/// <summary>
/// Initialize key from a string.
/// </summary>
/// <param name="keyString">Format should be like
/// "C: QC QD QE QF | QD QE QF QG" for C major
/// "Ebm: QEb QF QGb QF | QEb QF QGb QAb" for Eb minor</param>
public Key(string keyString)
{
Match m = Regex.Match(keyString, @"([A-G])([b#])?(m)?");
char name = m.Groups[1].Value[0];
Accidental accidental = Accidental.Natural;
if (m.Groups[2].Value != "")
{
if (m.Groups[2].Value == "b")
{
accidental = Accidental.Flat;
}
else
{
accidental = Accidental.Sharp;
}
}
Pitch p = new Pitch(name, 4, accidental);
if (m.Groups[3].Value == "m")
{
mode = KeyMode.Minor;
}
else
{
mode = KeyMode.Major;
}
string keyName = p.ToString(); // TODO: all the parsing of accidental above, etc isn't necessary if we just use the string anyway.
switch (keyName)
{
#region Silly Case Statements to set "fifths"
case "C":
fifths = 0;
break;
case "G":
fifths = 1;
break;
case "D":
fifths = 2;
break;
case "A":
fifths = 3;
break;
case "E":
fifths = 4;
break;
case "B":
fifths = 5;
break;
case "F#":
fifths = 6;
break;
case "C#":
fifths = 7;
break;
case "G#":
fifths = 8;
break;
case "D#":
fifths = 9;
break;
case "A#":
fifths = 10;
break;
case "E#":
fifths = 11;
break;
case "B#":
fifths = 12;
break;
case "F":
fifths = -1;
break;
case "Bb":
fifths = -2;
break;
case "Eb":
fifths = -3;
break;
case "Ab":
fifths = -4;
break;
case "Db":
fifths = -5;
break;
case "Gb":
fifths = -6;
break;
case "Cb":
fifths = -7;
break;
case "Fb":
fifths = -8;
break;
default:
throw new ArgumentException("Unknown Key: " + keyName);
#endregion
}
}
public override string ToString()
{
Pitch p = new Pitch(cOffset, accidental);
return(p.ToString());
}
/// <summary>
/// Returns an example Pitch in the given key on the given scale degree, in the given octave.
/// </summary>
/// <param name="degree">The scale degree to create.</param>
/// <param name="octave">The c-based octave in which to create the Pitch instance.</param>
/// <returns>The example pitch on the requested scale degree.</returns>
public Pitch GetScaleDegreePitch(ScaleDegree degree, int octave)
{
int numFifths;
bool progressUp;
PitchInterval fifth;
PitchInterval degreeInterval;
numFifths = Math.Abs(Fifths);
progressUp = (Fifths > 0);
fifth = new PitchInterval(7);
// First, find the tonic of the key.
// Start on middle C and loop through the circle of fifths.
Pitch tonic = new Pitch(35, Accidental.Natural);
for (int i = 0; i < numFifths; i++)
{
if (progressUp)
{
tonic += fifth;
tonic.FlipEnharmonic(true, true); // The first argument is true because B# and E# are not allowed.
}
else
{
tonic -= fifth;
tonic.FlipEnharmonic(i < 6, false); // The first argument is used because Cb is allowed (fifths = -7; i=6);
}
}
// Second, add the scale degree to the tonic note.
// Convert the scale degree to a pitch interval.
degreeInterval = new PitchInterval();
switch ((degree.Number - 1) % 7)
{
case 0:
degreeInterval.Interval = 0;
break;
case 1:
degreeInterval.Interval = 2;
break;
case 2:
degreeInterval.Interval = 4;
break;
case 3:
degreeInterval.Interval = 5;
break;
case 4:
degreeInterval.Interval = 7;
break;
case 5:
degreeInterval.Interval = 9;
break;
case 6:
degreeInterval.Interval = 11;
break;
}
// Add back in the # octaves.
degreeInterval += new PitchInterval(12 * ((degree.Number - 1) / 7));
Pitch result = tonic + degreeInterval;
// Pick the correct enharmonic version (assuming no alterations). We use sharps if we are going up on the circle of fifths.
// Natural notes like B are used instead of Cb until we have 6 accidentals. This is a special mixed case where we need to
// use one normal "white key" and one sharp "white key": both B natural and E# are in the key signature in F# major. Similarly,
// in Gb major both Cb and F natural are in the key signature.
// Once we have 7 accidentals, we don't use any natural white keys.
if (numFifths < 6)
{
result.FlipEnharmonic(true, progressUp);
}
else if (numFifths > 6)
{
result.FlipEnharmonic(false, progressUp);
}
else if (fifths == 6) // F# Major.
{
if (degree.Number == 4) // B natural special case.
{
result.FlipEnharmonic(true, true);
}
else
{
result.FlipEnharmonic(false, true);
}
}
else // Gb Major.
{
if (degree.Number == 7) // F natural special case.
{
result.FlipEnharmonic(true, false);
}
else
{
result.FlipEnharmonic(false, false);
}
}
// Set the alteration (this function picks the right enharmonic version if the pitch is already set right for the no alteration case.)
result.ApplyAlteration(degree.Alteration);
// Finally, set the octave.
result.Octave = octave;
return(result);
}
