setColor_barByGroup(varargin)

function [varargout] = setColor_barByGroup(varargin)
% 
% SETCOLOR_BARBYGROUP change the color of a bar to same groups have the
%   same color.
% 
% SETCOLOR_BARBYGROUP(COLOR) change the color of a bar with N groups 
%   where the i-th group has the COLOR(i, :) color. 
%   COLOR is a  N-by-3 matrix color in RGB.
%   
%   COLOR can be a N-by-1 cell with string matlab colors: 'r','b','g',c', etc.
%   In this case function rgb.m is needed:
%   http://www.mathworks.com/matlabcentral/fileexchange/1805-rgb-m
% 
% 
% P = SETCOLOR_BARBYGROUP(...) return in the N-by-1 vector P the new patches 
%   associated to each group. 
% 
% 
% SETCOLOR_BARBYGROUP(AX, ...) AX is the axes to apply the color change.
% 
% 
% EXAMPLE: Change the current bar to red [1 0 0], blue [0 0 1] and green [0 1 0]
%   
%     bar(rand(3,5));
%     color = [1 0 0; 0 0 1; 0 1 0];
%     setColor_barByGroup(color);
% 
% 
% EXAMPLE: Change the subplot bar to the color {'r', 'b', 'g'} (needed
%     funciton: rgb.m)
% 
%     data = rand(3,5);
%     subplot(1,2,1);
%     bar(data);
%     subplot(1,2,2);
%     bar(data); 
%     p = setColor_barByGroup({'r', 'b', 'g'});
%  
% 
% tags: figure, bar, color, groups
% 
% 
% author: Mar Callau-Zori
% PhD student - Universidad Politecnica de Madrid
% 
% version: 1.0, December 2011.
% 

    [ax, color] = extractInputParameters(varargin{:});
    
    % apply: rgb.m
    if iscell(color)
        if exist('rgb.m','file')
            color = cell2mat(cellfun(@(x) rgb(x), color, 'UniformOutput', false)');
        else
            error('stat:setColor_barByGroup:notFoundRGB', 'Function rgb.m is needed');
        end
    end
        
    % get the axes patches
    h = findobj(ax,'type','patch');
    h = h(end:-1:1);
    set(h, 'Visible', 'on')
    
    numGroups = size(get(h(1), 'Xdata'), 2); 
    xData_cell = get(h, 'xData');
    yData_cell = get(h, 'yData');
    
    
    % plot patches
    p = NaN .* ones(1, numGroups);
    for iGroup=1:numGroups
        xData_iGroup = cell2mat(cellfun(@(x) x(:,iGroup),xData_cell ,'UniformOutput', false)');
        yData_iGroup = cell2mat(cellfun(@(x) x(:,iGroup),yData_cell,'UniformOutput', false)');
        p(iGroup) = patch(xData_iGroup, yData_iGroup, color(iGroup, :));
    end
    
    if nargout>0
        varargout{1} = p;
    end
            
end

function [ax, color] = extractInputParameters(varargin)

    if size(varargin{1},1) == 1 && size(varargin{1},1) == 2 && ...
            ishandle(varargin{1}) && strcmpi(get(varargin{1}, 'type'), 'axes')
        ax = varargin{1};
        varargin = varargin(2:end);
    else
        ax = gca;
    end
    
    if iscell(varargin{1}) || (isnumeric(varargin{1}) && length(varargin{1})==3)
        color = varargin{1};
        varargin = varargin(2:end);
    else
        error('stat:extractInputParameter:Required', 'The color_bar input parameter is required');
    end      
     
end