AdjustColorMap

AdjustColorMap - Adjust colormap for current figure, i.e. change gamma.

  USAGE

    m = AdjustColorMap(<options>)

    <options>      optional list of property-value pairs (see table below)

    =========================================================================
     Properties    Values
    -------------------------------------------------------------------------
     'shift'       proportional hue shift (0 = no change, default)
     'gamma'       standard gamma for luminance (1 = no change, default)
     'hgamma'      gamma for hue (1 = no change, default)
     'hrotate'     proportional hue rotation (0 = no change, default)
    =========================================================================

0001 function m = AdjustColorMap(varargin)
0002 
0003 %AdjustColorMap - Adjust colormap for current figure, i.e. change gamma.
0004 %
0005 %  USAGE
0006 %
0007 %    m = AdjustColorMap(<options>)
0008 %
0009 %    <options>      optional list of property-value pairs (see table below)
0010 %
0011 %    =========================================================================
0012 %     Properties    Values
0013 %    -------------------------------------------------------------------------
0014 %     'shift'       proportional hue shift (0 = no change, default)
0015 %     'gamma'       standard gamma for luminance (1 = no change, default)
0016 %     'hgamma'      gamma for hue (1 = no change, default)
0017 %     'hrotate'     proportional hue rotation (0 = no change, default)
0018 %    =========================================================================
0019 
0020 % Copyright (C) 2013 by Michaël Zugaro
0021 %
0022 % This program is free software; you can redistribute it and/or modify
0023 % it under the terms of the GNU General Public License as published by
0024 % the Free Software Foundation; either version 3 of the License, or
0025 % (at your option) any later version.
0026 
0027 % Default values
0028 gamma = 1;
0029 hgamma = 1;
0030 hrotate = 1;
0031 shift = 0;
0032 
0033 % Parse parameter list
0034 for i = 1:2:length(varargin),
0035     if ~ischar(varargin{i}),
0036         error(['Parameter ' num2str(i+2) ' is not a property (type ''help <a href="matlab:help AdjustColorMap">AdjustColorMap</a>'' for details).']);
0037     end
0038     switch(lower(varargin{i})),
0039         case 'gamma',
0040             gamma = varargin{i+1};
0041             if ~isdscalar(gamma,'>=0'),
0042             error('Incorrect value for property ''gamma'' (type ''help <a href="matlab:help AdjustColorMap">AdjustColorMap</a>'' for details).');
0043             end
0044         case 'hgamma',
0045             hgamma = varargin{i+1};
0046             if ~isdscalar(hgamma,'>=0'),
0047             error('Incorrect value for property ''hgamma'' (type ''help <a href="matlab:help AdjustColorMap">AdjustColorMap</a>'' for details).');
0048             end
0049         case 'shift',
0050             shift = varargin{i+1};
0051             if ~isdscalar(shift),
0052             error('Incorrect value for property ''shift'' (type ''help <a href="matlab:help AdjustColorMap">AdjustColorMap</a>'' for details).');
0053             end
0054         case 'hrotate',
0055             hrotate = varargin{i+1};
0056             if ~isdscalar(hrotate),
0057             error('Incorrect value for property ''hrotate'' (type ''help <a href="matlab:help AdjustColorMap">AdjustColorMap</a>'' for details).');
0058             end
0059         otherwise,
0060             error(['Unknown property ''' num2str(varargin{i}) ''' (type ''help <a href="matlab:help AdjustColorMap">AdjustColorMap</a>'' for details).']);
0061     end
0062 end
0063 
0064 % Convert from RGB to HSL
0065 hsl = hsv2hsl(rgb2hsv(colormap));
0066 h = hsl(:,1);
0067 s = hsl(:,2);
0068 l = hsl(:,3);
0069 
0070 % Correct luminance and hue gammas
0071 h = h .^ (1/hgamma);
0072 l = l .^ (1/gamma);
0073 
0074 % Convert from HSL to RGB
0075 m = hsv2rgb(hsl2hsv([h s l]));
0076 %  bad = any(isnan(m),2);
0077 %  m(bad,:) = [];
0078 %  m = Clip(m,0,1);
0079 
0080 % Rotate colors
0081 n = size(m,1);
0082 r = mod(round(abs(hrotate)*n),n);
0083 m = [m(r+1:end,:) ; m(1:r,:)];
0084 
0085 % Correct hue
0086 l = size(m,1);
0087 n = round(abs(shift)*l);
0088 if shift > 0,
0089     m = [m ; repmat(m(end,:),n,1)];
0090 elseif shift < 0,
0091     m = [repmat(m(1,:),n,1) ; m];
0092 end
0093 
0094 % Apply
0095 colormap(m);
0096 
0097 
0098 
0099 
0100 
0101 
0102 
0103 
0104 %  % Convert RGB to HSV
0105 %  hsv = rgb2hsv(colormap);
0106 %
0107 %  % Convert HSV to HSL
0108 %  h = hsv(:,1);
0109 %  s = hsv(:,2) .* hsv(:,3);
0110 %  l = (2-hsv(:,2)).*hsv(:,3);
0111 %  if l <= 1,
0112 %      s = s ./ l;
0113 %  else
0114 %      s = s ./ (2-l);
0115 %  end
0116 %  l = l/2;
0117 %
0118 %  % Correct gamma
0119 %  l = l .^ (1/gamma);
0120 %
0121 %  % Convert HSL to HSV
0122 %  hsv(:,1) = h .^ (1/hgamma);
0123 %  l = l * 2;
0124 %  if l <= 1,
0125 %      s = s .* l;
0126 %  else
0127 %      s = s .* (2-l);
0128 %  end
0129 %  hsv(:,2) = (2 * s) ./ (l + s);
0130 %  hsv(:,3) = (l + s) / 2;
0131 %
0132 %  % Convert to RGB
0133 %  m = hsv2rgb(hsv);
0134 %  bad = any(isnan(m),2);
0135 %  m(bad,:) = [];
0136 %  m = Clip(m,0,1);
0137 %
0138 %  % Rotate colors
0139 %  n = size(m,1);
0140 %  r = mod(round(abs(hrotate)*n),n);
0141 %  m = [m(r+1:end,:) ; m(1:r,:)];
0142 %
0143 %  % Correct hue
0144 %  l = size(m,1);
0145 %  n = round(abs(shift)*l);
0146 %  if shift > 0,
0147 %      m = [m ; repmat(m(end,:),n,1)];
0148 %  elseif shift < 0,
0149 %      m = [repmat(m(1,:),n,1) ; m];
0150 %  end
0151 %
0152 %  % Apply
0153 %  colormap(m);