bichromatic(cols,varargin)

function map = bichromatic(cols,varargin)
%Bichromatic colormap: bichromatic(cols,varargin)
%
% Examples:
%   map = bichromatic; 
%   map = bichromatic(cols); 
%   map = bichromatic([],len); 
%   B = bichromatic(cols, A);
%   B = bichromatic(cols, A, lims);
%
% Similar to other colormap functions that interpolate between 2 fixed colors
% except the colors are variable. 
%
% The function can additionally be used to convert a real-valued array into
% a truecolor array using the colormap.
%
% IN:
%   len - Scalar length of the output colormap. If len == Inf the concise
%         table is returned. Default: len = size(get(gcf, 'Colormap'), 1);
%   A - Non-scalar numeric array of real values to be converted into
%       truecolor.
%   lims - 1x2 array of saturation limits to be used on A. Default:
%          [min(A(:)) max(A(:))].
%   cols - a 2X3 matrix with 2 RGB vectors. Note cols(1,:) is the low
%          color, cols(2,:) is the high valued color. If cols = [], defaults
%          to grayscale
%
% OUT:
%   map - (len)xJ colormap table. J = 3, except in the concise case, when
%         J = 4, map(1:end-1,4) giving the relative sizes of the 
%         inter-color bins.
%   B - size(A)x3 truecolor array.

% Based on Oliver Woodford's colormap/real2rgb submission in the MATLAB FEX

if isempty(cols) || (nargin == 0)
    cols = [0 0 0;1 1 1];
end

map = [cols(1,:); cols(2,:)];
map = colormap_helper(map, varargin{:});