{"id":2513,"date":"2010-01-08T14:18:36","date_gmt":"2010-01-08T14:18:36","guid":{"rendered":"https:\/\/blogs.mathworks.com\/pick\/2010\/01\/08\/lutbar-a-colormap-tool-to-make-your-life-easier\/"},"modified":"2010-01-08T14:18:36","modified_gmt":"2010-01-08T14:18:36","slug":"lutbar-a-colormap-tool-to-make-your-life-easier","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/pick\/2010\/01\/08\/lutbar-a-colormap-tool-to-make-your-life-easier\/","title":{"rendered":"LUTBAR: A colormap tool to make your life easier"},"content":{"rendered":"
\r\n <\/introduction>\r\n

I don't know how many times I've spun my wheels, trying to determine the best colormap for a graphic I was working on, and\r\n cycling one-by-one through the built-in colormaps in MATLAB. MATLAB has many pre-defined colormaps<\/a>, and selecting the best one can be a tedious process. At least, it was<\/i> a tedious process. Us<\/a>'s LUTBAR<\/a> tool streamlines the process by creating a toolbar of available colormaps; clicking on any entry automatically updates the\r\n figure's colorbar and allows you to see your figure in a variety of different colors. Better yet, LUTBAR automatically includes\r\n built-in colormaps, and enables you to include custom colormaps as well.\r\n <\/p>\r\n

Let's say, for instance that you had this bit of code:<\/p>

figure('color'<\/span>,'w'<\/span>);\r\nL = 40 * membrane(1,25);\r\nx = -1:1\/25:1;\r\ns = surf(x,x',L,...<\/span>\r\n    'edgecolor'<\/span>,'none'<\/span>,...<\/span>\r\n    'FaceLighting'<\/span>,'phong'<\/span>, ...<\/span>\r\n    'AmbientStrength'<\/span>,0.3, ...<\/span>\r\n    'DiffuseStrength'<\/span>,0.6, ...<\/span>\r\n    'Clipping'<\/span>,'off'<\/span>,...<\/span>\r\n    'BackFaceLighting'<\/span>,'lit'<\/span>, ...<\/span>\r\n    'SpecularStrength'<\/span>,1.1, ...<\/span>\r\n    'SpecularColorReflectance'<\/span>,1, ...<\/span>\r\n    'SpecularExponent'<\/span>,7);\r\nset(gca,'visible'<\/span>,'off'<\/span>)\r\nlight('Position'<\/span>,[40 100 20], ...<\/span>\r\n    'Style'<\/span>,'local'<\/span>, ...<\/span>\r\n    'Color'<\/span>,[0 0.8 0.8]);\r\nlight('Position'<\/span>,[.5 -1 .4], ...<\/span>\r\n    'Color'<\/span>,[0.8 0.8 0]);<\/pre>
 <\/p>\r\n   
Most of you will probably recognize the L-shaped membrane; it plays an interesting and important role at The MathWorks.(For\r\n      the back story on our logo, check out Cleve's \"History of MATLAB\" video<\/a>; it's just over 8 minutes, and well worth a watch!)\r\n   <\/p>\r\n   
But you will also undoubtedly recognize that the coloring is \"wrong.\" I could cycle manually (or even automatically) through\r\n      the built-in colormaps:\r\n   <\/p>
mapOpts = {'autumn'<\/span>,'bone'<\/span>,'colorcube'<\/span>,'cool'<\/span>,...<\/span>\r\n           'copper'<\/span>,'flag'<\/span>,'gray'<\/span>,'hot'<\/span>,'hsv'<\/span>,...<\/span>\r\n           'jet'<\/span>,'lines'<\/span>,'pink'<\/span>,'prism'<\/span>,'spring'<\/span>,...<\/span>\r\n           'summer'<\/span>,'white'<\/span>,'winter'<\/span>};\r\nfor<\/span> ii = 1:numel(mapOpts)\r\n    set(gcf,'colormap'<\/span>,eval(mapOpts{ii}));\r\n    pause(0.5);\r\nend<\/span>\r\n\r\n<\/pre>\r\n
\r\n\r\n\r\n<\/embed>\r\n\r\n<\/p>\r\n\r\n   
Us gives us a cleaner, easier approach. All one has to do is issue the lutbar<\/tt> command:\r\n   <\/p>
lutbar<\/pre> 
<\/p>\r\n   
We now see a toolbar of selectable colormaps; clicking on any individual colormap icon updates the visualization. If you look with a careful eye,\r\n      you might notice a separation line on the toolbar to the right of the (blue-to-green) 'winter' map. That line delimits the\r\n      end of the built-in maps, and the beginning of a collection of user-defined maps. In fact, the last colormap on the toolbar\r\n      is really just a uniform red colormap of my creation. Applying it yields the MathWorks logo we all know and love.\r\n   <\/p>\r\n   
(Did you know that The MathWorks logo was uniformly colored, and that the apparent color gradations were created purely by\r\n      manipulating the lighting<\/a>?)\r\n   <\/p>\r\n   
Us's code is beautifully implemented and documented; we've come to expect nothing less from him. Thanks for sharing this great\r\n      function!\r\n   <\/p>\r\n   
Comments?<\/a><\/p>