File Coverage

blib/lib/Music/Tension.pm

Criterion	Covered	Total	%
statement	28	28	100.0
branch	5	8	62.5
condition	2	6	33.3
subroutine	8	8	100.0
pod	3	3	100.0
total	46	53	86.7

# -*- Perl -*-
#
# Parent class for music tension analysis modules.

package Music::Tension;

use 5.010000;
use strict;
use warnings;

use Carp qw/croak/;
use Scalar::Util qw/looks_like_number/;

our $VERSION = '0.70';

########################################################################
#
# SUBROUTINES

sub new {
  my ( $class, %param ) = @_;
  my $self = {};

  # just MIDI support here, see Music::Scala for scala scale file support
  if ( exists $param{reference_frequency} ) {
    croak "reference_frequency must be a number"
      if !looks_like_number $param{reference_frequency};
    $self->{_reference_frequency} = $param{reference_frequency};
  } else {
    $self->{_reference_frequency} = 440;
  }

  bless $self, $class;
  return $self;
}

sub freq2pitch {
  my ( $self, $freq ) = @_;
  croak "frequency must be a positive number"
    if !looks_like_number $freq
    or $freq < 0;

  return sprintf "%.0f",
    69 + 12 * ( log( $freq / $self->{_reference_frequency} ) / log(2) );
}

sub pitch2freq {
  my ( $self, $pitch ) = @_;
  croak "pitch must be MIDI number"
    if !looks_like_number $pitch
    or $pitch < 0;

  return $self->{_reference_frequency} * ( 2**( ( $pitch - 69 ) / 12 ) );
}

1;
__END__