Restore historical TAB duration grids without losing rhythm symbols

src/engraving/dom/chordrest.cpp

@@ -683,7 +683,10 @@ void ChordRest::undoChangeProperty(Pid id, const PropertyValue& newValue, Proper
 {
     if (id == Pid::BEAM_MODE) {
         if (isChord() && m_durationType.hooks() == 0) {
-            return;
+            const StaffType* tab = staffType();
+            if (!tab || !tab->isTabStaff() || !tab->genDurations()) {
+                return;
+            }
         }
         BeamMode newBeamMode = newValue.value<BeamMode>();
         if ((newBeamMode == BeamMode::BEGIN16 && m_durationType.hooks() < 2)

src/engraving/rendering/score/chordlayout.cpp

@@ -3461,6 +3461,10 @@ void ChordLayout::fillShape(const Chord* item, ChordRest::LayoutData* ldata)
         shape.add(note->shape().translate(note->pos()));
     }
 
+    if (item->tabDur() && item->tabDur()->addToSkyline()) {
+        shape.add(item->tabDur()->shape().translate(item->tabDur()->pos()));
+    }
+
     for (const NoteParenthesisInfo* parenInfo : item->noteParentheses()) {
         Parenthesis* leftParen = parenInfo->leftParen();
         Parenthesis* rightParen = parenInfo->rightParen();

src/engraving/rendering/score/systemlayout.cpp

@@ -1259,6 +1259,10 @@ void SystemLayout::layoutSystemElements(System* system, LayoutContext& ctx)
         GraceNotesGroup& graceAfter = chord->graceNotesAfter();
         TLayout::layoutGraceNotesGroup2(&graceBefore, graceBefore.mutldata());
         TLayout::layoutGraceNotesGroup2(&graceAfter, graceAfter.mutldata());
+        if (TabDurationSymbol* symbol = chord->tabDur()) {
+            TLayout::layoutTabDurationSymbol2(symbol, symbol->mutldata());
+            ChordLayout::fillShape(chord, chord->mutldata());
+        }
     }
 
     for (ChordRest* cr : elementsToLayout.chordRests) {

src/engraving/rendering/score/tlayout.cpp

@@ -160,6 +160,7 @@
 #include "dom/factory.h"
 
 #include "editing/editchord.h"
+#include "editing/navigation.h"
 
 #include "accidentalslayout.h"
 #include "arpeggiolayout.h"
@@ -5683,11 +5684,32 @@ void TLayout::layoutTabDurationSymbol(const TabDurationSymbol* item, TabDuration
     double xpos, ypos;           // position coords
 
