[MU3 Backend] ENG-58: Fix rare melisma issues #8461

iveshenry18 · 2021-06-30T01:38:21Z

Resolves: ENG-58: Double-check melisma lines (that end on rests and are on additional lyric lines)

These commits fix a couple of subtle issues with melisma lines:

Melismas that end on a different voice than they begin are not correctly terminated in MusicXML import.
Melismas (including hyphens) under rests have incorrect y-positioning.

The first was a matter of loosening the criteria under which an extended lyric is terminated; my change removes a check that the lyric's parent is in the same track as the new (terminating) lyric's. I believe this check was originally in place under the assumption that lyric number corresponds to voice number, but this is not specified in the MusicXML spec, nor really enforced in MuseScore. It also adds the ability to export lyrics under rests (again rare, but technically supported by MusicXML).

The second was a subtle omission of a lyric's ChordRest's y-positioning when calculating the positioning of a melisma or hyphen. This omission is inconsequential on normal lyrics under Chords, since Chords usually (always?) have a y-position of 0 relative to their System. However, with lyrics under Rests (which is an uncommon case, to be sure), this caused an incorrect placement.

I signed CLA
I made sure the code in the PR follows the coding rules
I made sure the code compiles on my machine
I made sure there are no unnecessary changes in the code
I made sure the title of the PR reflects the core meaning of the issue you are solving
I made sure the commit message(s) contain a description and answer the question "Why do those changes fix that particular issue?" or "Why are those changes really necessary as improvements?"
I made sure the commit message title starts with "fix #424242:" if there is a related issue
I created the test (mtest, vtest, script test) to verify the changes I made

This commit fixes a relatively rare bug in importing lyrics. Namely, when a melisma ended on a lyric connected to a note (much less a rest) on a different voice, the melisma would not be properly ended and extend until the next opportunity. This changes the conditions by which a melisma is ended to correct this. This commit also exports lyrics connected to rests, which previously were omitted (but sometimes occur, particularly when the lyrics in a repeat are a different rhythm than the first time).

This commit fixes a very subtle error in the y-positioning of melisma lines on lyrics under rests (a rare situation as-is). In short, the equation for the y-position was ignoring the y-position and y-offset of the lyric's chordrest. In normal circumstances (when a lyric is under a chord), this value is 0, so the bug doesn't present itself until one attempts to put melismas under rests (which is hard to do in the first place, but does occur in some XML imports).

This fixes another track-related oversight in importing melisma lines that caused some (particularly those ending on rests) to be occasionally omitted.

This commit fixes a relatively rare bug in importing lyrics. Namely, when a melisma ended on a lyric connected to a note (much less a rest) on a different voice, the melisma would not be properly ended and extend until the next opportunity. This changes the conditions by which a melisma is ended to correct this. This commit also exports lyrics connected to rests, which previously were omitted (but sometimes occur, particularly when the lyrics in a repeat are a different rhythm than the first time). Duplicate of musescore#8461, part 1

This commit fixes a very subtle error in the y-positioning of melisma lines on lyrics under rests (a rare situation as-is). In short, the equation for the y-position was ignoring the y-position and y-offset of the lyric's chordrest. In normal circumstances (when a lyric is under a chord), this value is 0, so the bug doesn't present itself until one attempts to put melismas under rests (which is hard to do in the first place, but does occur in some XML imports). Duplicate of musescore#8461, part 2

This fixes another track-related oversight in importing melisma lines that caused some (particularly those ending on rests) to be occasionally omitted. Duplicate of musescore#8461, part 3