticks = (ns ? ns->rtick() : ticks()) - s->rtick();
        if (nticks.isNotZero()) {
            if (nticks < minTick) {
                minTick = nticks;
            }
        }
        s->setTicks(nticks);
    }
    return minTick;
}

//---------------------------------------------------------
//   endBarLine
//      return the first one
//---------------------------------------------------------

const BarLine* Measure::endBarLine() const
{
    // search barline segment:
    Segment* s = last();
    while (s && !s->isEndBarLineType()) {
        s = s->prev();
    }
    // search first element
    if (s) {
        for (const Element* e : s->elist()) {
            if (e) {
                return toBarLine(e);
            }
        }
    }
    return 0;
}

//---------------------------------------------------------
//   endBarLineType
//    Assume all barlines have same type if there is more
//    than one.
//---------------------------------------------------------

BarLineType Measure::endBarLineType() const
{
    const BarLine* bl = endBarLine();
    return bl ? bl->barLineType() : BarLineType::NORMAL;
}

//---------------------------------------------------------
//   endBarLineType
//    Assume all barlines have same visibility if there is more
//    than one.
//---------------------------------------------------------

bool Measure::endBarLineVisible() const
{
    const BarLine* bl = endBarLine();
    return bl ? bl->visible() : true;
}

//---------------------------------------------------------
//   triggerLayout
//---------------------------------------------------------

void Measure::triggerLayout() const
{
    if (prev() || next()) { // avoid triggering layout before getting added to a score
        score()->setLayout(tick(), endTick(), 0, score()->nstaves() - 1, this);
    }
}

//---------------------------------------------------------
//   setEndBarLineType
//     Create a *generated* barline with the given type and
//     properties if none exists. Modify if it exists.
//     Useful for import filters.
//---------------------------------------------------------

void Measure::setEndBarLineType(BarLineType val, int track, bool visible, QColor color)
{
    Segment* seg = undoGetSegment(SegmentType::EndBarLine, endTick());
    // get existing bar line for this staff, if any
    BarLine* bl = toBarLine(seg->element(track));
    if (!bl) {
        // no suitable bar line: create a new one
        bl = new BarLine(score());
        bl->setParent(seg);
        bl->setTrack(track);
        score()->addElement(bl);
    }
    bl->setGenerated(false);
    bl->setBarLineType(val);
    bl->setVisible(visible);
    bl->setColor(color.isValid() ? color : curColor());
}

//---------------------------------------------------------
//   barLinesSetSpan
//---------------------------------------------------------

void Measure::barLinesSetSpan(Segment* seg)
{
    int track = 0;
    for (Staff* staff : score()->staves()) {
        BarLine* bl = toBarLine(seg->element(track));      // get existing bar line for this staff, if any
        if (bl) {
            if (bl->generated()) {
                bl->setSpanStaff(staff->barLineSpan());
                bl->setSpanFrom(staff->barLineFrom());
                bl->setSpanTo(staff->barLineTo());
            }
        } else {
            bl = new BarLine(score());
            bl->setParent(seg);
            bl->setTrack(track);
            bl->setGenerated(true);
            bl->setSpanStaff(staff->barLineSpan());
            bl->setSpanFrom(staff->barLineFrom());
            bl->setSpanTo(staff->barLineTo());
            bl->layout();
            score()->addElement(bl);
        }
        track += VOICES;
    }
}

//---------------------------------------------------------
//   createEndBarLines
//    actually creates or modifies barlines
//    return the width change for measure
//---------------------------------------------------------

qreal Measure::createEndBarLines(bool isLastMeasureInSystem)
{
    int nstaves  = score()->nstaves();
    Segment* seg = findSegmentR(SegmentType::EndBarLine, ticks());
    Measure* nm  = nextMeasure();
    qreal blw    = 0.0;