     ldata->beamGrid = TabBeamGrid::NONE;
+    ldata->beamLength = 0.0;
+    ldata->beamLevel = 0;
     Chord* chord = item->ownershipParent() && item->ownershipParent()->isChord() ? toChord(item->ownershipParent()) : nullptr;
+    // A grid replaces the individual duration signs. Only connect equal, undotted
+    // values; otherwise retain the signs rather than lose their rhythm information.
+    auto connects = [](const ChordRest* left, const ChordRest* right) {
+        if (!left || !right || !left->isChord() || !right->isChord()) {
+            return false;
+        }
+        const bool regularChords = !left->isGrace() && !right->isGrace()
+                                   && !toChord(left)->noStem() && !toChord(right)->noStem();
+        const bool sameContext = left->measure() == right->measure() && left->staffType() == right->staffType()
+                                 && left->tuplet() == right->tuplet();
+        const bool equalUndottedDurations = left->durationType() == right->durationType() && !left->dots() && !right->dots();
+        const bool leftContinues = left->beamMode() == BeamMode::BEGIN || left->beamMode() == BeamMode::MID;
+        const bool rightConnects = right->beamMode() == BeamMode::MID || right->beamMode() == BeamMode::END;
+        return regularChords && sameContext && equalUndottedDurations && leftContinues && rightConnects;
+    };
+    const int beamLevel = chord ? static_cast<int>(chord->durationType().type())
+                          - static_cast<int>(item->tab()->tabDurationFont().zeroBeamLevel) : 0;
+    const bool joinsPrevious = beamLevel > 0 && (chord->beamMode() == BeamMode::MID || chord->beamMode() == BeamMode::END)
+                               && connects(Navigation::prevChordRest(chord), chord);
+    const bool joinsNext = beamLevel > 0 && (chord->beamMode() == BeamMode::BEGIN || chord->beamMode() == BeamMode::MID)
+                           && connects(chord, Navigation::nextChordRest(chord));
 // if no chord (shouldn't happens...) or not a special beam mode, layout regular symbol
-    if (!chord || !chord->isChord()
-        || (chord->beamMode() != BeamMode::BEGIN && chord->beamMode() != BeamMode::MID
-            && chord->beamMode() != BeamMode::END)) {
+    if (beamLevel < 1 || (!joinsPrevious && !joinsNext)) {
         FontMetrics fm(item->tab()->durationFont());
         hbb   = item->tab()->durationBoxH();
         wbb   = fm.width(item->text());
@@ -5710,15 +5732,8 @@ void TLayout::layoutTabDurationSymbol(const TabDurationSymbol* item, TabDuration
         ybb   = -hbb;                                   // bbox top is at top of stem height
         xpos  = 0.75 * spatium;                        // conventional centring of stem on fret marks
         ypos  = item->tab()->durationGridYOffset();      // stem start is at bottom
-        if (chord->beamMode() == BeamMode::BEGIN) {
-            ldata->beamGrid = TabBeamGrid::INITIAL;
-            ldata->beamLength = 0.0;
-        } else if (chord->beamMode() == BeamMode::MID || chord->beamMode() == BeamMode::END) {
-            ldata->beamLevel = (static_cast<int>(chord->durationType().type()) - static_cast<int>(font.zeroBeamLevel));
-            ldata->beamGrid = (ldata->beamLevel < 1 ? TabBeamGrid::INITIAL : TabBeamGrid::MEDIALFINAL);
-            // _beamLength and bbox x and width will be set in layout2(),
-            // once horiz. positions of chords are known
-        }
+        ldata->beamLevel = beamLevel;
+        ldata->beamGrid = joinsPrevious ? TabBeamGrid::MEDIALFINAL : TabBeamGrid::INITIAL;
     }
 // set this' mag from parent chord mag (include staff mag)
     double mag = chord != nullptr ? chord->mag() : 1.0;
@@ -5729,6 +5744,23 @@ void TLayout::layoutTabDurationSymbol(const TabDurationSymbol* item, TabDuration
     ldata->setPos(xpos * mag, ypos * mag);
 }
 
+void TLayout::layoutTabDurationSymbol2(const TabDurationSymbol* item, TabDurationSymbol::LayoutData* ldata)
+{
+    if (ldata->beamGrid != TabBeamGrid::MEDIALFINAL) {
+        return;
+    }
+    const ChordRest* previous = Navigation::prevChordRest(toChord(item->ownershipParent()));
+    if (!previous || !previous->tabDur()) {
+        return;
+    }
+    // Horizontal spacing is now final. Drawing applies the symbol magnification again.
+    const double length = previous->tabDur()->pagePos().x() - item->pagePos().x();
+    ldata->beamLength = length / item->magS();
+    RectF bbox = ldata->bbox();
+    bbox.setLeft(std::min(bbox.left(), length));
+    ldata->setBbox(bbox);
+}
+
 void TLayout::layoutTapping(Tapping* item, Tapping::LayoutData* ldata, LayoutContext& ctx)
 {
     TappingLayout::layoutTapping(item, ldata, ctx);

src/engraving/rendering/score/tlayout.h

@@ -342,6 +342,7 @@ class TLayout
     static void layoutSystemText(const SystemText* item, SystemText::LayoutData* ldata);
 
     static void layoutTabDurationSymbol(const TabDurationSymbol* item, TabDurationSymbol::LayoutData* ldata);
+    static void layoutTabDurationSymbol2(const TabDurationSymbol* item, TabDurationSymbol::LayoutData* ldata);
     static void layoutTapping(Tapping* item, Tapping::LayoutData* ldata, LayoutContext& ctx);
     static void layoutTappingHalfSlur(TappingHalfSlur* item);
     static void layoutTempoText(const TempoText* item, TempoText::LayoutData* ldata);

