VocalEasel/mma/MMA/chords.py

# chords.py

"""
This module is an integeral part of the program
MMA - Musical Midi Accompaniment.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

Bob van der Poel <bob@mellowood.ca>

"""

import copy

from MMA.common import *
from MMA.chordtable import chordlist
import MMA.roman

####################################################
# Convert a roman numeral chord to standard notation



def defChord(ln):
    """ Add a new chord type to the chords{} dict. """

    emsg="DefChord needs NAME (NOTES) (SCALE)"

    # At this point ln is a list. The first item should be
    # the new chord type name.

    if not len(ln):
        error(emsg)
    name = ln.pop(0)
    if name in chordlist.keys():
        warning("Redefining chordtype '%s'" % name)

    if '/' in name:
        error("A slash in not permitted in chord type name")

    if '>' in name:
        error("A '>' in not permitted in chord type name")

    ln=pextract(''.join(ln), '(', ')')

    if ln[0] or len(ln[1])!=2:
        error(emsg)

    notes=ln[1][0].split(',')
    if len(notes) < 2 or len(notes)>8:
        error("There must be 2..8 notes in a chord, not '%s'" % len(note))
    notes.sort()
    for i,v in enumerate(notes):
        v=stoi(v, "Note offsets in chord must be integers, not '%s'" % v)
        if v<0 or v>24:
            error("Note offsets in chord must be 0..24, not '%s'" % v)
        notes[i]=v

    scale=ln[1][1].split(',')
    if len(scale) != 7:
        error("There must be 7 offsets in chord scale, not '%s'" % len(scale))
    scale.sort()
    for i,v in enumerate(scale):
        v=stoi(v, "Scale offsets in chord must be integers, not '%s'" % v)
        if v<0 or v>24:
            error("Scale offsets in chord must be 0..24, not '%s'" % v)
        scale[i]=v


    chordlist[name] = ( notes, scale, "User Defined")

    if gbl.debug:
        print "ChordType '%s', %s" % (name, chordlist[name])


def printChord(ln):
    """ Display the note/scale/def for chord(s). """

    for c in ln:
        try:
            print c, ':', chordlist[c][0], chordlist[c][1], chordlist[c][2]
        except:
            error("Chord '%s' is unknown" % c)
        


""" Table of chord adjustment factors. Since the initial chord is based
    on a C scale, we need to shift the chord for different degrees. Note,
    that with C as a midpoint we shift left for G/A/B and right for D/E/F.

    Should the shifts take in account the current key signature?
"""

cdAdjust = {
    'Gb':-6,
    'G' :-5,
    'G#':-4, 'Ab':-4,
    'A' :-3,
    'A#':-2, 'Bb':-2,
    'B' :-1, 'Cb':-1,
    'B#': 0, 'C' : 0,
    'C#': 1, 'Db': 1,
    'D' : 2,
    'D#': 3, 'Eb': 3,
    'E' : 4, 'Fb': 4,
    'E#': 5, 'F' : 5,
    'F#': 6 }

def chordAdjust(ln):
    """ Adjust the chord point up/down one octave. """

    notpair, ln = opt2pair(ln)

    if not ln:
        error("ChordAdjust: Needs at least one argument.")
    if notpair:
         error("ChordAdjust: All args have to be in the format opt=value.")

    for pitch, octave in ln:
        if pitch not in cdAdjust:
            error("ChordAdjust: '%s' is not a valid pitch" % pitch)

        octave = stoi(octave, "ChordAdjust: expecting integer, not '%s'" % octave)

        p=cdAdjust[pitch]
        if octave == 0:
            if p < -6:
                cdAdjust[pitch] += 12
            elif p > 6:
                cdAdjust[pitch]-=12

        elif octave == -1 and p <= 6 and p >= -6:
            cdAdjust[pitch] -= 12

        elif octave == 1 and p <= 6 and p >= -6:
            cdAdjust[pitch] += 12

        else:
            error("ChordAdjust: '%s' is not a valid octave. Use 1, 0 or -1" % octave)



###############################
# Chord creation/manipulation #
###############################

class ChordNotes:
    """ The Chord class creates and manipulates chords for MMA. The
    class is initialized with a call with the chord name. Eg:

    ch = ChordNotes("Am")

    The following methods and variables are defined:

    noteList  - the notes in the chord as a list. The "Am"
        would be [9, 12, 16].

    noteListLen     - length of noteList.

    tonic       - the tonic of the chord ("Am" would be "A").

    chordType  - the type of chord ("Am" would be "m").

    rootNote   - the root note of the chord ("Am" would be a 9).

    bnoteList  - the original chord notes, bypassing any
    invert(), etc. mangling.