#if 0
#ifndef NDEBUG
    computeMinWidth();
#endif
#endif
    qreal oldWidth = width();

    if (nm && nm->repeatStart() && !repeatEnd() && !isLastMeasureInSystem && next() == nm) {
        // we may skip barline at end of a measure immediately before a start repeat:
        // next measure is repeat start, this measure is not a repeat end,
        // this is not last measure of system, no intervening frame
        if (!seg) {
            return 0.0;
        }
        seg->setEnabled(false);
    } else {
        BarLineType t = nm ? BarLineType::NORMAL : BarLineType::END;
        if (!seg) {
            seg = getSegmentR(SegmentType::EndBarLine, ticks());
        }
        seg->setEnabled(true);
        //
        //  Set flag "hasCourtesyKeySig" if this measure needs a courtesy key sig.
        //  This flag is later used to set a double end bar line and to actually
        //  create the courtesy key sig.
        //

        bool show = score()->styleB(Sid::genCourtesyKeysig) && !sectionBreak() && nm;

        setHasCourtesyKeySig(false);

        if (isLastMeasureInSystem && show) {
            Fraction tick = endTick();
            for (int staffIdx = 0; staffIdx < nstaves; ++staffIdx) {
                Staff* staff     = score()->staff(staffIdx);
                KeySigEvent key1 = staff->keySigEvent(tick - Fraction::fromTicks(1));
                KeySigEvent key2 = staff->keySigEvent(tick);
                if (!(key1 == key2)) {
                    // locate a key sig. in next measure and, if found,
                    // check if it has court. sig turned off
                    Segment* s = nm->findSegment(SegmentType::KeySig, tick);
                    if (s) {
                        KeySig* ks = toKeySig(s->element(staffIdx * VOICES));
                        if (ks && !ks->showCourtesy()) {
                            continue;
                        }
                    }
                    setHasCourtesyKeySig(true);
                    t = BarLineType::DOUBLE;
                    break;
                }
            }
        }

        bool force = false;
        if (repeatEnd()) {
            t = BarLineType::END_REPEAT;
            force = true;
        } else if (isLastMeasureInSystem && nextMeasure() && nextMeasure()->repeatStart()) {
            t = BarLineType::NORMAL;
//                  force = true;
        }

        for (int staffIdx = 0; staffIdx < nstaves; ++staffIdx) {
            int track    = staffIdx * VOICES;
            BarLine* bl  = toBarLine(seg->element(track));
            Staff* staff = score()->staff(staffIdx);
            if (!bl) {
                bl = new BarLine(score());
                bl->setParent(seg);
                bl->setTrack(track);
                bl->setGenerated(true);
                bl->setSpanStaff(staff->barLineSpan());
                bl->setSpanFrom(staff->barLineFrom());
                bl->setSpanTo(staff->barLineTo());
                bl->setBarLineType(t);
                score()->addElement(bl);
            } else {
                // do not change bar line type if bar line is user modified
                // and its not a repeat start/end barline (forced)

                if (bl->generated()) {
                    bl->setSpanStaff(staff->barLineSpan());
                    bl->setSpanFrom(staff->barLineFrom());
                    bl->setSpanTo(staff->barLineTo());
                    bl->setBarLineType(t);
                } else {
                    if (bl->barLineType() != t) {
                        if (force) {
                            bl->undoChangeProperty(Pid::BARLINE_TYPE, QVariant::fromValue(t));
                            bl->setGenerated(true);
                        }
                    }
                }
            }
            bl->layout();
            blw = qMax(blw, bl->width());
        }
        // right align within segment
        for (int staffIdx = 0; staffIdx < nstaves; ++staffIdx) {
            int track   = staffIdx * VOICES;
            BarLine* bl = toBarLine(seg->element(track));
            if (bl) {
                bl->rxpos() += blw - bl->width();
            }
        }
        seg->createShapes();
    }

