Fix chord symbols alignment when multiple staves have chord symbols

[cbjeukendrup]

Resolves: #31927

Follow-up to #29745

Summary by CodeRabbit

• Bug Fixes
  • Improved harmony and fret diagram positioning in sheet music by enhancing duplicate detection to consider both note timing and staff position, resulting in better vertical alignment of these musical elements.

[miiizen]

Thank you! Looks good to me, I've just added a vtest.

[coderabbitai]

📝 Walkthrough

Walkthrough

Updated duplicate-detection logic in harmony and fret diagram layout methods to track both tick position and staff index as a pair, replacing individual tick-only tracking. This enables correct alignment of chord symbols across multiple staves within a system.

Changes

Cohort / File(s)	Summary
Harmony and Fret Diagram Layout src/engraving/rendering/score/systemlayout.cpp	Replaced std::map<Fraction, staff_idx_t> with std::set<std::pair<Fraction, staff_idx_t>> in layoutHarmonies() and layoutFretDiagrams() to track harmony positions by both tick and staff index. Updated membership checks to use (tick, staffIdx) pairs. Adjusted autoplace call to use the correct harmony object reference.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title directly describes the main change: fixing chord symbol alignment across multiple staves in a system.
Description check	✅ Passed	The description includes an issue reference (#31927) and context (follow-up to #29745), but lacks detail about the implementation and test coverage.
Linked Issues check	✅ Passed	The code changes directly address the reported issue (#31927) by fixing how chord symbols are tracked and positioned across multiple staves.
Out of Scope Changes check	✅ Passed	All changes are focused on the systemlayout.cpp file and directly relate to the harmony and fret diagram positioning logic needed to fix chord symbol alignment.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

src/engraving/rendering/score/systemlayout.cpp (1)

1123-1127: ⚠️ Potential issue | 🟠 Major

Fix the incomplete erase-remove idiom in two locations.

Lines 1126 and 1144 use an incomplete form of the erase-remove idiom. The std::remove() call moves matching elements to the end and returns an iterator, but erase() must be called with both the iterator and the container's end to remove the entire moved range. Currently, only one element is erased; if the same Harmony* appears twice, one copy survives and can still participate in alignment logic. This creates silent correctness issues in harmony placement.

Suggested fix

         if (muse::contains(fretHarmonyPositions, { fd->tick(), fd->staffIdx() })) {
             fretOrHarmonyItemsNoAlign.push_back(fd);
             if (fd->harmony()) {
-                harmonyItemsAlign.erase(std::remove(harmonyItemsAlign.begin(), harmonyItemsAlign.end(), fd->harmony()));
+                harmonyItemsAlign.erase(
+                    std::remove(harmonyItemsAlign.begin(), harmonyItemsAlign.end(), fd->harmony()),
+                    harmonyItemsAlign.end());
                 fretOrHarmonyItemsNoAlign.push_back(fd->harmony());
             }
             continue;
@@
         if (muse::contains(fretHarmonyPositions, { h->tick(), h->staffIdx() })) {
-            harmonyItemsAlign.erase(std::remove(harmonyItemsAlign.begin(), harmonyItemsAlign.end(), h));
+            harmonyItemsAlign.erase(
+                std::remove(harmonyItemsAlign.begin(), harmonyItemsAlign.end(), h),
+                harmonyItemsAlign.end());
             fretOrHarmonyItemsNoAlign.push_back(h);
             continue;
         }

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: ASSERTIVE

Plan: Pro

Run ID: 43c984a2-3018-4f38-92d0-dcc5d44ca0bf

📥 Commits

Reviewing files that changed from the base of the PR and between c3842f5 and 5baef5b.

📒 Files selected for processing (2)

• src/engraving/rendering/score/systemlayout.cpp
• vtest/scores/harmony-align-2.mscz