matthiasm@8: function image_rgb(M)
matthiasm@8: % Show a matrix of integers as a color image.
matthiasm@8: % This is like imagesc, except we know what the mapping is from integer to color.
matthiasm@8: % If entries of M contain integers in {1,2,3}, we map
matthiasm@8: % this to red/green/blue 
matthiasm@8: 
matthiasm@8: cmap = [1 0 0; % red
matthiasm@8: 	0 1 0; % green
matthiasm@8: 	0 0 1; % blue
matthiasm@8: 	127/255 1 212/255]; % aquamarine
matthiasm@8: image(M)
matthiasm@8: set(gcf,'colormap', cmap);
matthiasm@8: 
matthiasm@8: if 1
matthiasm@8:   % make dummy handles, one per object type, for the legend
matthiasm@8:   str = {};
matthiasm@8:   for i=1:size(cmap,1)
matthiasm@8:     dummy_handle(i) = line([0 0.1], [0 0.1]);
matthiasm@8:     set(dummy_handle(i), 'color', cmap(i,:));
matthiasm@8:     set(dummy_handle(i), 'linewidth', 2);
matthiasm@8:     str{i} = num2str(i);
matthiasm@8:   end
matthiasm@8:   legend(dummy_handle, str, -1);
matthiasm@8: end
matthiasm@8: 
matthiasm@8: if 0
matthiasm@8: [nrows ncols] = size(M);
matthiasm@8: img = zeros(nrows, ncols, 3);
matthiasm@8: for r=1:nrows
matthiasm@8:   for c=1:ncols
matthiasm@8:     q = M(r,c);
matthiasm@8:     img(r,c,q) = 1;
matthiasm@8:   end
matthiasm@8: end
matthiasm@8: image(img)
matthiasm@8: end