    // set relative position of end barline and clef
    // if end repeat, clef goes after, otherwise clef goes before
    Segment* clefSeg = findSegmentR(SegmentType::Clef, ticks());
    if (clefSeg) {
        bool wasVisible = clefSeg->visible();
        int visibleInt = 0;
        for (int staffIdx = 0; staffIdx < nstaves; ++staffIdx) {
            int track    = staffIdx * VOICES;
            Clef* clef = toClef(clefSeg->element(track));
            if (clef) {
                bool showCourtesy = score()->genCourtesyClef() && clef->showCourtesy();         // normally show a courtesy clef
                // check if the measure is the last measure of the system or the last measure before a frame
                bool lastMeasure = isLastMeasureInSystem || (nm ? !(next() == nm) : true);
                if (!nm || isFinalMeasureOfSection() || (lastMeasure && !showCourtesy)) {
                    // hide the courtesy clef in the final measure of a section, or if the measure is the final measure of a system
                    // and the score style or the clef style is set to "not show courtesy clef",
                    // or if the clef is at the end of the very last measure of the score
                    clef->clear();
                    clefSeg->createShape(staffIdx);
                    if (visibleInt == 0) {
                        visibleInt = 1;
                    }
                } else {
                    clef->layout();
                    clefSeg->createShape(staffIdx);
                    visibleInt = 2;
                }
            }
        }
        if (visibleInt == 2) {         // there is at least one visible clef in the clef segment
            clefSeg->setVisible(true);
        } else if (visibleInt == 1) {  // all (courtesy) clefs in the clef segment are not visible
            clefSeg->setVisible(false);
        } else { // should never happen
            qDebug("Clef Segment without Clef elements at tick %d/%d",clefSeg->tick().numerator(),
                   clefSeg->tick().denominator());
        }
        if ((wasVisible != clefSeg->visible()) && system()) {   // recompute the width only if necessary
            computeMinWidth();
        }
        if (seg) {
            Segment* s1;
            Segment* s2;
            if (repeatEnd()) {
                s1 = seg;
                s2 = clefSeg;
            } else {
                s1 = clefSeg;
                s2 = seg;
            }
            if (s1->next() != s2) {
                _segments.remove(s1);
                _segments.insert(s1, s2);
            }
        }
    }

    // fix segment layout
    Segment* s = seg->prevActive();
    if (s) {
        qreal x    = s->rxpos();
        computeMinWidth(s, x, false);
    }

#if 0
#ifndef NDEBUG
    qreal w = width();
    computeMinWidth();
    if (!qFuzzyCompare(w, width())) {
        qDebug("width mismatch %f != %f at %d", w, width(), tick());
    }
#endif
#endif
    return width() - oldWidth;
}

//---------------------------------------------------------
//   basicStretch
//---------------------------------------------------------

qreal Measure::basicStretch() const
{
    qreal stretch = userStretch() * score()->styleD(Sid::measureSpacing);
    if (stretch < 1.0) {
        stretch = 1.0;
    }
    return stretch;
}

//---------------------------------------------------------
//   basicWidth
//---------------------------------------------------------

qreal Measure::basicWidth() const
{
    Segment* ls = last();
    qreal w = (ls->x() + ls->width()) * basicStretch();
    qreal minMeasureWidth = score()->styleP(Sid::minMeasureWidth);
    if (w < minMeasureWidth) {
        w = minMeasureWidth;
    }
    return w;
}

//---------------------------------------------------------
//   layoutWeight
//---------------------------------------------------------

int Measure::layoutWeight(int maxMMRestLength) const
{
    int w = ticks().ticks();
    // reduce weight of mmrests
    // so the nominal width is not directly proportional to duration (still linear, just not 1:1)
    // and they are not so "greedy" in taking up available space on a system
    if (isMMRest()) {
        int timesigTicks = timesig().ticks();
        // TODO: style setting
        if (maxMMRestLength) {
            int maxW = timesigTicks * maxMMRestLength;
            w = qMin(w, maxW);
        }
        w -= timesigTicks;
        w = timesigTicks + w / 32;
    }
    return w;
}

//-------------------------------------------------------------------
//   addSystemHeader
///   Add elements to make this measure suitable as the first measure
///   of a system.
//    The system header can contain a starting BarLine, a Clef,
//    and a KeySig
//-------------------------------------------------------------------

void Measure::addSystemHeader(bool isFirstSystem)
{
    int staffIdx = 0;
    Segment* kSegment = findFirstR(SegmentType::KeySig, Fraction(0,1));
    Segment* cSegment = findFirstR(SegmentType::HeaderClef, Fraction(0,1));

    for (const Staff* staff : score()->staves()) {
        const int track = staffIdx * VOICES;

