diff chordtools/note2interval.m @ 1:8973548174c1 tip

adding tools to repo

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/chordtools/note2interval.m	Mon May 06 14:43:47 2013 +0100
@@ -0,0 +1,136 @@
+%
+%NOTE2INTERVAL convert a note to an interval w.r.t. a given root
+% 
+% [interval,success,errormessage] = note2interval(note,root,{octave},{verbose})
+% 
+% Converts a note string to an interval with respect to a given root note.
+% Optional value octave gives octave offset to account for extended
+% degrees.
+% 
+% Success = 1 if note converted correctly, 0 otherwise.
+% 
+% Optional argument octave defaults to 0.  
+% 
+% If optional argument 'verbose' is 1, function prints any errormessage to 
+% the screen.
+% 
+% calls: note2fifthposition
+%
+% returns:  interval (string)
+%           success (boolean)
+%           errormessage (string)
+% 
+%
+% Author: Christopher Harte,  March 2009
+% 
+% Copyright: Centre for Digital Music, Queen Mary University of London 2005 
+%
+% This file is part of the C4DM Chord Toolkit V2.0  
+%
+% The C4DM Chord Toolkit 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.
+%
+% The C4DM Chord Toolkit 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 the C4DM Toolkit; if not, write to the Free Software
+% Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+%		
+function [interval,success,errormessage] = note2interval(note, root,octave, verbose)
+
+% set verbose default to 0
+if nargin < 3
+   octave = 0; 
+   verbose = 0;
+
+elseif nargin < 4
+   verbose = 0;
+end
+
+errormessage = '';
+success = 1;
+interval = '';
+
+% degree translations on the line of fifths
+fifthtranslations = [1,5,2,6,3,7,4];
+
+
+% get note and root natural position and accidentals on line of fifths 
+[noteposition, success1,error1] = note2fifthposition(note);
+  
+[rootposition, success2,error2] = note2fifthposition(root);
+
+if success1 && success2
+
+    % take the difference between the two note positions for relative positions
+    % of notes with respect to one and other
+    fifthsdifference = noteposition - rootposition + 1;
+
+    % natural difference on line of fifths
+    fifthsdegree = mod((fifthsdifference-1),7);
+
+    i=0;
+
+    % find number of accidentals apart on line of fifths
+    if fifthsdifference < 0 % if above 0 then either natural or sharp
+
+      %if final position is negative then calculate number of flats
+        % remembering to include the extra first flat (-1)
+        accidentals = fix((fifthsdifference+1)/7) -1;
+    
+    else
+        % note is a natural or has a number of sharps
+        accidentals = fix(fifthsdifference/7);
+
+    end
+
+
+    % put the required number of sharps or flats into the output string
+    if accidentals > 0
+        
+        for i=1:accidentals
+            
+           interval = ['#' interval];
+            
+        end
+        
+    elseif accidentals <=0
+        
+        for i=1:abs(accidentals)
+            
+           interval = ['b' interval];
+            
+        end
+    end    
+    
+    
+    % find degree value from translation array
+    degree = fifthtranslations(fifthsdegree+1);
+
+    if octave >= 0
+        degree = degree + 7.*octave;
+    else
+        success = 0;
+        errormessage = 'Error in note2interval: Octave argument is negative';
+    end
+
+
+
+    interval = [interval num2str(degree)];
+
+else
+    success = 0;
+    errormessage = [error1 error2];
+end
+    
+if (success == 0) && (verbose == 1)   
+    fprintf(1,errormessage);
+end  
+
+