src/engraving/tests/beam_data/historical-tab-grid.mscx

@@ -0,0 +1,90 @@
+<?xml version='1.0' encoding='utf-8'?>
+<museScore version="5.00">
+  <Score>
+    <Division>480</Division>
+    <Style>
+      <pageWidth>8.27</pageWidth>
+      <pageHeight>11.69</pageHeight>
+      <spatium>1.76389</spatium>
+    </Style>
+    <Part id="1">
+      <Staff>
+        <StaffType group="tablature">
+          <lines>6</lines>
+          <lineDistance>1.5</lineDistance>
+          <stemless>1</stemless>
+          <timesig>0</timesig>
+          <durations>1</durations>
+          <durationFontName>MuseScore Tab Italian</durationFontName>
+          <durationFontSize>15</durationFontSize>
+          <durationFontY>0</durationFontY>
+          <fretUseTextStyle>0</fretUseTextStyle>
+          <fretPresetIdx>0</fretPresetIdx>
+          <fretFontSize>9</fretFontSize>
+          <fretFontY>0</fretFontY>
+          <linesThrough>0</linesThrough>
+          <minimStyle>1</minimStyle>
+          <onLines>1</onLines>
+          <showRests>0</showRests>
+          <stemsDown>1</stemsDown>
+          <stemsThrough>0</stemsThrough>
+          <upsideDown>0</upsideDown>
+          <useNumbers>1</useNumbers>
+          <showBackTied>1</showBackTied>
+          <symbolRepeat>3</symbolRepeat>
+        </StaffType>
+      </Staff>
+      <Instrument id="cavaquinho">
+        <trackName>Renaissance Tenor Lute (6 course)</trackName>
+        <minPitchP>43</minPitchP>
+        <maxPitchP>79</maxPitchP>
+        <minPitchA>43</minPitchA>
+        <maxPitchA>79</maxPitchA>
+        <instrumentId>pluck.guitar</instrumentId>
+        <StringData>
+          <frets>24</frets>
+          <string>43</string>
+          <string>48</string>
+          <string>53</string>
+          <string>57</string>
+          <string>62</string>
+          <string>67</string>
+        </StringData>
+        <Channel>
+          <program value="25" />
+          <synti>Fluid</synti>
+        </Channel>
+      </Instrument>
+    </Part>
+    <Staff id="1">
+      <Measure>
+        <voice>
+          <TimeSig>
+            <sigN>2</sigN>
+            <sigD>4</sigD>
+          </TimeSig>
+          <Chord>
+            <BeamMode>auto</BeamMode>
+            <durationType>quarter</durationType>
+            <Note>
+              <pitch>67</pitch>
+              <tpc>15</tpc>
+              <fret>0</fret>
+              <string>0</string>
+            </Note>
+          </Chord>
+          <Chord>
+            <BeamMode>auto</BeamMode>
+            <durationType>quarter</durationType>
+            <Note>
+              <pitch>69</pitch>
+              <tpc>17</tpc>
+              <fret>2</fret>
+              <string>0</string>
+            </Note>
+          </Chord>
+        </voice>
+      </Measure>
+    </Staff>
+  </Score>
+</museScore>

src/engraving/tests/beam_tests.cpp

@@ -21,6 +21,7 @@
  */
 
 #include <gtest/gtest.h>
+#include <memory>
 
 #include "engraving/dom/beam.h"
 #include "engraving/dom/chord.h"
@@ -30,11 +31,14 @@
 #include "engraving/dom/note.h"
 #include "engraving/dom/tremolotwochord.h"
 
+#include "engraving/editing/editbeam.h"
+#include "engraving/editing/editdata.h"
 #include "engraving/editing/flip.h"
+#include "engraving/editing/navigation.h"
 #include "engraving/editing/transaction/transaction.h"
 
-#include "utils/scorerw.h"
 #include "utils/scorecomp.h"
+#include "utils/scorerw.h"
 
 using namespace mu::engraving;
 
@@ -61,6 +65,73 @@ void Engraving_BeamTests::beam(const char* path)
     delete score;
 }
 