        if (isFirstSystem || score()->styleB(Sid::genClef)) {
            // find the clef type at the previous tick
            ClefTypeList cl = staff->clefType(tick() - Fraction::fromTicks(1));
            Segment* s = nullptr;
            if (prevMeasure()) {
                // look for a clef change at the end of the previous measure
                s = prevMeasure()->findSegment(SegmentType::Clef, tick());
            } else if (isMMRest()) {
                // look for a header clef at the beginning of the first underlying measure
                s = mmRestFirst()->findFirstR(SegmentType::HeaderClef, Fraction(0,1));
            }
            if (s) {
                Clef* c = toClef(s->element(track));
                if (c) {
                    cl = c->clefTypeList();
                }
            }
            Clef* clef;
            if (!cSegment) {
                cSegment = new Segment(this, SegmentType::HeaderClef, Fraction(0,1));
                cSegment->setHeader(true);
                add(cSegment);
                clef = 0;
            } else {
                clef = toClef(cSegment->element(track));
            }
            if (staff->staffType(tick())->genClef()) {
                if (!clef) {
                    //
                    // create missing clef
                    //
                    clef = new Clef(score());
                    clef->setTrack(track);
                    clef->setGenerated(true);
                    clef->setParent(cSegment);
                    cSegment->add(clef);
                }
                if (clef->generated()) {
                    clef->setClefType(cl);
                }
                clef->setSmall(false);
                clef->layout();
            } else if (clef) {
                clef->parent()->remove(clef);
                delete clef;
            }
            //cSegment->createShape(staffIdx);
            cSegment->setEnabled(true);
        } else {
            if (cSegment) {
                cSegment->setEnabled(false);
            }
        }

        // keep key sigs in TABs: TABs themselves should hide them
        bool needKeysig = isFirstSystem || score()->styleB(Sid::genKeysig);

        // If we need a Key::C KeySig (which would be invisible) and there is
        // a courtesy key sig, don’t create it and switch generated flags.
        // This avoids creating an invisible KeySig which can distort layout.

        KeySigEvent keyIdx = staff->keySigEvent(tick());
        KeySig* ksAnnounce = 0;
        if (needKeysig && (keyIdx.key() == Key::C)) {
            Measure* pm = prevMeasure();
            if (pm && pm->hasCourtesyKeySig()) {
                Segment* ks = pm->first(SegmentType::KeySigAnnounce);
                if (ks) {
                    ksAnnounce = toKeySig(ks->element(track));
                    if (ksAnnounce) {
                        needKeysig = false;
//                                    if (keysig) {
//                                          ksAnnounce->setGenerated(false);
//TODO                                      keysig->setGenerated(true);
//                                          }
                    }
                }
            }
        }

        needKeysig = needKeysig && (keyIdx.key() != Key::C || keyIdx.custom() || keyIdx.isAtonal());

        if (needKeysig) {
            KeySig* keysig;
            if (!kSegment) {
                kSegment = new Segment(this, SegmentType::KeySig, Fraction(0,1));
                kSegment->setHeader(true);
                add(kSegment);
                keysig = 0;
            } else {
                keysig  = toKeySig(kSegment->element(track));
            }
            if (!keysig) {
                //
                // create missing key signature
                //
                keysig = new KeySig(score());
                keysig->setTrack(track);
                keysig->setGenerated(true);
                keysig->setParent(kSegment);
                kSegment->add(keysig);
            }
            keysig->setKeySigEvent(keyIdx);
            keysig->layout();
            //kSegment->createShape(staffIdx);
            kSegment->setEnabled(true);
        } else {
            if (kSegment && staff->isPitchedStaff(tick())) {
                // do not disable user modified keysigs
                bool disable = true;
                for (int i = 0; i < score()->nstaves(); ++i) {
                    Element* e = kSegment->element(i * VOICES);
                    Key key = score()->staff(i)->key(tick());
                    if ((e && !e->generated()) || (key != keyIdx.key())) {
                        disable = false;
                    } else if (e && e->generated() && key == keyIdx.key() && keyIdx.key() == Key::C) {
                        // If a key sig segment is disabled, it may be re-enabled if there is
                        // a transposing instrument using a different key sig.
                        // To prevent this from making the wrong key sig display, remove any key
                        // sigs on staves where the key in this measure is C.
                        kSegment->remove(e);
                    }
                }

                if (disable) {
                    kSegment->setEnabled(false);
                } else {
                    Element* e = kSegment->element(track);
                    if (e && e->isKeySig()) {
                        KeySig* keysig = toKeySig(e);
                        keysig->layout();
                    }
                }
            }
        }

        ++staffIdx;
    }
    if (cSegment) {
        cSegment->createShapes();
    }
    if (kSegment) {
        kSegment->createShapes();
    }

