make_motif.m

function motif = make_motif( tile, group )
% motif = make_wallpaper( tile, group )
%   Creates a 2D image wallpaper motif given an m x n image patch
%   and a specified wallpaper group type.
%
%   tile    : m x n sparse matrix
%
%   motif   : sparse matrix
%
%   Written by Rick Gilmore, thatrickgilmore@gmail.com
%
%   Released under GPLv3

%--------------------------------------------------------------------------
%
%   History
%
%   2013-04-21 rog wrote

%--------------------------------------------------------------------------
%
%   Development notes
%
%   2013-04-21  Need to add and test code for complete set of 17 Wallpaper
%               groups.


%   Input parameter checking
if ~ischar( group )
    error('Group must be a string.');
end

%   Test tile


% For each group, transform tile, then assemble motif from transformed
% components

switch group
    case {'p1', 'P1'}
        motif = tile;
    
    case {'p2', 'P2'} % Add Conway terms
        r180 = transform_tile( tile, 'rotate-180');
        
        motif = [ tile r180 ];
    
    case {'pm', 'PM'}
        mh = transform_tile( tile, 'mirror-h');
    
        motif = [ mh;
                  tile ];
    
    case {'pg', 'PG'}
        mv = transform_tile( tile, 'mirror-v');
    
        motif = [ tile;
                  mv ];
    
    case {'cm', 'CM'}
        mv = transform_tile( tile, 'mirror-v');
    
        motif = [ tile mv   tile  mv;
                  mv   tile mv    tile ];
    
    case { 'pmm', 'PMM' }
        mv = transform_tile( tile, 'mirror-v');
        mh = transform_tile( tile, 'mirror-v');
        mb = transform_tile( tile, 'mirror-hv');
        
        motif = [ tile mv;
                  mh   mb ];
              
    case { 'pmg', 'PMG' }
        mv = transform_tile( tile, 'mirror-v');
        mh = transform_tile( tile, 'mirror-v');
        mb = transform_tile( tile, 'mirror-hv');
       
        motif = [ mb tile;
                  mv mh ];
    
    case { 'p4', 'P4' }
        r270 = transform_tile( tile, 'rotate-270' );
        r180 = transform_tile( tile, 'rotate-180' );
        r90  = transform_tile( tile, 'rotate-90' );
        
        motif = [ tile r270;
                  r90  r180 ];
              
    case { 'p4m', 'P4M' }
        r270 = transform_tile( tile, 'rotate-270' );
        r180 = transform_tile( tile, 'rotate-180' );
        r90  = transform_tile( tile, 'rotate-90' );
        
        motif = [ tile r270;
                  r90  r180 ];         
              
    otherwise
        error('Wallpaper group value not supported.');
end

return