%f_gsafecmap.m
function gcmap = f_gsafecmap(nEl)
% This generates a colormap (gcmap) that renders well in grayscale.
% This is a refinement of Carey Rappaport's colormap CMRmap,
%
% http://www.mathworks.com/matlabcentral/fileexchange/2662-cmrmap-m
%
% C. Rappaport, “A color map for effective black-and-white rendering
% of color-scale images�, IEEE Antennas Propagat. Mag., vol. 44, no.
% 3, pp. 94–96, Jun. 2002.
%
%
% Optional Input: nEl - number of elements in colormap
 
if nargin<1
  nEl = 64;
end
 
CMRmap = [ ...
0.00,0.00,0.00; ...
0.15,0.15,0.50; ...
0.30,0.15,0.75; ...
0.60,0.20,0.50; ...
1.00,0.25,0.15; ...
0.90,0.50,0.00; ...
0.90,0.75,0.10; ...
0.90,0.90,0.50; ...
1.00,1.00,1.00];
 
x9 = linspace(0,1,9);
xcmap = linspace(0,1,nEl);
 
% resample to nEl values using splines
for i = 1:3
  gcmap(:,i) = interp1(x9,CMRmap(:,i),xcmap,'spline');
end
 
% maintain bounds
gcmap(gcmap<0)=0;
gcmap(gcmap>1)=1;
 
end