    //
    // create systemic barline
    //
    Segment* s  = findSegment(SegmentType::BeginBarLine, tick());
    int n       = score()->nstaves();
    if ((n > 1 && score()->styleB(Sid::startBarlineMultiple)) || (n == 1 && score()->styleB(Sid::startBarlineSingle))) {
        if (!s) {
            s = new Segment(this, SegmentType::BeginBarLine, Fraction(0,1));
            add(s);
        }
        for (int track = 0; track < score()->ntracks(); track += VOICES) {
            BarLine* bl = toBarLine(s->element(track));
            if (!bl) {
                bl = new BarLine(score());
                bl->setTrack(track);
                bl->setGenerated(true);
                bl->setParent(s);
                bl->setBarLineType(BarLineType::NORMAL);
                bl->setSpanStaff(true);
                bl->layout();
                s->add(bl);
            }
        }
        s->createShapes();
        s->setEnabled(true);
        s->setHeader(true);
        setHeader(true);
    } else if (s) {
        s->setEnabled(false);
    }
    checkHeader();
}

//---------------------------------------------------------
//   addSystemTrailer
//---------------------------------------------------------

void Measure::addSystemTrailer(Measure* nm)
{
    Fraction _rtick = ticks();
    bool isFinalMeasure = isFinalMeasureOfSection();

    // locate a time sig. in the next measure and, if found,
    // check if it has court. sig. turned off
    TimeSig* ts = nullptr;
    bool showCourtesySig = false;
    Segment* s = findSegmentR(SegmentType::TimeSigAnnounce, _rtick);
    if (nm && score()->genCourtesyTimesig() && !isFinalMeasure && !score()->floatMode()) {
        Segment* tss = nm->findSegmentR(SegmentType::TimeSig, Fraction(0,1));
        if (tss) {
            int nstaves = score()->nstaves();
            for (int track = 0; track < nstaves * VOICES; track += VOICES) {
                ts = toTimeSig(tss->element(track));
                if (ts) {
                    break;
                }
            }
            if (ts && ts->showCourtesySig()) {
                showCourtesySig = true;
                // if due, create a new courtesy time signature for each staff
                if (!s) {
                    s  = new Segment(this, SegmentType::TimeSigAnnounce, _rtick);
                    s->setTrailer(true);
                    add(s);
                }
                s->setEnabled(true);
                for (int track = 0; track < nstaves * VOICES; track += VOICES) {
                    TimeSig* nts = toTimeSig(tss->element(track));
                    if (!nts) {
                        continue;
                    }
                    ts = toTimeSig(s->element(track));
                    if (!ts) {
                        ts = new TimeSig(score());
                        ts->setTrack(track);
                        ts->setGenerated(true);
                        ts->setParent(s);
                        score()->undoAddElement(ts);
                    }
                    ts->setFrom(nts);
                    ts->layout();
                    //s->createShape(track / VOICES);
                }
                s->createShapes();
            }
        }
    }
    if (!showCourtesySig && s) {
        // remove any existing time signatures
        s->setEnabled(false);
    }

    // courtesy key signatures, clefs

    int n      = score()->nstaves();
    bool show  = hasCourtesyKeySig();
    s          = findSegmentR(SegmentType::KeySigAnnounce, _rtick);

    Segment* clefSegment = findSegmentR(SegmentType::Clef, ticks());

    for (int staffIdx = 0; staffIdx < n; ++staffIdx) {
        int track    = staffIdx * VOICES;
        Staff* staff = score()->staff(staffIdx);

        if (show) {
            if (!s) {
                s = new Segment(this, SegmentType::KeySigAnnounce, _rtick);
                s->setTrailer(true);
                add(s);
            }
            KeySig* ks = toKeySig(s->element(track));
            KeySigEvent key2 = staff->keySigEvent(endTick());

            if (!ks) {
                ks = new KeySig(score());
                ks->setTrack(track);
                ks->setGenerated(true);
                ks->setParent(s);
                s->add(ks);
            }
            //else if (!(ks->keySigEvent() == key2)) {
            //      score()->undo(new ChangeKeySig(ks, key2, ks->showCourtesy()));
            //      }
            ks->setKeySigEvent(key2);
            ks->layout();
            //s->createShape(track / VOICES);
            s->setEnabled(true);
        } else {
            // remove any existent courtesy key signature
            if (s) {
                s->setEnabled(false);
            }
        }
        if (clefSegment) {
            Clef* clef = toClef(clefSegment->element(track));
            if (clef) {
                clef->setSmall(true);
            }
        }
    }
    if (s) {
        s->createShapes();
    }
    if (clefSegment) {
        clefSegment->createShapes();
    }

    checkTrailer();
}

//---------------------------------------------------------
//   removeSystemHeader
//---------------------------------------------------------

void Measure::removeSystemHeader()
{
    if (!header()) {
        return;
    }
    for (Segment* seg = first(); seg; seg = seg->next()) {
        if (!seg->header()) {
            break;
        }
        seg->setEnabled(false);
    }
    setHeader(false);
}

