VocalEasel/mma/MMA/notelen.py

# notelen.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 gbl
from   MMA.common import *


noteLenTable = {
    '0'     : 1,                   # special 0==1 midi tick
    '1'     : gbl.BperQ * 4,       # whole note
    '2'     : gbl.BperQ * 2,       # 1/2
    '23' : gbl.BperQ * 4 / 3,   # 1/2 triplet
    '4'     : gbl.BperQ,           # 1/4
    '43' : gbl.BperQ * 2 / 3,   # 1/4 triplet
    '8'     : gbl.BperQ / 2,       # 1/8
    '81' : None,                # short 1/8 swing note
    '82' : None,                # long 1/8 swing note
    '16' : gbl.BperQ / 4,       # 1/16
    '32' : gbl.BperQ / 8,       # 1/32
    '64' : gbl.BperQ / 16,      # 1/64
    '6'     : gbl.BperQ / 6,       # 1/16 note triplet
    '3'     : gbl.BperQ / 3,       # 1/8 note triplet
    '5'     : gbl.BperQ / 5 }      # 1/8 note quintuplet


def swingMode(ln):
    """ Enable/Disable Swing timing mode. """


    emsg = "Use: SwingMode [ On, Off, 0, 1 Skew=xx ]."

    if not ln:
        error(emsg)


    for v in ln:

        a = v.upper()

        if a in ("ON", "1"):
            gbl.swingMode = 1
            continue

        if a in ("OFF", "0"):
            gbl.swingMode = 0
            continue

        if a.find('=')>1:
            a,b = a.split('=')

            if a == 'SKEW':
                gbl.swingSkew = b
                v = int( stoi(b) * gbl.BperQ / 100)
                noteLenTable['81'] = v
                noteLenTable['82'] = gbl.BperQ - v
                continue

        error(emsg)

    if gbl.debug:
        print "SwingMode: Status=%s, Skew Note lengths: %s and %s ticks." % \
              (gbl.swingMode, noteLenTable['81'], noteLenTable['82'])


swingMode(['Skew=66'])    # Set the default swingskew values.



def getNoteLen(n):
    """ Convert a Note to a midi tick length.

    Notes are 1==Whole, 4==Quarter, etc.
    Notes can be dotted or double dotted.
    Notes can be combined: 1+4 == 5 beats, 4. or 4+8 == dotted 1/4
                           1-4 == 3 beats, 1-0 == 4 beats less a midi tick
    """

    length = 0

    n=n.replace('-', '+-')    # change "2-4" to "2+-4" for easier parsing
    n=n.replace('++-', '+-')  # and in case we already used "+-", take out 2nd "+"

    for a in str(n).split('+'):
        if a.endswith('..'):
            dot = 2
            a=a[:-2]
        elif a.endswith('.'):
            dot = 1
            a=a[:-1]
        else:
            dot = 0

        try:
            if a.startswith('-'):
                i = noteLenTable[a[1:]] * -1
            else:
                i = noteLenTable[a]

        except:
            error("Unknown note duration %s" % n )

        if dot == 2:
            i += i/2 + i/4
        elif dot == 1:
            i += i/2
        length += i

    return length