Generate n different colors (for multiple classes plot)

Post date: May 9, 2012 2:10:34 AM

The trick here is to define color on the HSV space as it is more understandable. Here the saturation s and the shade v are fixed to 1, and the hue h is separated into n parts equally, each part with 360/n. Then the hsv is transformed back to rgb. the code can be found below:

function rgbList = generateColorList(n,option)

N = n+1;

h = linspace(0,1,N)'; % H components

s = ones(N,1); % S components

v = ones(N,1); % V component

hsv = [h s v];

hsv = hsv(1:end-1,:);

rgbList = hsv2rgb(hsv);

if nargin > 1

    if strcmp(lower(option.order),'shuffle')

        augmentedIndex = [1:n; n:-1:1];

        augmentedIndex = augmentedIndex(:);

        permutedIndex = augmentedIndex(1:n)';

        rgbList = rgbList(permutedIndex,:);

end

    if option.display == 1

        figure; scatter(1:n,1:n,30,rgbList,'s','filled');

end

end

To use it, run the command below:

colorList = generateColorList(NClass);