/// <summary>
/// Builds a scale.
/// </summary>
/// <param name="tonic">The tonic.</param>
/// <param name="pattern">The scale pattern.</param>
/// <param name="positionInOctaveToSequenceIndex">
/// Must have 12 elements, and is filled with
/// the 0-indexed scale position (or -1) for each position in the octave.
/// </param>
/// <param name="noteSequence">
/// Must have pattern.Ascent.Length elements, and is filled with
/// the notes for each scale degree.
/// </param>
/// <param name="numAccidentals">
/// Filled with the total number of accidentals in the built
/// scale.
/// </param>
private static void Build(Note tonic, ScalePattern pattern,
int[] positionInOctaveToSequenceIndex, Note[] noteSequence, out int numAccidentals)
{
numAccidentals = 0;
for (var i = 0; i < 12; ++i)
{
positionInOctaveToSequenceIndex[i] = -1;
}
var tonicPitch = tonic.PitchInOctave(0);
for (var i = 0; i < pattern.Ascent.Length; ++i)
{
var pitch = tonicPitch + pattern.Ascent[i];
Note note;
if (pattern.Ascent.Length == 7)
{
var letter = (char)(i + tonic.Letter);
if (letter > 'G')
{
letter = (char)(letter - 7);
}
note = pitch.NoteWithLetter(letter);
}
else
{
note = pitch.NotePreferringSharps();
}
noteSequence[i] = note;
positionInOctaveToSequenceIndex[pitch.PositionInOctave()] = i;
}
}
private readonly int[] _positionInOctaveToSequenceIndex; // for each PositionInOctave, the 0-indexed
/// <summary>
/// Constructs a scale from its tonic and its pattern.
/// </summary>
/// <param name="tonic">The tonic note.</param>
/// <param name="pattern">The scale pattern.</param>
/// <exception cref="ArgumentNullException">tonic or pattern is null.</exception>
public Scale(Note tonic, ScalePattern pattern)
{
if (tonic == null || pattern == null)
{
throw new ArgumentNullException();
}
Tonic = tonic;
Pattern = pattern;
_positionInOctaveToSequenceIndex = new int[12];
NoteSequence = new Note[pattern.Ascent.Length];
int numAccidentals;
Build(Tonic, Pattern, _positionInOctaveToSequenceIndex, NoteSequence,
out numAccidentals);
}
protected bool Equals(ScalePattern other)
{
return(string.Equals(Name, other.Name) &&
Ascent.SequenceEqual(other.Ascent));
}
