{"id":2869,"date":"2011-06-24T12:51:20","date_gmt":"2011-06-24T12:51:20","guid":{"rendered":"https:\/\/blogs.mathworks.com\/pick\/2011\/06\/24\/flexible-legends\/"},"modified":"2011-06-25T15:47:34","modified_gmt":"2011-06-25T15:47:34","slug":"flexible-legends","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/pick\/2011\/06\/24\/flexible-legends\/","title":{"rendered":"Flexible Legends"},"content":{"rendered":"
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Jiro<\/a>'s pick this week is legendflex<\/tt><\/a> by Kelly Kearney<\/a>.\r\n <\/p>\r\n <\/introduction>\r\n

When I talk to users who are experienced in Handle Graphics<\/a>, I sometimes get asked about customizing legends<\/a>. This could be somewhat tricky, especially since legends are axes objects with various callbacks and listeners built in.\r\n When I ask what exactly they would want to customize, they mention things like adding titles and tiling legends in different\r\n orientations.\r\n <\/p>\r\n

Earlier this year, Brett<\/a> wrote a post<\/a> highlighting columnlegend<\/tt><\/a> which allows you to create legends with multiple columns. Kelly's legendflex<\/tt> takes it one step further and gives you additional flexibility in adding titles and placing multiple legends systematically.\r\n <\/p>\r\n

Take a look at this example where I show solutions to a 2nd order ordinary differential equation with varying parameters.\r\n The line color and style represent different things, and the multiple legends accurately describe that.\r\n <\/p>

% Define parameters<\/span>\r\nm = 5;         % mass<\/span>\r\nb = [0.5 1 2]; % damping<\/span>\r\nk = [0.5 1 2]; % stiffness<\/span>\r\n\r\n% Define colors and styles<\/span>\r\ncolors     = {[1 0 0], [0 .5 0], [0 0 1]};\r\nlinestyles = {'-'<\/span>, '--'<\/span>, ':'<\/span>};\r\n\r\n% Preallocate variable<\/span>\r\nh = nan(length(k), length(b));\r\n\r\n% Simulate for each combination of b and k<\/span>\r\nfor<\/span> kID = 1:length(k)\r\n   for<\/span> bID = 1:length(b)\r\n      [T, Y] = ode45(@(t, y) [y(2); -1\/m*(k(kID)*y(1)+b(bID)*y(2))], ...<\/span>\r\n         [0, 25], ...<\/span>   % simulate for 25 seconds<\/span>\r\n         [1, 0]);       % initial conditions<\/span>\r\n\r\n      % Plot<\/span>\r\n      h(kID, bID) = line(T, Y(:, 1), ...<\/span>\r\n         'LineWidth'<\/span>, 2, ...<\/span>\r\n         'Color'<\/span>    , colors{kID}, ...<\/span>\r\n         'LineStyle'<\/span>, linestyles{bID});\r\n   end<\/span>\r\nend<\/span>\r\n\r\nylim([-1.2 1.2]); box on<\/span>;\r\nxlabel('Time (sec)'<\/span>);\r\nylabel('Displacement (m)'<\/span>);\r\ntitle(sprintf(['5x\\\\prime\\\\prime + b x\\\\prime + k x = 0\\n'<\/span>, ...<\/span>\r\n   'x = 1, x\\\\prime = 0'<\/span>]));\r\n\r\n% Create a legend for Damping and place it flush against the corner<\/span>\r\n[h1, o_h] = legendflex(h(1, :), cellstr(num2str(b')), ...<\/span>\r\n   'ref'<\/span>, gca, 'anchor'<\/span>, {'ne'<\/span>, 'ne'<\/span>}, 'buffer'<\/span>, [0 0], ...<\/span>\r\n   'title'<\/span>, {'Line Style'<\/span>, 'Damping (N-s\/m)'<\/span>});\r\n% Set the color of lines to black<\/span>\r\nset(o_h, 'Color'<\/span>, 'black'<\/span>);\r\n\r\n% Create a legend for Stiffness and place it 10 pixels left of<\/span>\r\n%        the Damping legend<\/span>\r\nlegendflex(h(:, 1), cellstr(num2str(k')), ...<\/span>\r\n   'ref'<\/span>, h1, 'anchor'<\/span>, {'nw'<\/span>, 'ne'<\/span>}, 'buffer'<\/span>, [-10 0], ...<\/span>\r\n   'title'<\/span>, {'Color'<\/span>, 'Stiffness (N\/m)'<\/span>});<\/pre> 
Comments<\/b><\/p>\r\n   
Give it a try and let us know what you think here<\/a> or leave a comment<\/a> for Kelly.\r\n   <\/p>
Another thing to note is the well-documented code. Kelly has included extensive help with an example. I'm also happy to see\r\n      the use of inputParser<\/tt><\/a>, validateattributes<\/tt><\/a>, and validatestring<\/tt><\/a> which are very powerful argument validation tools.\r\n   <\/p>\r\n