Monochrome

Monochrome - Monochrome colormap (from white to a given color).

  USAGE

    m = Monochrome(color,n,<options>)

    color          optional target color (default = black)
    n              optional number of rows in output matrix (default = 100)
    <options>      optional list of property-value pairs (see table below)

    =========================================================================
     Properties    Values
    -------------------------------------------------------------------------
     'hgamma'      gamma-like correction for hue (1 = no correction, default)
    =========================================================================

0001 function m = Monochrome(color,n,varargin)
0002 
0003 %Monochrome - Monochrome colormap (from white to a given color).
0004 %
0005 %  USAGE
0006 %
0007 %    m = Monochrome(color,n,<options>)
0008 %
0009 %    color          optional target color (default = black)
0010 %    n              optional number of rows in output matrix (default = 100)
0011 %    <options>      optional list of property-value pairs (see table below)
0012 %
0013 %    =========================================================================
0014 %     Properties    Values
0015 %    -------------------------------------------------------------------------
0016 %     'hgamma'      gamma-like correction for hue (1 = no correction, default)
0017 %    =========================================================================
0018 
0019 % Copyright (C) 2009-2018 by Michaël Zugaro
0020 %
0021 % This program is free software; you can redistribute it and/or modify
0022 % it under the terms of the GNU General Public License as published by
0023 % the Free Software Foundation; either version 3 of the License, or
0024 % (at your option) any later version.
0025 
0026 % Default values
0027 hgamma = 1;
0028 type = 'linear';
0029 n0 = 100;
0030 color0 = [0 0 0];
0031 
0032 % Optional parameters
0033 if nargin == 0,
0034     % No parameter, use default color and n rows
0035     color = color0;
0036     n = n0;
0037 elseif nargin == 1,
0038     if isdvector(color,'#3','>=0'),
0039         % One parameter = color, use default n rows
0040         n = n0;
0041     elseif isiscalar(color),
0042         % One parameter = n rows, use default color
0043         n = color;
0044         color = color0;
0045     else
0046         % One parameter = neither color nor n rows, error
0047         error('Incorrect parameter (type ''help <a href="matlab:help Monochrome">Monochrome</a>'' for details).');
0048     end
0049 else
0050     if isdvector(color,'#3','>=0'),
0051         % First parameter is color
0052         if ischar(n),
0053             % Second is an option, use default n rows
0054             varargin = {n,varargin{:}};
0055             n = n0;
0056         elseif ~isiscalar(n),
0057             % Second is neither n rows nor an option, error
0058             error('Incorrect number of output rows (type ''help <a href="matlab:help Monochrome">Monochrome</a>'' for details).');
0059         end
0060     elseif isiscalar(color),
0061         % First parameter is n rows, use default color
0062         varargin = {n,varargin{:}};
0063         n = color;
0064         color = color0;
0065     else
0066         % First parameter is an option, use default color and n rows
0067         varargin = {color,n,varargin{:}};
0068         n = n0;
0069         color = color0;
0070     end
0071 end
0072 
0073 % Check number of parameters
0074 if mod(length(varargin),2) ~= 0,
0075   error('Incorrect number of parameters (type ''help <a href="matlab:help Monochrome">Monochrome</a>'' for details).');
0076 end
0077 
0078 
0079 % Parse parameter list
0080 for i = 1:2:length(varargin),
0081     if ~ischar(varargin{i}),
0082         error(['Parameter ' num2str(i+2) ' is not a property (type ''help <a href="matlab:help Monochrome">Monochrome</a>'' for details).']);
0083     end
0084     switch(lower(varargin{i})),
0085         case 'hgamma',
0086             hgamma = varargin{i+1};
0087             if ~isdscalar(hgamma,'>=0'),
0088             error('Incorrect value for property ''hgamma'' (type ''help <a href="matlab:help Monochrome">Monochrome</a>'' for details).');
0089             end
0090         otherwise,
0091             error(['Unknown property ''' num2str(varargin{i}) ''' (type ''help <a href="matlab:help Monochrome">Monochrome</a>'' for details).']);
0092     end
0093 end
0094 
0095 for i = 1:3,
0096     m(:,i) = linspace(1,color(i),n).^(1/hgamma);
0097 end