Ledger lines clear stems when voices overlap

[miiizen]

Resolves: #18724

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[cbjeukendrup]

Is there a particular reason to check noStem()? As far as I know, whenever noStem is true, the stem is (supposed to be) removed, based on the value of shouldHaveStem().

[cbjeukendrup]

I see a hard-coded offset here, but the length of ledger lines can be varied using Sid::ledgerLineLength. Shouldn't that be taken into account?

[cbjeukendrup]

What about using firstLedgerBelow here too?

Suggested change

	if (bottomUpNote->line() > staff->lines(bottomUpNote->tick()) * 2 - 1 && topDownNote->line() < bottomUpNote->line()
	if (bottomUpNote->line() > firstLedgerBelow - 1 && topDownNote->line() < bottomUpNote->line()

[miiizen]

That review unearthed quite a few issues, apologies. After a bit of a refactor:

• Moved code to a more correct place so we don't check separation twice
• Hooks are considered properly - 0.15sp created from the edge of the hook glyph to adjacent ledger line, and 0.15sp created when downstem hooks moved to right of upstem note
• Made adjustment 0.15sp from the end of the ledger line, taking into account Sid::ledgerLineLength
• Differently sized noteheads taken into account
• Prevent notehead and ledger line collisions
• Tuck notes with hooks underneath higher notes when hook doesn't collide with notehead
• Updated tests

[cbjeukendrup]

@oktophonie This may need re-testing since there were quite some changes since your approval. But perhaps you already did, I'm not sure.