{"id":2631,"date":"2010-12-23T19:54:50","date_gmt":"2010-12-23T19:54:50","guid":{"rendered":"https:\/\/blogs.mathworks.com\/pick\/2010\/12\/23\/generate-distinct-colors-for-your-matlab-plots\/"},"modified":"2010-12-23T19:54:50","modified_gmt":"2010-12-23T19:54:50","slug":"generate-distinct-colors-for-your-matlab-plots","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/pick\/2010\/12\/23\/generate-distinct-colors-for-your-matlab-plots\/","title":{"rendered":"Generate Distinct Colors for Your MATLAB Plots"},"content":{"rendered":"
\r\n <\/introduction>\r\n

Brett<\/a>'s Pick this week is \"Generate Maximally Perceptually-Distinct Colors,\"<\/a>, by Tim Holy<\/a>.\r\n <\/p>\r\n

Today, I'm going out on a limb: I'm going to Pick a new file from a new File Exchange author. As of this writing, \"Generate\r\n Maximally-Perceptually Distinct Colors\" (GMPDC)--the author's first File Exchange submission (welcome!)--has been downloaded\r\n only three times. (My download was the third.) However, I was excited to see this file, and I know it will come in handy.\r\n In fact, I've often considered writing something like this myself--but have never gotten around to it.\r\n <\/p>\r\n

So what does GMPDC do? It provides an easy way to generate distinct, differentiable colors in which to plot a long sequence\r\n of objects (like lines).\r\n <\/p>\r\n

MATLAB ships with several built-in colormaps that are useful in different situations. One of those, \"lines,\" is a repeating\r\n array of seven distinct colors. By default, MATLAB axes cycle through these seven different colors when plotting lines:\r\n <\/p>\r\n

<\/p>

%<\/span>\r\n% You can see the default color order with:<\/span>\r\n\r\nget(0,'DefaultAxesColorOrder'<\/span>)\r\n\r\n% and you can verify that they are the same as the repeating sequence in<\/span>\r\n% \"lines\" with<\/span>\r\n\r\nisequal(lines(7),get(0,'DefaultAxesColorOrder'<\/span>))<\/pre>
ans =\r\n         0         0    1.0000\r\n    1.0000         0         0\r\n         0    1.0000         0\r\n         0         0    0.1724\r\n    1.0000    0.1034    0.7241\r\n    1.0000    0.8276         0\r\n         0    0.3448         0\r\nans =\r\n     1\r\n<\/pre>
Sometimes, however, I want to be able to differentiate more than 7 lines or plots. In the past, I've monkeyed about with custom\r\n      color orders I made up on the fly. Tim makes it easy to standardize those colors; the colors returned by GMPDC are consistent\r\n      regardless of the number of colors you request. As a bonus, one can specify a background color as an optional input to ensure\r\n      that your colors differ from the background, as well as from each other:\r\n   <\/p>\r\n   
 <\/p>\r\n   
Tim worked in the L*a*b* colorspace, which was designed to approximate human color perception. His code is solid and well\r\n      implemented, with nice documentation. I hope this file is a harbinger of more good stuff to come from this author.\r\n   <\/p>\r\n   
Note that the default \"colororder\" property can be readily modified. In fact, I just added a line to my startup file<\/a> to set my colororder to be distinguishable_colors(20)<\/tt>. Thanks, Tim!\r\n   <\/p>\r\n   
Try GMPDC for yourself; you'll be modifying your own startup files before you know it! let us know what you think<\/a>, or leave a comment for Tim here<\/a>.\r\n   <\/p>