/** Given a midi note number, return the accidental (if any)
* that should be used when displaying the note in this key signature.
*
* The current measure is also required. Once we return an
* accidental for a measure, the accidental remains for the
* rest of the measure. So we must update the current keymap
* with any new accidentals that we return. When we move to another
* measure, we reset the keymap back to the key signature.
*/
public Accid GetAccidental(int notenumber, int measure)
{
if (measure != prevmeasure)
{
ResetKeyMap();
prevmeasure = measure;
}
Accid result = keymap[notenumber];
if (result == Accid.Sharp)
{
keymap[notenumber] = Accid.None;
keymap[notenumber - 1] = Accid.Natural;
}
else if (result == Accid.Flat)
{
keymap[notenumber] = Accid.None;
keymap[notenumber + 1] = Accid.Natural;
}
else if (result == Accid.Natural)
{
keymap[notenumber] = Accid.None;
int nextkey = NoteScale.FromNumber(notenumber + 1);
int prevkey = NoteScale.FromNumber(notenumber - 1);
/* If we insert a natural, then either:
* - the next key must go back to sharp,
* - the previous key must go back to flat.
*/
if (notenumber > 0)
{
if (keymap[notenumber - 1] == Accid.None && keymap[notenumber + 1] == Accid.None &&
NoteScale.IsBlackKey(nextkey) && NoteScale.IsBlackKey(prevkey))
{
if (num_flats == 0)
{
keymap[notenumber + 1] = Accid.Sharp;
}
else
{
keymap[notenumber - 1] = Accid.Flat;
}
}
else if (keymap[notenumber - 1] == Accid.None && NoteScale.IsBlackKey(prevkey))
{
keymap[notenumber - 1] = Accid.Flat;
}
else if (keymap[notenumber + 1] == Accid.None && NoteScale.IsBlackKey(nextkey))
{
keymap[notenumber + 1] = Accid.Sharp;
}
else
{
/* Shouldn't get here */
}
}
}
return(result);
}
/** Given a midi note number, return the white note (the
* non-sharp/non-flat note) that should be used when displaying
* this note in this key signature. This should be called
* before calling GetAccidental().
*/
public WhiteNote GetWhiteNote(int notenumber)
{
int notescale = NoteScale.FromNumber(notenumber);
int octave = (notenumber + 3) / 12 - 1;
int letter = 0;
int[] whole_sharps =
{
WhiteNote.A, WhiteNote.A,
WhiteNote.B,
WhiteNote.C, WhiteNote.C,
WhiteNote.D, WhiteNote.D,
WhiteNote.E,
WhiteNote.F, WhiteNote.F,
WhiteNote.G, WhiteNote.G
};
int[] whole_flats =
{
WhiteNote.A,
WhiteNote.B,WhiteNote.B,
WhiteNote.C,
WhiteNote.D,WhiteNote.D,
WhiteNote.E,WhiteNote.E,
WhiteNote.F,
WhiteNote.G,WhiteNote.G,
WhiteNote.A
};
Accid accid = keymap[notenumber];
if (accid == Accid.Flat)
{
letter = whole_flats[notescale];
}
else if (accid == Accid.Sharp)
{
letter = whole_sharps[notescale];
}
else if (accid == Accid.Natural)
{
letter = whole_sharps[notescale];
}
else if (accid == Accid.None)
{
letter = whole_sharps[notescale];
/* If the note number is a sharp/flat, and there's no accidental,
* determine the white note by seeing whether the previous or next note
* is a natural.
*/
if (NoteScale.IsBlackKey(notescale))
{
if (keymap[notenumber - 1] == Accid.Natural &&
keymap[notenumber + 1] == Accid.Natural)
{
if (num_flats > 0)
{
letter = whole_flats[notescale];
}
else
{
letter = whole_sharps[notescale];
}
}
else if (keymap[notenumber - 1] == Accid.Natural)
{
letter = whole_sharps[notescale];
}
else if (keymap[notenumber + 1] == Accid.Natural)
{
letter = whole_flats[notescale];
}
}
}
/* The above algorithm doesn't quite work for G-flat major.
* Handle it here.
*/
if (num_flats == Gflat && notescale == NoteScale.B)
{
letter = WhiteNote.C;
}
if (num_flats == Gflat && notescale == NoteScale.Bflat)
{
letter = WhiteNote.B;
}
if (num_flats > 0 && notescale == NoteScale.Aflat)
{
octave++;
}
return(new WhiteNote(letter, octave));
}