//---------------------------------------------------------
//   removeSystemTrailer
//---------------------------------------------------------

void Measure::removeSystemTrailer()
{
    bool changed = false;
    for (Segment* seg = last(); seg != first(); seg = seg->prev()) {
        if (!seg->trailer()) {
            break;
        }
        if (seg->enabled()) {
            seg->setEnabled(false);
        }
        changed = true;
    }
    setTrailer(false);
    if (system() && changed) {
        computeMinWidth();
    }
}

//---------------------------------------------------------
//   checkHeader
//---------------------------------------------------------

void Measure::checkHeader()
{
    for (Segment* seg = first(); seg; seg = seg->next()) {
        if (seg->enabled() && seg->header()) {
            setHeader(seg->header());
            break;
        }
    }
}

//---------------------------------------------------------
//   checkTrailer
//---------------------------------------------------------

void Measure::checkTrailer()
{
    for (Segment* seg = last(); seg != first(); seg = seg->prev()) {
        if (seg->enabled() && seg->trailer()) {
            setTrailer(seg->trailer());
            break;
        }
    }
}

//---------------------------------------------------------
//   setStretchedWidth
//---------------------------------------------------------

void Measure::setStretchedWidth(qreal w)
{
    qreal minWidth = isMMRest() ? score()->styleP(Sid::minMMRestWidth) : score()->styleP(Sid::minMeasureWidth);
    if (w < minWidth) {
        w = minWidth;
    }

    qreal stretchableWidth = 0.0;
    for (Segment* s = first(SegmentType::ChordRest); s; s = s->next(SegmentType::ChordRest)) {
        if (!s->enabled()) {
            continue;
        }
        stretchableWidth += s->width();
    }
    const int maxMMRestLength = 32;       // TODO: style
    int weight = layoutWeight(maxMMRestLength);
    w += stretchableWidth * (basicStretch() - 1.0) * weight / 1920.0;

    setWidth(w);
}

//---------------------------------------------------------
//   hasAccidental
//---------------------------------------------------------

static bool hasAccidental(Segment* s)
{
    Score* score = s->score();
    for (int track = 0; track < s->score()->ntracks(); ++track) {
        Staff* staff = score->staff(track2staff(track));
        if (!staff->show()) {
            continue;
        }
        Element* e = s->element(track);
        if (!e || !e->isChord()) {
            continue;
        }
        Chord* c = toChord(e);
        for (Note* n : c->notes()) {
            if (n->accidental()) {
                return true;
            }
        }
    }
    return false;
}

//---------------------------------------------------------
//   computeMinWidth
//    sets the minimum stretched width of segment list s
//    set the width and x position for all segments
//---------------------------------------------------------

void Measure::computeMinWidth(Segment* s, qreal x, bool isSystemHeader)
{
    Segment* fs = firstEnabled();
    if (!fs->visible()) {           // first enabled could be a clef change on invisible staff
        fs = fs->nextActive();
    }
    bool first  = isFirstInSystem();
    const Shape ls(first ? QRectF(0.0, -1000000.0, 0.0, 2000000.0) : QRectF(0.0, 0.0, 0.0, spatium() * 4));

    if (isMMRest()) {
        // Reset MM rest to initial size and position
        Segment* seg = findSegmentR(SegmentType::ChordRest, Fraction(0,1));
        const int nstaves = score()->nstaves();
        for (int st = 0; st < nstaves; ++st) {
            Rest* mmRest = toRest(seg->element(staff2track(st)));
            if (mmRest) {
                mmRest->rxpos() = 0;
                mmRest->layoutMMRest(score()->styleP(Sid::minMMRestWidth) * mag());
                mmRest->segment()->createShapes();
            }
        }
    }