+TEST_F(Engraving_BeamTests, historicalTabGridModes)
+{
+    std::unique_ptr<MasterScore> score(ScoreRW::readScore(BEAM_DATA_DIR + u"historical-tab-grid.mscx"));
+    ASSERT_TRUE(score);
+    ChordRest* first = score->firstMeasure()->firstChordRest(0);
+    ASSERT_TRUE(first);
+    ChordRest* second = Navigation::nextChordRest(first);
+    ASSERT_TRUE(second);
+    ASSERT_EQ(first->durationType().type(), DurationType::V_QUARTER);
+    ASSERT_EQ(second->durationType().type(), DurationType::V_QUARTER);
+
+    auto setMode = [&](ChordRest* cr, BeamMode mode) {
+        score->select(cr, SelectType::SINGLE);
+        score->transactionManager()->transaction(TranslatableString::untranslatable("Engraving beam tests"), [&](Transaction& tx) {
+            EditBeam::setBeamMode(tx, score.get(), mode);
+        });
+    };
+    setMode(first, BeamMode::BEGIN);
+    ASSERT_EQ(first->beamMode(), BeamMode::BEGIN);
+    setMode(second, BeamMode::MID);
+    ASSERT_EQ(second->beamMode(), BeamMode::MID);
+
+    EditData ed;
+    score->undoRedo(true, &ed);
+    EXPECT_EQ(second->beamMode(), BeamMode::AUTO);
+    score->undoRedo(true, &ed);
+    EXPECT_EQ(first->beamMode(), BeamMode::AUTO);
+    score->undoRedo(false, &ed);
+    score->undoRedo(false, &ed);
+    EXPECT_EQ(first->beamMode(), BeamMode::BEGIN);
+    EXPECT_EQ(second->beamMode(), BeamMode::MID);
+
+    ASSERT_TRUE(ScoreRW::saveScore(score.get(), u"historicalTabGridModes.mscx"));
+    std::unique_ptr<MasterScore> reopened(ScoreRW::readScore(u"historicalTabGridModes.mscx", true));
+    ASSERT_TRUE(reopened);
+    ChordRest* restored = Navigation::nextChordRest(reopened->firstMeasure()->firstChordRest(0));
+    ASSERT_TRUE(restored);
+    EXPECT_EQ(restored->beamMode(), BeamMode::MID);
+
+    // These modes subdivide modern beams and still require actual hooks.
+    setMode(second, BeamMode::BEGIN16);
+    EXPECT_EQ(second->beamMode(), BeamMode::MID);
+    setMode(second, BeamMode::BEGIN32);
+    EXPECT_EQ(second->beamMode(), BeamMode::MID);
+
+    score->deselectAll();
+    score->transactionManager()->transaction(TranslatableString::untranslatable("Engraving beam tests"), [&](Transaction& tx) {
+        EditBeam::resetBeamMode(tx, score.get());
+    });
+    EXPECT_EQ(first->beamMode(), BeamMode::AUTO);
+    EXPECT_EQ(second->beamMode(), BeamMode::AUTO);
+    score->undoRedo(true, &ed);
+    EXPECT_EQ(first->beamMode(), BeamMode::BEGIN);
+    EXPECT_EQ(second->beamMode(), BeamMode::MID);
+    score->undoRedo(false, &ed);
+    EXPECT_EQ(first->beamMode(), BeamMode::AUTO);
+    EXPECT_EQ(second->beamMode(), BeamMode::AUTO);
+
+    score.reset(ScoreRW::readScore(u"selectionfilter_data/selectionfilter1.mscx"));
+    ASSERT_TRUE(score);
+    ChordRest* quarter = score->firstMeasure()->firstChordRest(0);
+    ASSERT_TRUE(quarter);
+    ASSERT_EQ(quarter->durationType().type(), DurationType::V_QUARTER);
+    setMode(quarter, BeamMode::BEGIN);
+    EXPECT_EQ(quarter->beamMode(), BeamMode::AUTO);
+}
+
 TEST_F(Engraving_BeamTests, beamA)
 {
     beam("Beam-A.mscx");