    scaleList  - a 7 note list representing a scale similar to
    the chord.

    reset() - resets noteList to the original chord notes.
    This is useful to restore the original after
    chord note mangling by invert(), etc. without having to
    create a new chord object.


    invert(n) - Inverts a chord by 'n'. This is done inplace and
    returns None. 'n' can have any integer value, but -1 and 1
    are most common. The order of the notes is not changed. Eg:

    ch=Chord('Am')
    ch.noteList == [9, 12, 16]
    ch.invert(1)
    ch.noteList     = [21, 12, 16]

    compress() - Compresses the range of a chord to a single octave. This is
    done inplace and return None. Eg:

    ch=Chord("A13")
    ch.noteList == [1, 5, 8, 11, 21]
    ch.compress()
    ch.noteList == [1, 5, 8, 11, 10 ]


    limit(n) -    Limits the range of the chord 'n' notes. Done inplace
    and returns None. Eg:

    ch=Chord("CM711")
    ch.noteList == [0, 4, 7, 11, 15, 18]
    ch.limit(4)
    ch.noteList ==    [0, 4, 7, 11]


    """


    #################
    ### Functions ###
    #################

    def __init__(self, name):
        """ Create a chord object. Pass the chord name as the only arg.

        NOTE: Chord names ARE case-sensitive!

        The chord NAME at this point is something like 'Cm' or 'A#7'.
        Split off the tonic and the type.
        If the 2nd char is '#' or 'b' we have a 2 char tonic,
        otherwise, it's the first char only.

        A chord can start with a single '+' or '-'. This moves
        the entire chord and scale up/down an octave.

        Note pythonic trick: By using ranges like [1:2] we
        avoid runtime errors on too-short strings. If a 1 char
        string,     name[1] is an error; name[1:2] just returns None.

        Further note: I have tried to enable caching of the generated
        chords, but found no speed difference. So, to make life simpler
        I've decided to generate a new object each time.

        """

        slash = None
        wmessage = ''   # slash warning msg, builder needed for gbl.rmShow
        octave = 0
        inversion = 0

        if name == 'z':
            self.tonic = self.chordType = None
            self.noteListLen = 0
            self.notesList = self.bnoteList = []
            return

        if '/' in name and '>' in name:
            error("You cannot use both an inversion and a slash in the same chord")

        if ':' in name:
            name, barre = name.split(':', 1)
            barre = stoi(barre, "Expecting integer after ':'")
            if barre < -20 or barre > 20:
                error("Chord barres limited to -20 to 20 (more is silly)")
        else:
            barre = 0

        if '>' in name:
            name, inversion = name.split('>', 1)
            inversion = stoi(inversion, "Expecting integer after '>'")
            if inversion < -5 or inversion > 5:
                error("Chord inversions limited to -5 to 5 (more seems silly)")

        if name.startswith('-'):
            name = name[1:]
            octave = -12

        if name.startswith('+'):
            name = name[1:]
            octave = 12

        # we have just the name part. Save 'origname' for debug print

        origName = name = name.replace('&', 'b')

        # Strip off the slash part of the chord. Use later
        # to do proper inversion.

        if name.find('/') > 0:
            name, slash = name.split('/')

        if name[0] in ("I", "V", "i", "v"):
            n=name
            name = MMA.roman.convert(name)

        if name[1:2] in ( '#b' ):
            tonic = name[0:2]
            ctype  = name[2:]
        else:
            tonic = name[0:1]
            ctype  = name[1:]

        if not ctype:        # If no type, make it a Major
            ctype='M'

        try:
            notes = chordlist[ctype][0]
            adj =    cdAdjust[tonic] + octave
        except:
            error( "Illegal/Unknown chord name: '%s'" % name )

        self.noteList     = [ x + adj for x in notes ]
        self.bnoteList     = tuple(self.noteList)
        self.scaleList     = tuple([ x + adj for x in chordlist[ctype][1] ])
        self.chordType     = ctype
        self.tonic         = tonic
        self.rootNote     = self.noteList[0]
        self.barre        = barre

        self.noteListLen = len(self.noteList)

        # Inversion

        if inversion:
            self.invert(inversion)
            self.bnoteList = tuple(self.noteList)

        # Do inversions if there is a valid slash notation.

        if slash:   # convert Roman or Arabic to name of note from chord scale
            if slash[0] in ('I', 'i', 'V', 'v') or slash[0].isdigit():
                n = MMA.roman.rvalue(slash)
                n = self.scaleList[n]           # midi value
                while n >=12:
                    n-=12
                while n<0:
                    n+=12

                slash = ('C', 'C#', 'D', 'D#', 'E', 'F',
                         'F#', 'G', 'G#', 'A', 'A#', 'B')[n]
            try:
                r=cdAdjust[slash]    # r = -6 to 6
            except KeyError:
                error("The note '%s' in the slash chord is unknown" % slash)