    while (s) {
        s->rxpos() = x;
        if (!s->enabled() || !s->visible()) {
            s->setWidth(0);
            s = s->next();
            continue;
        }
        Segment* ns = s->nextActive();
        // end barline might be disabled
        // but still consider it for spacing of previous segment
        if (!ns) {
            ns = s->next(SegmentType::BarLineType);
        }
        qreal w;

        if (ns) {
            if (isSystemHeader && (ns->isChordRestType() || (ns->isClefType() && !ns->header()))) {
                // this is the system header gap
                w = s->minHorizontalDistance(ns, true);
                isSystemHeader = false;
            } else {
                w = s->minHorizontalDistance(ns, false);
            }
// printf("  min %f <%s>(%d) <%s>(%d)\n", s->x(), s->subTypeName(), s->enabled(), ns->subTypeName(), ns->enabled());
#if 1
            // look back for collisions with previous segments
            // this is time consuming (ca. +5%) and probably requires more optimization

            if (s == fs) {     // don't let the second segment cross measure start (not covered by the loop below)
                w = std::max(w, ns->minLeft(ls) - s->x());
            }

            int n = 1;
            for (Segment* ps = s; ps != fs;) {
                qreal ww;
                ps = ps->prevActive();

                Q_ASSERT(ps);         // ps should never be nullptr but better be safe.
                if (!ps) {
                    break;
                }

                if (ps->isChordRestType()) {
                    ++n;
                }
                ww = ps->minHorizontalCollidingDistance(ns) - (s->x() - ps->x());

                if (ps == fs) {
                    ww = std::max(ww, ns->minLeft(ls) - s->x());
                }

                if (ww > w) {
                    // overlap !
                    // distribute extra space between segments ps - ss;
                    // only ChordRest segments get more space
                    // TODO: is there a special case n == 0 ?

                    qreal d = (ww - w) / n;
                    qreal xx = ps->x();
                    for (Segment* ss = ps; ss != s;) {
                        Segment* ns1 = ss->nextActive();
                        qreal ww1    = ss->width();
                        if (ss->isChordRestType()) {
                            ww1 += d;
                            ss->setWidth(ww1);
                        }
                        xx += ww1;
                        ns1->rxpos() = xx;
                        ss = ns1;
                    }
                    w += d;
                    x = xx;
                    break;
                }
            }
#endif
        } else {
            w = s->minRight();
        }
        s->setWidth(w);
        x += w;
        s = s->next();
    }
    setStretchedWidth(x);
}

void Measure::computeMinWidth()
{
    Segment* s;

    //
    // skip disabled segment
    //
    for (s = first(); s && !s->enabled(); s = s->next()) {
        s->rxpos() = 0;
        s->setWidth(0);
    }
    if (!s) {
        setWidth(0.0);
        return;
    }
    qreal x;
    bool first = isFirstInSystem();

    // left barriere:
    //    Make sure no elements crosses the left boarder if first measure in a system.
    //
    Shape ls(first ? QRectF(0.0, -1000000.0, 0.0, 2000000.0) : QRectF(0.0, 0.0, 0.0, spatium() * 4));

    x = s->minLeft(ls);

    if (s->isStartRepeatBarLineType()) {
        System* sys = system();
        MeasureBase* pmb = prev();
        if (pmb->isMeasure() && pmb->system() == sys && pmb->repeatEnd()) {
            Segment* seg = toMeasure(pmb)->last();
            // overlap end repeat barline with start repeat barline
            if (seg->isEndBarLineType()) {
                x -= score()->styleP(Sid::endBarWidth) * mag();
            }
        }
    }

    if (s->isChordRestType()) {
        x += score()->styleP(hasAccidental(s) ? Sid::barAccidentalDistance : Sid::barNoteDistance);
    } else if (s->isClefType() || s->isHeaderClefType()) {
        x += score()->styleP(Sid::clefLeftMargin);
    } else if (s->isKeySigType()) {
        x = qMax(x, score()->styleP(Sid::keysigLeftMargin));
    } else if (s->isTimeSigType()) {
        x = qMax(x, score()->styleP(Sid::timesigLeftMargin));
    }
    x += s->extraLeadingSpace().val() * spatium();
    bool isSystemHeader = s->header();

    computeMinWidth(s, x, isSystemHeader);
}
}