@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));