matthiasm@8: function rootspelling = chordroot_spelling(key, root, degrees)
matthiasm@8: 
matthiasm@8: temp = strsplit(':', key);
matthiasm@8: keyroot = temp{1};
matthiasm@8: if length(temp) > 1
matthiasm@8:     keymode = temp{2};
matthiasm@8: else
matthiasm@8:     keymode = 'major';
matthiasm@8: end
matthiasm@8: 
matthiasm@8: 
matthiasm@8: 
matthiasm@8: % major scale
matthiasm@8: scale{1} = [0 2 4 5 7 9 11];
matthiasm@8: % harmonic minor scale
matthiasm@8: scale{2} = [0 2 3 5 7 8 11];
matthiasm@8: 
matthiasm@8: diatonic = {'C','D','E','F','G','A','B'};
matthiasm@8: keymode_number = find(strcmp({'major','minor'},keymode));
matthiasm@8: 
matthiasm@8: if ischar(root)
matthiasm@8:     rootdegree = find(strcmp(diatonic,root(1)));
matthiasm@8:     rootpc = scale{1}(strcmp(diatonic,root(1))) + length(strfind(root,'#')) - length(strfind(root,'b'));
matthiasm@8: else
matthiasm@8:     [rootdegree, rootdegree]= min(abs(scale{1}-root));
matthiasm@8:     rootpc = root;
matthiasm@8: end
matthiasm@8: 
matthiasm@8: 
matthiasm@8: deg = [];
matthiasm@8: pcs = [];
matthiasm@8: for ii = 1:length(degrees)
matthiasm@8:     deg = [deg mod(rootdegree + str2num(degrees{ii}(end)) - 2,7)+1];
matthiasm@8:     pcs = [pcs mod(rootpc + degree2semitone(degrees{ii}),12)];
matthiasm@8: end
matthiasm@8: 
matthiasm@8: keyrootpc = scale{1}(strcmp(diatonic,keyroot(1))) + length(strfind(keyroot,'#')) - length(strfind(keyroot,'b'));
matthiasm@8: keydegree = find(strcmp(diatonic,keyroot(1)));
matthiasm@8: 
matthiasm@8: scalesemitone = circshift(mod(scale{keymode_number} + keyrootpc,12),[0 keydegree-1]);
matthiasm@8: 
matthiasm@8: fit = [0 0 0];
matthiasm@8: 
matthiasm@8: for deviation = -1:1 % test if the best degree is lower, just right or higher
matthiasm@8:     currdeg = mod(deg+deviation-1,7) + 1;
matthiasm@8:     chordaccidentals = mod(scalesemitone(currdeg) - pcs + 12 + 6,12) - 6;
matthiasm@8:     fit(deviation+2) = sum(abs(chordaccidentals));
matthiasm@8: end
matthiasm@8: [bestfitval, bestfit] = min(fit);
matthiasm@8: bestrootdegree = mod(rootdegree + bestfit - 2 - 1,7) + 1;
matthiasm@8: bestrootaccidentals = mod(rootpc - scale{1}(bestrootdegree)+6,12)-6;
matthiasm@8: switch bestrootaccidentals
matthiasm@8:     case -2 
matthiasm@8:         suff = 'bb';
matthiasm@8:     case -1
matthiasm@8:         suff = 'b';
matthiasm@8:     case 0
matthiasm@8:         suff = '';
matthiasm@8:     case 2 
matthiasm@8:         suff = '##';
matthiasm@8:     case 1
matthiasm@8:         suff = '#';
matthiasm@8: end
matthiasm@8: rootspelling = [diatonic{bestrootdegree}, suff];