            # If the slash note is in the chord we invert
            # the chord so the slash note is in root position.

            c_roted = 0
            s=self.noteList
            for octave in [0, 12, 24]:
                if r+octave in s:
                    rot=s.index(r+octave)
                    for i in range(rot):
                        s.append(s.pop(0)+12)
                    if s[0] >= 12:
                        for i,v in enumerate(s):
                            s[i] = v-12
                            self.noteList = s
                    self.bnoteList = tuple(s)
                    self.rootNote = self.noteList[0]
                    c_roted = 1
                    break

            s_roted = 0
            s=list(self.scaleList)
            for octave in [0, 12, 24]:
                if r+octave in s:
                    rot=s.index(r+octave)
                    for i in range(rot):
                        s.append(s.pop(0)+12)
                        if s[0] > 12:
                            for i,v in enumerate(s):
                                s[i] = v-12
                        self.scaleList=tuple(s)
                    s_roted = 1
                    break

            if not c_roted and not s_roted:
                wmessage = "The slash chord note '%s' not in chord or scale" % slash
                if not gbl.rmShow:
                    warning(wmessage)

            elif not c_roted:
                wmessage = "The slash chord note '%s' not in chord '%s'" % (slash, name)
                if not gbl.rmShow:
                    warning(wmessage)

            elif not s_roted:    # Probably will never happen :)
                wmessage = "The slash chord note '%s' not in scale for the chord '%s'" \
                            % (slash, name)
                if not gbl.rmShow:
                    warning(wmessage)

        if gbl.rmShow:
            if slash:
                a = '/'+slash
            else:
                a = ''
            if wmessage:
                a+='   ' + wmessage
            print " %03s] %-09s -> %s%s" % (gbl.lineno, origName, name, a)

    def reset(self):
        """ Restores notes array to original, undoes mangling. """

        self.noteList     = list(self.bnoteList[:])
        self.noteListLen = len(self.noteList)


    def invert(self, n):
        """ Apply an inversion to a chord.

        This does not reorder any notes, which means that the root note of
        the chord reminds in postion 0. We just find that highest/lowest
        notes in the chord and adjust their octave.

        NOTE: Done on the existing list of notes. Returns None.
        """

        if n:
            c=self.noteList[:]

            while n>0:        # Rotate up by adding 12 to lowest note
                n -= 1
                c[c.index(min(c))]+=12

            while n<0:        # Rotate down, subtract 12 from highest note
                n += 1
                c[c.index(max(c))]-=12

            self.noteList = c

        return None



    def compress(self):
        """ Compress a chord to one ocatve.


        Get max permitted value. This is the lowest note
        plus 12. Note: use the unmodifed value bnoteList!
        """

        mx = self.bnoteList[0] + 12
        c=[]

        for i, n in enumerate(self.noteList):
            if n > mx:
                n -= 12
            c.append(n)

        self.noteList = c

        return None



    def limit(self, n):
        """ Limit the number of notes in a chord. """

        if n < self.noteListLen:
            self.noteList =     self.noteList[:n]
            self.noteListLen = len(self.noteList)

        return None


    def center1(self, lastChord):
        """ Descriptive comment needed here!!!! """

        def minDistToLast(x, lastChord):
            dist=99
            for j in range(len(lastChord)):
                if abs(x-lastChord[j])<abs(dist):
                    dist=x-lastChord[j]
            return dist

        def sign(x):
            if (x>0):
                return 1
            elif (x<0):
                return -1
            else:
                return 0

        # Only change what needs to be changed compared to the last chord
        # (leave notes where they are if they are in the new chord as well).

        if lastChord:
            ch=self.noteList

            for i in range(len(ch)):

                # minimize distance to last chord

                oldDist = minDistToLast(ch[i], lastChord)
                while abs(minDistToLast(ch[i] - sign(oldDist)*12,
                                lastChord)) < abs(oldDist):
                    ch[i] -= 12* sign(oldDist)
                    oldDist = minDistToLast(ch[i], lastChord)

        return None

    def center2(self, centerNote, noteRange):
        """ Need COMMENT """

        ch=self.noteList
        for i,v in enumerate(ch):

            dist = v - centerNote
            if dist < -noteRange:
                ch[i] = v + 12 * ( abs(dist) / 12+1 )
            if dist > noteRange:
                ch[i] = v - 12 * ( abs(dist) / 12+1 )


        return None


######## End of Chord class #####