@ustk Thank you very much for your reply)
I'll take that into consideration. ❤️

@It_Used Also, KeySpacing and ShowOctaveMark can be const var

And this:

var is_center = (OctCenter == obj.noteNumber); var bg_color = is_center ? Colours.withAlpha(0xB26776, 100) : Colours.withAlpha(0x575757, 100);

can be

var bg_color = Colours.withAlpha((OctCenter == obj.noteNumber) ? 0xB26776 : 0x575757, 100);

or directly

g.setColour(Colours.withAlpha((OctCenter == obj.noteNumber) ? 0xB26776 : 0x575757, 100));

@d-healey Thank you, I will study it and maybe make some changes, or I will use it as a reference.