% function [rgb] = xyz2rgb(xyz)
%  
% // C-Code
% ref_X =  95.047        //Observer = 2°, Illuminant = D65
% ref_Y = 100.000
% ref_Z = 108.883
%
% var_X = X / 100        //X = From 0 to ref_X
% var_Y = Y / 100        //Y = From 0 to ref_Y
% var_Z = Z / 100        //Z = From 0 to ref_Y
%
% var_R = var_X *  3.2406 + var_Y * -1.5372 + var_Z * -0.4986
% var_G = var_X * -0.9689 + var_Y *  1.8758 + var_Z *  0.0415
% var_B = var_X *  0.0557 + var_Y * -0.2040 + var_Z *  1.0570
%
% if ( var_R > 0.0031308 ) var_R = 1.055 * ( var_R ^ ( 1 / 2.4 ) ) - 0.055
% else                     var_R = 12.92 * var_R
% if ( var_G > 0.0031308 ) var_G = 1.055 * ( var_G ^ ( 1 / 2.4 ) ) - 0.055
% else                     var_G = 12.92 * var_G
% if ( var_B > 0.0031308 ) var_B = 1.055 * ( var_B ^ ( 1 / 2.4 ) ) - 0.055
% else                     var_B = 12.92 * var_B
%
% Source http://www.easyrgb.com

function [rgb] = xyz2rgb(xyz)
[m,n] = size(xyz);

if ((m ~= 3) & (n == 3))
    xyz = xyz';
end;

% Observer = 2°, Illuminant = D65
t_mat = [[  3.240479 -1.537150 -0.498535 ]
         [ -0.969256  1.875992  0.041556 ]
         [  0.055648 -0.204043  1.057311 ]];

rgb_k = t_mat * xyz;
rgb = f1(rgb_k);

function rgb = f1(rgb_k)
thresh_n = 0.0031308;

[idx_m,idx_n] = find(rgb_k > thresh_n);
rgb(idx_m,idx_n) = 1.055*(rgb_k(idx_m,idx_n).^(1/2.4)) - 0.055;

[idx_m,idx_n] = find(rgb_k <= thresh_n);
rgb(idx_m,idx_n) = 12.92*rgb_k(idx_m,idx_n);