adding note in plugin: sound ok, but not display

thanks @Miwarre and @heuchi, indeed setting tpc1 and tpc2 allows to change the note display.

Now I struggle with the computation of that tpc for new notes. How can I compute the tpc of a note from adding an interval to another note?

My plugin at https://github.com/berteh/musescore-chordsToNotes/ will generate notes from chords notation (Harmony, in MuseScore). It does so by:
- finding the midi pitch and tpc of the harmony root (works)
- adding a note to play that root (works)
- selecting the semitones to add to that note from the Chord name (works)
- adding a note for each of these semitones (note added with the right midi pitch, but not the right tpc).

For a chord CMaj the root is C (pitch 48, tpc 14), and the semitones [4,7].
From my poor understanding of tpc , I want to add a E (pitch 52, tpc 18) and G (pitch 55, tpc 15).

What formula can I use to compute the tpc of these E and G from the infos on C and semitones, that would work for any (valid) value of root tpc and any amount of semitones (max. 21)?

thanks Miwarre. That discussion on figured bass is indeed very interesting, wish I would have spotted it earlier :/

I indeed followed a similar line of thought , converting a pitch offset (in semitones) to a tpc offset.

Nevertheless, as I am interested in handling most common chords notations, I thought I could simplify the interpretation by going in general for the just/augmented interval but for a few that are usually minor/diminished (3, 6, 10).

If I take a table notation as in the post you refer to that would show like:

pitch offset      tpc offset
(from root)      (from root)
0                    0
1                    7
2                    2
3                   -3   (minor third)
4                    4
5                   -1  
6                   -6  (diminished fifth)
7                    1
8                    8
9                    3
10                  -2  (diminished ninth)
11                   5

In javascript/QML that looks like :
{syntaxhighlighter brush:javascript;}
/** returns tpc of note that is #semitone half-tones higher than rootTPC
eg: semitoneToTPC (tpc of C#, 4) = tpc of E# */
function semitoneToTPC(rootTpc, semitone){
var semiToTpcDiff = [0, 7, 2, -3, 4, -1, -6, 1, 8, 3, -2, 5];
return (rootTpc + semiToTpcDiff[semitone%12]);
}
{/syntaxhighlighter}

Result can be seen/heard in the musescore file Chord Chard after Generation . Let me know what you think of it!